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.
First post from a newbie. Regarding d15b4 twin carbies
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.
civic ed3 d15b4 twin carbs
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.
civic ed3 d15b4 twin carbs
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!.
civic ed3 d15b4 dual carbs
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
civic ed3 d15b4 dual carbs
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
civic ed3 d15b4 dual carb
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
civic ed3 d15b4 dual carb
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
civic ed3 d15b4 dual carbs
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
The Civic finally got fixed!
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