Civic ed3 d15b4 dual carbs

[bobval]

Hi all
dual carbs are often contaminated with fuel deposits, mostly caused by evaporates that clog carby jets, airways and internal surfaces. This is particularly so with vehicles left standing in hot sun. Never buy a used old honda from a car yard without demanding the Caltex Techron 5000 treatment prior to payment. Techron 5000 will dissolve all fuel contaminates over a period of about two weeks. Patience is required to force sufficient Techron 5000 true the entire fuel system, about 500 KMS. Do not contemplate interfering with carbs physically until the Techron 5000 solution has been given time to work wonders. Once a year thereafter give the tank a 350 ml dose of Techron 5000 to a 40 ltr tank, use Caltex 98 RON for this dosed tank. I restored a Civic 1991 ed3 that was totally contaminated and inoperable in a fortnight. The dealer dumped the car with 148000 kms, immaculate one only old lady driver in 23 years for $650 as a carby overhaul was quoted at plus $1700, carbies out sent to Sydney cleaned returned and reinstalled. Techron 5000 cost me $15, car is perfect.

[bboyzell]

Hi Bob

A very interesting first post, almost feels like a ad for Techron 5000 lol

Got any pictures of your ED3?

[dove grey 64]

Does sound like an advertisement. Why would you demand the car yard to do it? Wouldn't you be better off buying the car in what they think is ruined for a cheaper price.
Also I dont use caltex fuel, all of my cars get less k's from a tank full compared to shell and bp.
How do you initially use your product?
I took out the floats, cleaned with steel wool and afm cleaner, reassembled and worked perfectly. Wouldnt mind some sort of fuel system cleaner additive though.

[bobval]

A bit to add
Thanks for the quick responses. The Caltex Techron 5000 blurb actually came from a USA Honda site even though the reference had been posted by an Australian engineer. The USA name is different though, Caltex is only used for Australia. The original Whirlpool USA post was two pages long and highly informative, I still have a copy. All in all much is the same, my version is highly condensed. The Australian engineer remarks that he has used many other brands and compounds to de carb and remove fuel precipitates from mostly quite old veteran cars or so it seems anything from Ferrari to Rolls Royce. I guess he is a professional car restorer. His claim is that nothing is as successful as Techron 5000. The advice is to double the concentrate on initial application, 375 ml to 20 ltrs or 750 mls to a full 40 ltr tank. For some reason 98 RON is recommended., hence Caltex or BP in Australia. He was quite correct in stating that a smoking trail of black exhaust will occur, spitting out clumps of carbon solids for a couple of days. Boy! the engine sure cleans itself. Suffer for a fortnight and as the carby cleans, carbon deposits on valves, combustion chamber, piston heads etc burn off and are exhausted, the engine will seem like a new model. My compression went up from 165 psi (all 4) to just over 170+ (all 4). The Civic ed3 has probably never exceeded 4000 rpm in the entire 23 years. gearbox is slick, acceleration and fuel economy spot on for the model (around 11 ltsX100 kms suburban). No body damage, a few scratches, unmarked seats, pedals dash and interior. Always garaged, never used at night, if it rains, too hot, carried passengers or beyond the local shops or church on Sunday. I have changed the trailing arm bushes with Nolex, all OEM rubber are 100%. Steering was downright dangerous until Jax Quickfit tyres told me the tyres with about 70,000 km on them and at 65% wear were in fact 15 years old, a hard compound rubber and acted as ice skates as well as the alignment and balance was well out of true. Understeer was frightening. Fantastic return to a perfectly balanced car after new front tyres, 185X14 and alignment plus of course the handling improvement with trailing arm bushes. LOL never noticed, never exceeded 60kmph, always changed up or down by 3000rpm. I am unlikely to exceed 180,000 kms in it and as it is only used by me, same as LOL, for suburban shopping all in a 60kmph zone with two 40kmph school zones on the way to Woolworths with speed humps and roundabouts I have to act the hoon to exceed 3250 rpm. By the way I will be 75 next month. I never drive in peak hour, at night, if it rains or is too hot or carry passengers the Civic does not realise it has a 2nd owner. I live in the ACT and the car was sold in May 1991 in Batemans Bay, never used in dust, rust free or seems to have gone anywhere, Average usage is about 7200 kms per year for the 23 years, all in a seaside country town, no city traffic thank you. The a/c runs at OEM specs, brakes are 100%, I did fit new rear shoes and cylinders and machined drums. Clutch is as new, no thrust bearing weakness, all syncro's click into place. The car must have been a deceased estate, no papers being provided, no service records but it is obvious that all service plus timing belt had been done in 2007 at around 130,000kms. Only 16000kms since then. OEM timing belt sticker attached but the dealers halfwit car cleaner steam cleaned off a/c sticker and service record. I can tell the mechanic did not fit a new rocker cover gasket at valve and belt exchange, a slight oil leak from cover seal. My highly regarded mechanic has passed the Civic as faultless, but one has to pay him accordingly, still a good job is worth 10 time a cheap poor disinterested mechanic. Honda virtually put the dogs on me when I had the effrontery to seek their assistance. Honda cars over 5 years old are not welcome in Canberra Honda dealerships, everyone who buys a Honda here is filthy rich.

[bobval]

Guess the Techron 5000 blurb sounds an advert from Caltex. here is the original whirlpool post
forums.whirlpool.net.au/archives/933463
schroll down about twenty posts to wilbyz user 3548
Roger Costello posts that Techron 5000 (not the 1000 product) was developed in the USA by Chevron (Caltex parent company) to comply with Californian legislation that demands fuel additives be contained in all fuel. The principle reason is removal and prevention of carbon build up however at the same time Techron 5000 also prevents fuel contamination by soluble items commonly refered to as "gunk". My car had been left standing on the car lot throughout a Canberra summer in temperatures well over 40-50 deg C. Unused, never started with at best 5 lts of fuel in the tank that caused fuel evaporation to coat all internal fuel surfaces, tank, pump, pressure control valve, carburetor internals with a shellac that once re immersed in fresh fuel broke down into a first stage glutinous long stranded substance that cloged all fuel flow passageways. Fortunately the Civic D15B4 twin carb only has a choke blade on one carby, the left side one. That is the principle cause of carby malfunction, it is the idle and slow jets here that prevent cylinders 1 and 2 from firing. 3/4 are less affected and will manage a partial fuel flow. From a two cylinder engine, with the patience of Job, one must daily run the engine to commence dissolving the glutinous glug from all jets, passages, air and fuel, bowl etc from both carbies. Takes time but each run gets more Techron 5000 into where it is needed. Overnight solubility occurs also. Three days in the underground car park was needed to even get it outside. From then on each running improved performance but it was nearly a week of 15 minute runs, at first 1850 rpm, until I could get 3000 rpm out of the engine. Three months later I could rev up to 5500 if I had wanted. As I posted earlier $15 total cost, plus the 98 ron fuel not $1700 for a carby removal, strip, clean, rebuild and install plus the tow truck. I really cannot detect much difference from running a 9.2:1 compression engine with either 91 RON or 98 RON fuel.
Chevron USA or in Australia, Caltex, Techron 5000, a product invented, manufactured and sold exclusively by Caltex is unbeatable, maybe the others work, I do not know nor care.

[dove grey 64]

Odd you recorded an increase in compression after de carbonisation, carbon sitting on pistons will actually give you higher compression reading. Its an old mini racing trick to use pistons with the largest carbon build up you can source to increase compression in a regulated race class by motor capacity
Either way good stuff.

[bobval]

decarb compressions
A build up of carbon around the valve seats both on the valve and in the head will cause incorrect seating of the valves, mostly exhaust valves. A tighter valve seat will allow a little higher compression than a poor sealing valve seat. Also pre ignition from carbon coating piston crowns upsets the valve timing, none of this assists correct engine operation. Most engine carbon removal products feature cleaning valve seats as the essential action of the product. Carbon deposits in the engine rarely increase compression without adverse effects, mostly causing pinging or pre ignition. Not good, called engine destruction. My compression, to tell the truth, probably only increased by a few lbs per sq inch, the gauge cannot be read with that degree of accuracy. Lets call it 168 lbs per sq inch from a recorded 165 lbs per square inch.

[dove grey 64]

True, in a series mini motors you use carboned pistons with fresh heads to gain compression the sneaky way in a regulated race class.
Ssscchhhhhh

[bobval]

Dove Grey 64
Seem a convulted way to increase compression ratio. If the head has to come of so as to lap the valve seats with a grinding paste, how does the carbon layer manage to stay evenly over the piston crowns? We did this in the 1950's anyway as a usual procedure, except most of us painstakingly scratched the carbon off the pistons and rebuffed them. Cars in those days ran compressions around the 7:1 - 8.8:1 mark all on 80 octane leaded fuel. 80 octane was the premium grade, standard crap fuel was more like 76 octane with water and dirt thrown in for free. Engines were not interference head valve designs, so no piston/valve strike problems. To increase compression a head shave and head gasket change was preferred, lousy con rods generally failed along with shim bearings unable to take the strain.
Bobval

[dove grey 64]

Yeah its an odd way to gain an advantage but your forced to find loopholes when racing in such a tightly regulated class.
We're getting off topic and showing our age a bit too :)
Good results with your motor. If there was anything wrong with my D15b4 id of been more inclined to bin it as it seems there hundreds at wreckers which is a shame, mine has clicked over 480, 000 ks and has never been opened.
Good tough little engine

[mkrs_adelaide]

I've been trolling the civic twin carb forums for a whole week looking for that aha post which solves my carby problem, but so far, no bullseye. The techron 5000 post series really caught my eye and thanks for that info. I remain confident that I can solve the stalling problem without resorting to pulling the carbs off the car.

Some history....Me. a 55yo engineer ex aerospace, electronics ticket and a hoon from way back. First person in oz to design and campaign a nitrous and liquid phase LPG injection system on a 240 zed in 1984. Fast forward to 1996 where I bring home a brand new daughter in our 2 door 92 vintage civic gl. Still have the civic, from new, and that daughter, now full of pierced ears and attitude, is the new owner of that civic. And it stalls. All the time.

You might have guessed I will be fixing this thing myself. So far, I have grabbed a spare set of carbs from the Lonsdale wreckers, today actually, and pulled them to pieces on the dining table. Impressive. Compared to the hitachis on the 240z which I still have, these Keihins have a lot of paths for air and fuel to go. Being an idle problem, I am chasing the likely cause of blockage in the idle circuit. Three circuits are evident. The main jet which is part of the slide piston, a transition circuit which pops out just downstream from the main jet, and finally, the idle circuit which seems to go via a solenoid o the side of each carby. The idle jets exit right at the base of the throttle plate, via a gaggle of tiny holes.

I am convinced those idle holes see no fuel.

The car goes. Mind, it sat asleep for a few years and no doubt got the fuel varnish blues. But to drive it, you have to thrash it. Anything under 1000rpm and she dies. Revs hard to 7000rpm.

OK, what do you guys recommend. Those solenoids look like anti diesel solenoids, and may reveal something if I remove for inspection. Better than a full strip.

By the way, first evidence of this idle problem was one minute after starting with little fuel, after a one year sleep. Looks like clogged jets eh?

Any advice on those solenoids, like are they continuously energised during operation, and the idle circuits in general, would be appreciated. Thanks and hi to all. My daughter has my hoon dna, which is a concern....Keeps pestering me about that old nitrous bottle.

[bobval]

Your symptoms are exactly as mine were prior to Techron 5000 treatment. Follow the dosage requirements and be prepared to allow the formula to take time to clean out the deposits. Weeks or hundreds of kilometers are needed. To prevent the problem re occurring either switch over to Caltex 95 RON or as I will do, just give the 40 lt tank a belly full of $15 Techron 5000 every year. For me a year is only about 5000 ks. 91 RON makes no difference to performance or fuel consumption with a 9.2:1 compression engine never exceeding 3250 RPM.

[mkrs_adelaide]

Thanks Bobval for that. Since my last post, I have put fuel treatment in the tank, and some in the carbies. And turned the idle set screw up to make it idle at 1500rpm. Now it can at least be driven without having to heel and toe or left foot brake everywhere. I will take the car for a few runs to Clare in a few weeks. I also pulled one of the anti diesel solenoids off and chopped its little head off. (Didn't make any difference) Still wants to stall but it seems a little better than a week ago.

I have a photocopy of the factory diagnostic flowcharts for these carbs. Got them when I bought the car in 1992. So many things can make for poor idle besides dirty carbs. I will hold off digging into the PGM-carb electricals till I can say I gave the fuel treatment a good 500km.

Wish me luck.

[bobval]

MKR Adelaide
Good luck with the Techron 5000 treatment. A run up to Claire should get the Techron where it can dissolve precipitates. Of course there are numerous problems that can also affect the carbies. Air leaks in the vacuum lines is a number one issue, also the dubious wax operated choke control is another along with a little regarded fuel pressure control valve situated in the intake fuel line between the crank operated fuel pump and the carby inlet. Once carburetors have been disassembled outside of a very professional rebuild and refit specialist who without exception discards absolutely all previous gaskets, O rings, jets and anything else supplied in a rebuild kit and who re tightens all bolts to torque specs, then I would be inclined to start all over again, assuming previous sloppy workmanship. I carried out a sloppy rebuild and refit on an older 1980 Accord some years ago. Similar symptoms but a painstaking total rebuild of the carby solved the idle and low speed stall. It turned out to be a warped manifold carby flange out of specs for the gasket. Made a new gasket from thicker gasket material, squirted sealant all over and around joint. Worked!.

[mkrs_adelaide]

Thanks again Bobval. All good points. The carbies have never been previously serviced by me or Honda and everything remains undisturbed from 1992. Part of my reluctance to pull it all apart, coz I'm sure there will be collateral damage to hoses. Choke mechanism looks OK, Adelaide's hot weather means the choke butterflies are half open at first start. My carbs have one choke mechanism on each carb. The accelerator pump mechanism is nifty. One pump only, feeding both carbies. Fuel regulator would be fine as I get good power at high revs wide open throttle.

Fully agree that some vacuum leak may have sprung up. Here's something I forgot to mention last post. Now that I've turned the idle up to 1500rpm, it basically idles OK, BUT....after a minute or two at speed, when I pull up at the lights, its a lottery as to if it stalls or goes back to 1500 rpm. Like, its one or the other. That is not something you see with a traditional air leak. More like some errant carb control solenoid. Poor daughter watching me left foot braking while I madly blip the throttle as I pull up to the lights. Puts her off ever driving the car.

Daughter's mum's new partner knows a mechanic. Apparently if I don't nail the problem before my sabbatical to Clare for vintage 2014, (late Feb) this mechanic will 'fix the problem'. Gulp. I'd rather let daughter have my old hush puppy Maxima and I persevere with the honda, seeing I'll be the one dealing with any issues down track.

Enough rambling. I'm also hoping to bump into an old high school mate who worked for honda as a mechanic and worked on the car in the early 90's. Garry Keen, if you are out there...........

Thanks Bobval. Cheers to all. MKRS

[Vvvtec]

I feel like ive just opened a time capsual

[bobval]

MKRS Adelaide
Have you changed the Ryco Z616 fuel filter located in the rear offside wheel arch? Low pressure fuel supply can effect idle. The choke thermowax valve cannot be dismantled nor checked for operation other than by vacuum testing or noting the opener rod movement. Hot water at correct engine temperature melts the wax pellet, a sticky choke blade in the carby throat will cause over rich mixture thus ensuing engine stalling. Vacuum lines are a problem. Apart from blockages in the carby fuel and air jets and passageways from precipitates, hopefully not grit or sediment, an entirely different matter, over rich mixture causes most of your problems as well. Keep us posted on outcomes, especially the well needed trip to Clare for driver repair. Bobval

[bobval]

MKRS
Just been viewing stacks of old posts on Keihin 2 barrel DA76B carbs, mostly USA crap dated up to 1997. The USA ceased the Keihin carbs after 1987. The problem we both suffered was so common that most people scrapped the Keihins for Webbers due to complexity and cost of repair. It seems 90% of the cause was located within the CV valve, certainly the wax pellet choke control, vacuum leaks and of course contaminated fuel jets and airways. Even in the USA in the early 90's carburetor overhaul was being quoted around $500, but a firm in Florida would overhaul your carby for around $350. Only USA customers. Civics and Accords that used Keihin were being dumped as unreliable and became student giveaways. One must presume that the Techron 5000 solution did not exist and people were focused on physical disassembly without being aware of the actual cause or causes of carby failure. The Keihin is a nightmare to service or understand the principle of operation, CVCC altered all we understood about standard carburetors. Fix it by Techron 5000, a full vacuum check, fuel filter change, correct operation of the choke opener, a fuel mixture adjustment ( only possible by a qualified workshop) and if all fails, dump it as no longer economic to repair. Bobval

[bobval]

MKRS
You had me concerned over the reference to anti diesel and then reference to carburetor solenoid until I realized you actually are referring to the idle cutoff solenoid. These solenoids only have one purpose and that is to shut off fuel supply to the idle jet once the ignition circuit is closed. Dieseling is an old term meaning engine run on after ignition is switched off in a petrol engine. An idle solenoid in the off position due to electrical fault will prevent fuel from entering the idle jet. the same solenoid left open due to a fault will cause what you refer to as dieseling. Get a new one and reconnect to the ignition circuit. The Keihin carburetor needs every bit of hardware designed as OEM. Read up on the Keihin carby and particularly in regard to Honda CVCC D15B4 and you will note a total dependence on air pressure within the carby, both positive and negative. The dam thing works on air pressure as well as fuel flow, both in very restricted volumes, somewhere around 16:1 (16 times air volume to 1 times fuel) over the 16:1 is running too lean and under is too rich. At 12:1 it is probably flooding. There in lies your major problem, the jets are clogged, especially the idle and low speed jets. The Keihin is a dual barrel carburetor, one barrel is dedicated to full fuel flow or what is termed high speed jet, and the other barrel is dedicated to idle and low speed fuel flow. How the fuel flow is switched is beyond my knowledge but this explains why you believe that the carby works at high speed, the larger jet is clear. Also high speed fuel flow also increases pressure of both fuel and air thus over riding minor or incipient clogging in the high speed jet. The other barrel, the low speed is not so lucky, that is the clogged circuit. Either Techron 5000 or a strip and rejet plus clean. A removal strip and rebuild of the Keihin carby outside of a specialist workshop and I doubt if there are more than two in Australia, charging at least $1500 for the job, will result in failure. People claim all sorts of success but mathematically they cannot prove a thing other than it sounds right. RPM counters, dyno testing, CO2 monitoring, EGA machine only available in a workshop can set up a carby, and then the mechanic has to be highly skilled. All the carburetor men are dead, retired or suffering dementia by now.
Bobval, Good luck

[mkrs_adelaide]

Hi Bobval,
I can almost hear the civic laughing at me when I walk past it in the morning! The car wants to stall all the time now, so either its getting worse or the idle screw I adjusted is slowly retracting. Will check that screw. The car does run on a wee bit now that I've chopped the head off one of the anti diesel solenoids. Thats a GOOD sign coz it means fuel is actually making it to that carbie's idle jets. I will chop the other solenoid's head off today and see what happens.
Regarding the anti diesel solenoids, I understand they serve a dual purpose on these carbs. Typical Honda, to improve fuel economy, those solenoids also cut off fuel to the idle jets when the engine is on over-run above 1500rpm. It used to annoy me endlessly back when, coz I could feel the fuel cut out and back in and it made for a jerky power delivery at light throttle. Damn you honda!
Anyway, Bobval, your warnings about getting the carbs refurbished by anyone other than a specialist have been heeded. Time to bury my head in those flowcharts and find the ECU so I can start counting flashing lights. Would be silly of me if the car was trying to tell me which component was broken.
Cheers Bobval, and again, if theres anyone out there who is a gun on these carbies, don't just sit there laughing at me. I will fix this damn car......
MKRS

[mkrs_adelaide]

Hi again Bobval, just dawned on me that Keihin have two types of carby on the AUDM civics of the late 80s/early 90s. The smaller engined breeze had a dual barrel single carb, the GL had the twin carbs. The US website info you gave is for the dual barrel single carb, which incidentally has only one choke plate like you mentioned in an early post.

I don't know the part number of the twin carbs but sadly, the twin carbs are a whole lot more complicated, especially in the idle control. My workshop manual extracts cover both carb types.

Weather's nice today.....Time to attack to civic......

MKRS

[bobval]

MKRS
I committed the fatal and unforgivable crime of assuming that the only reference I could locate for the Keihin dual carb was merely two of the single double barrel carbs constructed together. Crap! completely different carbs and never released in the USA, at least not the version we have for the Australian only marketed, ED3 D15B4 Civic GL. In fact our GL differs from all other markets. Seems we got a 9.2:1 compression and the English version was a 9.7:1, it was a D15B variation. The ED3 (ED is European right hand drive designation, Japan had the JDM version also running higher compressions.) was manufactured from late 1987 until final batch for OZ in late 1991. It is referred to as the Civic 1987-1991. Mine is a Japanese manufactured October 1990 model, OZ compliance plated January 1991, sold May 1991. It appears that no workshop manual has ever been released for the Australian version, Honda must have had confidential copies to monopolize service. I have to go by the English Civic GL which was called a Contessa or something similar. There are differences. So what seems the same is actually different, not only that but Honda did alter specifications throughout the production run, my GL might be different to your GL. As you stated yours is a two door, Honda Civic GLs were only ever made as 4 door cars. The hatch version is different in specifications. However surely the D15B4 dual Keihin carburetor engine is the same, Maybe? I can feel the fuel flow change at 1850 RPM from a cold start that is the revs that the choke holds the idle accelerator at until choke closure commences and very quickly drops to idle at 850 RPM once warm. The heel and toe dance was common prior to Techron 5000 due to failure to idle as per blocked idle jets, incorrect air pressure to activate strange fuel ratios and all because the choke vacuum operated control and idle wax pellet, which must work in conjuction and one seems to operate the other, which is which? I do not know. Once Techron 5000 did it's stuff and cleared jets, airways, fuel passages, the common cold and whatever else depends on the correct operation of the carburetor, things improved from zero to 100% over nearly three months. It all depends on the extent of blockage, where and of what cause. As I stated, a mechanical fault or actual grit contamination is outside of Techron 5000 to eradicate. My contamination was pretty bad, a lot of precipitate dissolving was required in tiny jets to get any sort of operation, no revs below about 1800 RPM, obviously the high speed jet and fuel starvation over 3000RPM. I actually had no idle jets operational at all.
Seeing as you have a spare twin carburetor set, the gasket, O ring kit is $150, have them rebuilt by a professional, making sure all kit items are installed. As you will do the re bolt on to the manifold and re connect all the hoses, control rods, throttle cable etc make sure you have a new manifold gasket, the old one will be US. Flooding becomes a problem if the idle jet is US, ends result, stalling. The car has become a project, try and enthuse your daughter with the rebuild, she will gain knowledge usefull in many things, one being a rational approach to problem solving.
Good luck Bobval

[bobval]

MKRS
I committed the fatal and unforgivable crime of assuming that the only reference I could locate for the Keihin dual carb was merely two of the single double barrel carbs constructed together. Crap! completely different carbs and never released in the USA, at least not the version we have for the Australian only marketed, ED3 D15B4 Civic GL. In fact our GL differs from all other markets. Seems we got a 9.2:1 compression and the English version was a 9.7:1, it was a D15B variation. The ED3 (ED is European right hand drive designation, Japan had the JDM version also running higher compressions.) was manufactured from late 1987 until final batch for OZ in late 1991. It is referred to as the Civic 1987-1991. Mine is a Japanese manufactured October 1990 model, OZ compliance plated January 1991, sold May 1991. It appears that no workshop manual has ever been released for the Australian version, Honda must have had confidential copies to monopolize service. I have to go by the English Civic GL which was called a Contessa or something similar. There are differences. So what seems the same is actually different, not only that but Honda did alter specifications throughout the production run, my GL might be different to your GL. As you stated yours is a two door, Honda Civic GLs were only ever made as 4 door cars. The hatch version is different in specifications. However surely the D15B4 dual Keihin carburetor engine is the same, Maybe? I can feel the fuel flow change at 1850 RPM from a cold start that is the revs that the choke holds the idle accelerator at until choke closure commences and very quickly drops to idle at 850 RPM once warm. The heel and toe dance was common prior to Techron 5000 due to failure to idle as per blocked idle jets, incorrect air pressure to activate strange fuel ratios and all because the choke vacuum operated control and idle wax pellet, which must work in conjuction and one seems to operate the other, which is which? I do not know. Once Techron 5000 did it's stuff and cleared jets, airways, fuel passages, the common cold and whatever else depends on the correct operation of the carburetor, things improved from zero to 100% over nearly three months. It all depends on the extent of blockage, where and of what cause. As I stated, a mechanical fault or actual grit contamination is outside of Techron 5000 to eradicate. My contamination was pretty bad, a lot of precipitate dissolving was required in tiny jets to get any sort of operation, no revs below about 1800 RPM, obviously the high speed jet and fuel starvation over 3000RPM. I actually had no idle jets operational at all.
Seeing as you have a spare twin carburetor set, the gasket, O ring kit is $150, have them rebuilt by a professional, making sure all kit items are installed. As you will do the re bolt on to the manifold and re connect all the hoses, control rods, throttle cable etc make sure you have a new manifold gasket, the old one will be US. Flooding becomes a problem if the idle jet is US, ends result, stalling. The car has become a project, try and enthuse your daughter with the rebuild, she will gain knowledge usefull in many things, one being a rational approach to problem solving.
Good luck Bobval

[mkrs_adelaide]

Ah, you are forgiven my loyal friend. Lol. Those workshop manual extracts I refer to might explain a few things you raised. The factory workshop manual was hideously expensive, from memory around $1000 for a 600 page bible covering every variant worldwide at the time (1992). Naturally I didn't buy it, but borrowed it from Honda (thankyou Garry Keen) and spent a whole weekend at work on the photocopier.

I can say there were three AUDM variants in 1992. The two door only 1.3 litre breeze, a 1.5 litre GL in both two and four door, and the expensive 1.6 litre Si in two and four door. All totally irrelevant. I was so jealous that the European spec civics were way above ours, some had AWD, they had the VTEC option while we didn't (yet). The manual split the variants into : European Model (2 door), European Model (4 door), Except European Model (2 door) and Except European Model (4 door).

Back to That Which Laughs At Me......Checked the carb 'ECU' in the passenger side footwell. No fault codes blinking at me. BTW, I have all the codes if anyone needs them (for PGM single and dual carb engine) Went back to my spare set of carbs - discovered that the transition jets (low speed jets?) also have a fuel cutout control, but its done by vacuum on little rubber diaphragms from underneath the fuel bowls. It didn't occur two weeks ago that that was what they were for. So.....there's another possible source of blockage. I can check those jets for blockage without removing the carbs.

OK back to it. Cheers Bobval

MKRS

[bobval]

All is explained, you have an EG Civic made from October 1991 up to 1995. The ED Civic is a different beast, no ECU, no electronics, no red lights. Just a mysterious black box designated 36000-PM4-004/87. About ten vacuum lines enter and depart from this box to unknown destinations for unknown purpose. The carburetor depends on all operation from this evil scheme. I even think the carby's are somewhat altered between variants. There seems no manual for the ED3 version in Australia, Honda sat on it for service monopoly. Techron 5000 is still the answer to fuel blockages, irrespective, beyond that it is the junk yard, which was the USA opinion in the 90's. Far too expensive to repair.
Good luck Bobval

[mkrs_adelaide]

I am so cruel, so cruel.....Little honda laughs at me no more. I have crushed its evil black heart and it now idles. Well to be accurate, it no longer stalls.

It took some garden watering system tee pieces and an old vacuum gauge. To explain......There are two vacuum operated throttle controllers on these carbs (like vac advance units on a dizzy). One turns vacuum into a command to increase revs. The other turns vacuum into a command to decrease revs. How handy!!!! What I needed was the ability to turn a dying vacuum into a command to increase revs. So, with gardening watering stuff in hand I rewired the vacuum line to this controller (honda call it the Throttle Controller) directly to manifold vacuum, rather than hose 22 from the depths of hell black box. Then I attacked the throttle controller and sternly said to it, if the manifold vacuum drops below 16 inches of mercury, give the throttle shafts a blip. Thats where the vac gauge came in handy.

And now, when it tries to die, for whatever reason, my dear Throttle Controller gives the carbs a mighty shove up the buttocks. Like, turn on the aircon, lights on, and stand back.......Some poltergeist hops in the car and blips the throttle every five seconds. Revs to 3000 rpm, almost dies, revs to 3000, almost dies......Its pee your pants funny to watch. Aircon off and all seems placid and normal, idle at 1200 rpm.

I'm not game yet to show the car to poor daughter. I think just not mentioning what I've done is the best option here, and hope she never needs to use the aircon. I do think there's a reason not to let engineers loose on something they are not trained on......

I won.....

MKRS

[bobval]

MKRS
See what a little analytical thinking can do, this is the USA solution, disconnect the whole bloody thing and turn it back into a carburetor engine, not an antipollution device. California demanded and got annual or bi annual inspection of the full anti pollution circuit, called smog reduction planning. The Greens would be over the moon in OZ if we still demanded Government green slips every year, with the CO2 police torturing those found to have interfered with Honda's revolutionary unworkable, expensive and virtually non repairable weirdo concept. CVCC was once coupled to a three barrel Keihin carburetor, the third tiny barrel charged a separate combustion chamber in the head which in turn fired off the main ignition from a vortex modified inlet fuel mixture running around 20:1. All of this coupled to the weirdo carburetor and fed into a catalystic converter might have reduced carbon emissions by 0.0001%. No other manufacturer bothered to emulate Honda having seen the labour costs involved in endless ongoing service. Honda may have designed a mathematical marvel but their engineers had no concept of real world labour costs. Slavery had by this time ceased in the western world and car owners demanded fully qualified TAFE trained mechanics who do not come cheap. India and the Philippines along with China and all of Asia in the 1980's was still a dollar a day workforce. In my desperation prior to Techron 5000 discovery, I had contemplated much the same thing, it was listed on a USA web site. Now all you must do is continue with diagnosis and realize that disconnection of vacuum lines is not really the ideal solution, the solution is to discover where and why the vacuum lines are not doing as intended and that will invariably be due to blocked jets disrupting vacuum creation. (or something like this, I do not have a Honda degree in advanced math nor design philosophy) Like Honda did by 1995, they ceased manufacture and retention of a nightmare system that had the now rapidly concerned car buyer looking elsewhere. Vtech cams linked to Keihin's with CVCC heads became even worse as far as reliability and service was concerned. All new cars are great for the first hundred thousand kilometers, no self respecting buyer holds one over 60,000 anyway so who cared, not Honda, their cars were designed for the crusher at 100,000 miles. Second hand buyers do not rate. iVtech is a bit of an over statement, most city or suburban cars will rarely invoke the throttle demand necessary to switch to iTech high lift cams. For fuel economy buy a gutless 1.3 lt box, for performance and torque at 6000+RPM do the right thing and get a car designed to provide that, all from a big 6 cylinders, preferably normally aspirated, no supercharger or turbo induction that costs even more to run and maintain for useless power output at revs one will never see. Porches can do 180 Kph, so can speed camera's and low flying highway patrol Cessna 210 aircraft, either way the days of speed are over other than in the hands of race drivers.
Good Luck, I get more anti Honda daily, Honda sales are collapsing world wide due to high service costs and overly involved technology, drivers now want a return to simple low maintenance cost vehicles with reasonable fuel economy not the smell of an oily rag turbo rev boxes that must soon have combination locked bonnets as there is nothing under there even remotely serviceable outside of a specialized dealership. Toyota saw the light, GM and Ford also, keep the cost and frequency of service and maintenance down and the world will beat a path to your door (something to do with mousetraps or Henry Ford I am sure)
Bobval

[mkrs_adelaide]

Hi Bobval, i tried to do a post yesterday but it was quarantined by the word watcher I think. Never mind. Looks like we have divergent views on automotive technology. I'm an ardent fan of Direct Injection turbo petrol, and oddly, hybrids. I hope Honda jump on board the DI-turbo petrol bandwagon, have a look what powers the little A class Merc called the A45. 265kW from two litres. VW are also masters of this technology, and its becoming the new standard in performance with high fuel efficiency. ( Sorry, the engineer comes out again) I know honda are masters of hybrids. Sort of...

Finally, and this might be my last post unless the civic does something really bizarre, my two cents on hybrid cars.

Hybrids are still built the wrong way round. They are basically a petrol car with electric assist. It helps, a lot, but its still pussyfooting. These hybrids, fuel economy wise, are barely better than a well sorted turbo diesel, and the DI-turbo petrols are catching up. What the hybrids need is a reversal of priority in the drive train. If you make the hybrid cars electric drive BUT with onboard power generation from an efficient fuel engine, you will get the best of both worlds. For exampl, a hybrid camry would be able to do open road speeds and get better than 100mpg, because the little engine charging the batteries would only run at its peak efficiency, putting out what is the Average power needs of the car. And at 100kph, reasonably slippery cars use less than 10kW. All the technology is out there already. The MKRS approach would be to modularise the onboard charger and battery systems, so a buyer could pick the best options for their needs. Want a bigger charger sir?, certainly. The 20kW charger option will reduce your average fuel economy a little, but Sir would be able to get from Melb to Sydney two hours faster.

Ok, ok, its just a pet idea I've had since the 80's.

All the best everyone.

MKRS

[bobval]

MKRS
I do agree with the concept of hydbrids, though I think it is the battery weight that is determining the choice of main power unit. I note from reading that some manufacturers do indeed vary the dual unit output choices. Did a bit of research on the internet description of Civic 1987-91 ED3 and the Civic 91-93 EG. Different engine, Yep both are 4 cylinder and ruled by the Keihin dual barrell carby but much else is quite different. I will attempt to send a picture of the ED3 D15B4 instalation. Perusal will reveal only the left carby has a choke vacuum operated diaphram. As there is no ECU, nothing relating to carby operation could be similar for both engines. The Poms had a variant in 1990, seemingly much the same as a D15B4 except that it was a D14B2. Once Vtech and injectors were installed everything went out the door. The AU variants were very much a parts bin job, no one else ever got the combination of engine crap we we given. The Yanks had only injection from late 1987, no carby ever to disgrace the Honda name again, The UK followed suit in late 1990. I still consider techno zap turbo motor bike engine cars pushing out massive revs to get any sort of torque as irrelevant. Mercedes have indeed developed these engines, though for what use I cannot understand. An A 160 will suit the suburbs nicely thank you. Cars under 1300 Kilograms do not need more. Now racing cars! that' different. My posts are all about 72 KW Honda Civics, nowdays the 72KW has gone up to 88KW for the Jazz which is about 100Kilo more than the poor old ED3 at 1026Kgs. Power to weight difference is less than the 16 KW increase. Torque in the low to mid rev range is much higher, that is the main improvement. Thing is 72KW for the ED3 D15B4 is at 6200 Rpm, Torque is at 4300rpm. Now who is going to rev up to 6200 or higher on a public suburban street? I can hold 100 Kmph at 3100 rpm in 5th gear which is the highway limit. A short burst to 4000 rpm gives me 110KMPH + for overtaking Murray's interstate bus. Hopeless at this inet stuff so maybe no picture.
Bobval

[mkrs_adelaide]

Bobval. i wasn't going to drift away from the core subject any more but your few words on turbo petrol high revving engines just deserved a response. These new tech engines are phenomenal by virtue of their resistance to detonation. They run impossibly high compression ratios, impossibly high boost pressures and are anything but all or nothing high revvers. I think the flag carrier of this technology is the entry level Golf. I have a personal issue with such small capacity petrol engines but the world loves them.

So, come on Bobval, be nice to them. We are too old to service them ourselves anyways.

Your comment on battery weights in hybrids is valid. I did some hybrid surfing after my little rant above and feel a little sheepish. OK, the Volt is the sort of vehicle I'm talking about. BUT. BUT. Whats the go with such a powerful on-board charger?? (63kW) Be braaaaaave. Put in less powerful charging, improve efficiency with a turbo on that DI petrol engine, lighten the thing up 200kgs. I don't know, maybe people just lurve the idea of zero MPG, using just electrons. I still maintain my recipe will give better economy, if you can get away from plugging the thing in every night. No more on hybrids, I promise.

The Civic got a run at the hands of my dear P plater daughter. Man I love that car. I call my mod to the carbs "stall arrest". If she does a crappe take off and lets the clutch out too fast for the revs, the poltergeist jumps in and shoves the throttle down. And off the car goes. Idles a bit fast and with a miss, but I'll sort that out in time.

I'm off. Back to dreaming about what engine to slot into the 240 zed. Cheers!

MKRS

[bobval]

MKRS
I think we had best kill this discussion, I guess the moderator is getting pissed off. The turbo tech zap screamers all of 1 litre running at near 12:1 compression, 20,000 rpm in the turbo at boost pressure equal to a bomb are also virtually impossible to service or maintain in Australia. The cost of maintenance is horrific, if a skilled reliable technician can be found. The general rule is to chuck out the original of anything and stick in a new one, no one can fix it economically. None of these new contraptions have hit 10 years old as yet, then it will be a different story. A ferrari is bad enough, Canberra owners send them to Ferrari in Sydney for service. There a plenty of Ferrari models in Canberra. Very few new car buyers will touch the turbo zaps, sales are negligible. Me! I once had a 4.1 lt big 6 old Ford Falcon, slow revving, big on torque, low on output , lousy on fuel but never, ever, needed service beyond oil and plugs. Cost nothing to run, that is the sort of car needed for OZ, still plenty of them doing the suburban run here. Fuel costs are irrelevant in a country area, no slow traffic, no stop/starts, fewer traffic lights, and much shorter daily journeys. I average less than 200km a month, a 6.2 lt V8 would not matter and neither does it matter to many others, V8s are common here also, even with 91 RON at $1.57. Now a friend has a hydbrid Toyota, very impressed, so quite I thought it had no engine, what shove from 10-50 kmph. He has taken it to Tasmania twice, fuel economy around 4ts per 100kms to nothing to charge the battery and run up a hill. I would consider buying one of these if I needed a new car. Though the lighter the car the more uncomfortable, in the bush, impractically so! Keep working on the Civic EG, you will discover the vacuum leak soon enough for it is now certain to be both fuel and air passage blockages plus, a, or several, vacuum line leaks, at the connections I guess and invariably deteriorated rubber hoses underneath the screw clip where it can not be readily seen and makes you thing the hose is OK. No hose is OK until a vacuum gauge says so. I have the full diagrams showing the procedures. I actually did what you have done to the EG on an older 1980 single carb Accord, put a ball bearing in one vacuum line, connected the other to the vacuum advance, ran an auto idle throttle advance, worked in a fashion. Look up the ED3 D15B4 under the English web site for Honda, the workshop manual is listed in part for a version as 1.6 or 1.4 both had the Keihin dual carby and the vacuum tests are illustrated. Good luck and so long! Bobval

[.Dave]

Lol wtf

[mkrs_adelaide]

Hi all. Just a quick note to report that the daughters problem with the twin carbs has been fixed. The carbs were rebuilt here in Adelaide, not by me, but by a mechanic who knew about these carbs.

Its never run so smoothly in its life. They even fixed the too-fast cold idle. Hate to think what it cost to rebuild.

Thats all. Cheers Bobval.

MKRS

[bobval]

MKRS
Congratulations! There are many things in this world best left to the experts, ie one who actually does have experience and detailed knowledge of work to be undertaken. The strip, clean, rebuild was really only ever going to be the answer. During the course of the rebuild, vacuum lines, needle valve settings and a plethora of associated fault inducing items would have been fixed. Hope the EF has another 100,000 Ks left in it. I have since examined all vacuum lines and looked inside the black box, the ED3 is different from the latter EF, I have a three solinoid vacuum controller in place of your system, all is AOK and looks new, never been left in the open, temperature controlled. no rust, tarnish or signs of corrosion.
Bobval