fuel, vacuum or carb problem?

[rehv_Aerodeck86]

ok ..this has pissed me off for 3 months now - car doesn't idle like it should when warm : after releasing the pedal, rpm falls and car usually dies in 3 seconds..someties it's suffering @ 300-400 rpm for 6-10 seconds and then dies. I have to press the gas pedal to keep it alive.It's especially weak, when i'm sitting behind the traffic lights and revving up my shitty stock 3g like a n00bass ricer who wants to beat the BMW 535 waiting next to me.

Even when i try to hold it still @ 1000, rpm varies from 800-1200. When engine is cold, it works very steadily and nice @ 2500rpm, then 1500rpm.

Also this is happening: when i floor my 3g on the road, it pulls my ass off, but when it wants to go over 3000 rpm or so, car wants to die...like it's out of gas..and an assload of black smoke comes out of muffler if i keep th epedal down. akfter releasing the pedal or pressing it gently it drives on like normal. I'f i'm accelerating like a 70-year old nut, it goes nicely to 3500rpm
This especially pissy off, when i want to drive pass somebody, and when i'm next to them car starts bitching and i have to cancel my attempt and pull over for 1 minute and let the car rest

I'f i'm floor the pedal while idle'ing, it goes nicely and fast upto 8000rpm or so...no problems..and comes down..to 0 rpm if i release the pedal

So any ideas wtf is wrong with it?

Info about my 3g:

'86 Aerodeck ,A20A2 engine, vaccuum removed 1 year ago (worked fine after this setup ~9 months so nothing wrong with that), no air filter or airbox at the moment, no cat, empty muffler, stock engine, shitty old plug wires

Things i have checked or replaced:
*new NGK-r plugs,
*new fuel filters,
*cleaned the carb (maybe i did it wrong and vacuum is leaking from the seal?)
*checked for vaccuum leaks but didn't find any,
*checked the radiator and coolant = they're working and engine doesnt overheat,
* checked choke plate = this opens like it should
* checked venturies = they're tight and dont move

So what's this: is my fuel rail or fuel pump crappy? is it a vacuum related thing? I have no ideas

So any help would be appriciated ,guys.

['89AccordLX(Rus)]

It sounds like the engine is not getting a consistent fuel flow. Since you replaced the filters already, try finding a used fuel pump and swap it in place of your old one. If the problem disappears, then the old pump was getting weak. Also, black smoke is an indication of running rich. In turn running too rich will cause the engine to bog down as you are describing. This is usually caused by incorrect carb adjustment, or weak ignition. You mentioned that your plug wires were old. Try changing them along with the cap and rotor. Weak ignition may cause incomplete combustion resulting in a poorly running engine. Furthermore, since you removed the vacuum lines already, try checking whatever vacuum lines are still left for cracks and leaks. Replace them if needed. Check the big fat vacuum line going to the brake booster as well to make sure that it isn't leaking. Also, above 3500rpm your secondary throttle barrel should open. It is vacuum operated. Since your car works fine up until that point, check the secondary mechanisms as well (check out the shop manual at http://www.pauldesign.ru/).

[rehv_Aerodeck86]

thanks for informative reply, man i'll try another fuel pump and a new hose too.

i forgot to mention, thet already did the manual secondary too, and this is working perfectly . thx A20A1 also checked rotor and dizzy cap...nice and clean.

oh...half of the time i'm driving, i can smell strong gas smell....in the mornings especially i doubt if to light the cigarette or not

['89AccordLX(Rus)]

thanks for informative reply, man i'll try another fuel pump and a new hose too.

i forgot to mention, thet already did the manual secondary too, and this is working perfectly . thx A20A1 also checked rotor and dizzy cap...nice and clean.

oh...half of the time i'm driving, i can smell strong gas smell....in the mornings especially i doubt if to light the cigarette or not

If you smell gas, take a look at the charcoal canister that is mounted toward the passenger side of the firewall. It has vacuum operated valves which may be malfunctioning or leaking. Also, are there any gas leaks in the carb area? Wet spots? Has the car sat for a while without being used? Gasoline will gum up in the carburator and restrict fuel flow or block passages completely. If the vacuum lines check out OK and the fuel pump doesn't fix anything, you may need to rebuild the carburator. There is a HOW-TO available with many pictures and explanations for that procedure. And I know that you stated that the choke is openning correctly, but are you sure it goes completely vertical once it is warmed up? There is also an air-jet controller mounted close to the carb. If you still have it connected, check those lines as well. Since the car worked well for 9 months before this started happening, its probably something that can break spontatneously (fuel pump, vacuum lines, diaphragms, etc.). A tired carb will not fail immediately, but usually just get progressively worse. Just my $.02

P.S.: My car has a similar idle problem as yours, except mine happens in cold weather during start-up. The idle is super low but it runs. Once the choke unloader coil warms up, it is fine.

[racerx]

here's a few suggestions:

check your choke plate. when it's cold, it should be closed. as it warms up, it should open to fully straight up and down. if it's not, then that's your problem.

if that's not it, check your EGR. if it is not connected or not working correctly, it will cause the engine to stammer and studder in low rpms. in the higher rpms though (4000-redline) it should smooth out and run strong.
if your engine acts like that, then it is definately your egr. I thought disconnecting it was a good idea once, then about a month later the car was acting all facked up! it was the egr.

[lanman024]

choke plate might be it happened to me, fixed it now runs fine

[rehv_Aerodeck86]

choke is working fine btw... and i think i have no EGR (because i have european model). weird...

i spoke to a local machanic and he said maybe the float level is too low in the carburator. is this possible?

[AccordAddict]

ok ..this has pissed me off for 3 months now - car doesn't idle like it should when warm : after releasing the pedal, rpm falls and car usually dies in 3 seconds..someties it's suffering @ 300-400 rpm for 6-10 seconds and then dies. I have to press the gas pedal to keep it alive.It's especially weak, when i'm sitting behind the traffic lights and revving up my shitty stock 3g like a n00bass ricer who wants to beat the BMW 535 waiting next to me.

Even when i try to hold it still @ 1000, rpm varies from 800-1200. When engine is cold, it works very steadily and nice @ 2500rpm, then 1500rpm.

Also this is happening: when i floor my 3g on the road, it pulls my ass off, but when it wants to go over 3000 rpm or so, car wants to die...like it's out of gas..and an assload of black smoke comes out of muffler if i keep th epedal down. akfter releasing the pedal or pressing it gently it drives on like normal. I'f i'm accelerating like a 70-year old nut, it goes nicely to 3500rpm
This especially pissy off, when i want to drive pass somebody, and when i'm next to them car starts bitching and i have to cancel my attempt and pull over for 1 minute and let the car rest

I'f i'm floor the pedal while idle'ing, it goes nicely and fast upto 8000rpm or so...no problems..and comes down..to 0 rpm if i release the pedal

So any ideas wtf is wrong with it?

Info about my 3g:

'86 Aerodeck ,A20A2 engine, vaccuum removed 1 year ago (worked fine after this setup ~9 months so nothing wrong with that), no air filter or airbox at the moment, no cat, empty muffler, stock engine, shitty old plug wires

Things i have checked or replaced:
*new NGK-r plugs,
*new fuel filters,
*cleaned the carb (maybe i did it wrong and vacuum is leaking from the seal?)
*checked for vaccuum leaks but didn't find any,
*checked the radiator and coolant = they're working and engine doesnt overheat,
* checked choke plate = this opens like it should
* checked venturies = they're tight and dont move

So what's this: is my fuel rail or fuel pump crappy? is it a vacuum related thing? I have no ideas

So any help would be appriciated ,guys.

Ummmmmmmmm... if your reving it to 8 grand, that probably caused a problem right there....

['89AccordLX(Rus)]

choke is working fine btw... and i think i have no EGR (because i have european model). weird...

i spoke to a local machanic and he said maybe the float level is too low in the carburator. is this possible?

If your float level was too low, you would experience a lean condition, lack of fuel, etc. Instead, you are getting clouds of black smoke, which usually indicates a very rich mixture. Try rebuilding the carburator or replacing it with a rebuilt one if all else fails. Also, did the car gradually get worse and worse, or did it just start happening all of a sudden? Have you messed with the mixture screw? There have been posts about the screw falling out causing a poorly running engine.
Here is a thread explaining the problem: https://www.3geez.com/showthread.php?t=32613

Hope this helps you.

[rehv_Aerodeck86]

no i havent touched the mixture screw..or anything adjustable things got gradually worse afaik. at th emoment i took off the carb and i'm messing with it in my room . i've got a shitty spare carb sitting in the garage...maybe i can take best of both worlds and get it to work somehow.

thanks a lot guys...especially '89AccordLX(Rus) for taking ur time. i'll write tomorrow how things are going

[rehv_Aerodeck86]

omfg... i rebuilt the carb, checked the vacuum lines and replaced broken ones. still nothing. car doesnt idle at all. if i pump the pedal and try to hold it steady, rmp's go up and down. and on they highway....again over 3500rpm is starts to stuggle and make black smoke farts. damn... what's her problem. can a faulty fuel pump or jammed fule line do all this headache? cause when i floor her in the city it runs like a champ....until 3500. and NO IDLE :

[A20A1]

maybe your egr valve is stuck open?

also might want to see if your top hat gasket isn't sealing porperly, becasue if the air bleed jets or air jet controller ports get vacuum when they are not supposed to then you'll end up sucking fuel into those ports and messing up the mixture...

Also I read something about some carbs coming with a powervalve control solenoid... but the valve opener itself still should be fine operating on just manifold vacuum.

[rehv_Aerodeck86]

damn.. i'm not sure that i have an EGR valve. :S can smb tell me by the pic?




another suspicios thing: i noticed taht the intake manifold is shitty. is there an explanation for this or is it just dirt or oil ? .



and pcv valve is also weird. it doesn't seal properly, pipe is cracked. i also plugged the manifold pcv valve port on the manifold for testing , but no difference.

[A20A1]

No you have no EGR, interesting, that's probably why they seal off one of the ABC ports for the air jet controller from the factory... to richen the mixture and keep the car from pinging.

Hmm it looks like you left a vacuum line unplugged, close to where #25 and #2 is?

Also about the PCV thing the valve needs to work and be connected and hopefuly you can fix the leak.

did you plug all the ports not connected to anything... on the carb?

[rehv_Aerodeck86]

yep, plugged all open carb ports. the rail near to 2 and 25 is just an empty rail, both ends are open.
i just called local honda service, and they thought it's carb problem - ".....air leak or sth, if was fuel rail or tank problem, u would feel great lack of power while driving..." ..but i dont. car runs very finr til 3500rpm. i want my bitch at least idling can it be the carb upper gasket problem?
is A/F screw adjusting a must after vac. lines removal?

thx


p.s here's my vacuum setup:

[A20A1]

yep, plugged all open carb ports. the rail near to 2 and 25 is just an empty rail, both ends are open.
i just called local honda service, and they thought it's carb problem - ".....air leak or sth, if was fuel rail or tank problem, u would feel great lack of power while driving..." ..but i dont. car runs very finr til 3500rpm. i want my bitch at least idling can it be the carb upper gasket problem?
is A/F screw adjusting a must after vac. lines removal?
thx
p.s here's my vacuum setup:

#2 and #25 are both connected to manifold vacuum then? don't worry about that diagram, I forgot to add in the connection for #25... I added the newest diagram that shows the actual routing for #25... but if you don't have the parts needed then just leave both to manifold vacuum. Thermovalve A removed.

I just found a site online... but I'll post on that in offtopic

can you remove the top hat and check the gasket... but do one more thing... try to pull up on the booster venturies... with the top hat removed you may be able to move them whereas with the top hat on they were somewhat tight...

your vacuum secondary is manual right... I doubt it could be misalligned... as long as you used the parts on the diagram it should open very close to the correct time.

[rehv_Aerodeck86]

yes man, ur mechanical secondary works like a japanese watch =).

well actually line nr 25 isnt connected to man. vacuum :/ i have both 3-port thermovalves down there (driver side of maifold...like here on schematic A.3
https://www.3geez.com/attachment.php?...tid=3363&stc=1). ..so line #25 is connected there.
manifold vacuum is on passanger side of manifold (u can see from my pics).

i removed the carb head couple of times an dchecked the gasket. it's nor perfect though. should i check it for leaks by sprayng carb cleaner while running?


and what do mean by this : "try to pull up on the booster venturies... with the top hat removed you may be able to move them whereas with the top hat on they were somewhat tight..." ? i dont get it. u mean i remove the carb head and check the venturies? sry my crappy english

[A20A1]

yeah just the top part of the carb so you can see inside the float bowl...

do the carb cleaner check for sure.

[rehv_Aerodeck86]

ok... i'll fetch some tomorrow and give it a try.

1 more idea: can it be spark plug wires? cause 2 of them are crappy replacement from the jukyard, other two are quite new bosch's. maybe give them a check with a multimeter? afaik resistance should be <25000 ohm ?

[accordlxi2.0]

2300-2500 around there.
if it was then the engine would idle but would shake, plus when you accelerate it would putt-putt.

['89AccordLX(Rus)]

Take a look at your wires in the dark. If you see flashes of light/sparks, the insulation is worn and the wires need to be replaced. I am not sure what the resistance on the wires should be, but you might as well change them. They shouldn't be very expensive and since they are the only part of the ignition system that you haven't looked at yet, they may be causing trouble. Check those simple things first.

[Mr_SARS]

Hey, I've been floating around the forums for a couple weeks now, but I just had to register to reply to this post.

I've been having the same problem as you rehv_Aerodeck86. I've tried changing the spark plugs, the spark plug wires, the fuel filter, and the fuel pump with no success...I know nothing about carbs so I won't touch mine, but if anyone else has more ideas give me a shout!

[Civvy]

have u got a cylinder off? try pulling each lead off one at a time whilst the engines at idle.
Sticking valve(s)?
Have you changed anything to it recently??
compression test?

[Civvy]

Whats your plugs like?

['89AccordLX(Rus)]

Hey, I've been floating around the forums for a couple weeks now, but I just had to register to reply to this post.

I've been having the same problem as you rehv_Aerodeck86. I've tried changing the spark plugs, the spark plug wires, the fuel filter, and the fuel pump with no success...I know nothing about carbs so I won't touch mine, but if anyone else has more ideas give me a shout!

You pretty much eliminated all the possible trouble areas except the carburator vacuum lines and the carburator itself. The vacuum lines are relatively easy to check. Any cracked or torn lines need to be replaced. You can use carburator cleaner spray to detect vacuum leaks. All you do is spray the cleaner on a certain section of hose(s) and if the engine picks up, there is a vacuum leak in that area. Since you are doubtful about your carburator diagnosing, you can either buy a rebuilt carburator or get a spare used one and rebuild it yourself. If you screw something up, you still have your original carburator as a back up. Hope this helps.