Civic ed3 d15b4 dual carbs

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.

Hi Bob

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

Got any pictures of your ED3?

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.

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.

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.

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.

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.

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

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

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

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.

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.