please help ASAP my car is bucking

[goldadition]

i have a 87 dx 5spd 190k

i have replaced the plugs, wires, cap, both f.f. all within 9 months
the vacum lines within the last 5 years.
it only bucks when the car is nice and hot, one hour run time at least. please help i need my car asap

[A20A1]

What do you mean? Is it a buck at idle? or a buck when you try to accelerate?


1) What octane do you run

2) Have you fooled around with ignition advance... for example turning the distributor

3) If it's on acceleration my guess is that it might be a loose booster venturi

4) Other things like fuel filter and spark plugs may need to be inspected and or replaced.

5) How is your coolant and oil? What Weight of Oil do you use... this concerns me because you said it happens once the car is hot.

[A20A1]

When inspecting the spark plugs make sure you note which cylinder the plug came from and if the plug it white / black / oily / broken, damaged, etc.

[goldadition]

it bucks when i accelerate and at idle it runs but VERY rough. i usually run 93 octane. i havn't messed with the ignition at all.
where is the booster venturi? what is it? any idea of how to tell if this is the problem. the oil is at the normal level. i use 10w30

[RustyHo88]

have you pulled off the air cleaner housing lately? if so, you may have loosened one of those little vaccum hoses underneath the air cleaner housing. the problem your explaining happened when i removed the houseing, it turned out to be one of the hoses on the passanger side of the housing. it was connected to a three way hose splitter, a little orange thingy. i realize you have replaced all the vacuum hoses, but its worth a shot.

[1988starter]

Try getting out the carb cleaner

[zero.counter]

Its sounds odd and I usually suggest, but have you checked your fuel filters for clogging. Also the PCV valve, dirty air filter, distributor timing, arcing in the spark plug cables, incorrect gaps in the spark plugs and/or bad, bad ignition coil, and even a faulty fuel pump. The carb choke cleaner will sometimes clean the gunk which help tremendously

[A20A1]

Yeah I agree with rusty about the hose to the check valve, and other hoses under the air cleaner.

I'll look for the link. To show you how to find and fix a loose booster venturi if it is the problem

http://www.3geez.com/showthread.php?s=&threadid=8972

[Mike's89AccordLX]

How is your idle (what rpms?) Maybe you need to adjust the carb. A/F and Idle.

[A20A1]

If it was a bad idle then I would go to a fuel or igniton related problem... all of which can be caused by a vacuum leak.

Tricky Tricky...

It's a lot easier to fix a car when you can drive it and hear it run.

[Mike's89AccordLX]

I know what would be cool and work good. 3GEEZ should manufacture a mini A20A1 (user not the engine) so that whenever someone has a problem with carbs he would be in the tool box. hehehe

The problem can be many things. Just start with the cheapest and work up from there.

[A20A1]

:lol... That would get annoying... plus the carbs of the world would get all sorts of funky mods done to them, since we'd come out to play and tinker at night.

[1988starter]

Originally posted by A20A1
:lol... That would get annoying... plus the carbs of the world would get all sorts of funky mods done to them, since we'd come out to play and tinker at night.

So true and it would be very bad in emissions controll states.

[goldadition]

thanks for the tips guys! i'm going to go check the f.f. and the vacuum lines. the car idles VERY rough; but it's only after an hour of run time. it purrs like a tiger before the first hour. very very confusing! i'm going to go get some carb cleaner also. thanks again.

[Aarie$$oul]

What is bucking?

[goldadition]

ok i just was looking at the f.f. by the gas pump. it looks like a big sock. any way i have noticed that my new filter doesn't have the clip that i would used to bolt it on. also i found out that in order for me to get a new clip, i would have to buy a brand new fuel pump from the dealer. this sucks!!!!! if you have any suggestions on where to get a clip that would fit it would be greatly appriciated.

[BootMachine]

Yo...my Prelude used to buck like a MAD ASSHOLE....it bucked HARD.

Only when it was hot the engine would all of a sudden suck and idle rough like it had a hot cam in it or something...when I acceled the bucking would start. I would push in the clutch 1/2 way to dampen the bucking and then as soon as I hit 4000 rpm it would stop.

Turned out it was a combination of problems. First the ignition timing was floating because my dist. chewed itself apart. They are 900 bucks CAD from Honda but I can get them for 400 CAD if you need.

Second...was the throttle angle sensor...it was gone...I punked one from a junkyard and my code seven was gone (this is a FI A20A engine I'm talking about here)

Third it was the oxygen sensor...replaced it and the bucking has stopped and my ecu is dark..no blinking!

What was happening was the engine getting confused from all the BS signal comming from the broken sensors so the ECU was running the mixture lean and then rich back and fourth causing my engine to BUCK in the bay....so hard to drive when it bucks!

[rocky2]

Your choke wire fell off. Take off air cleaner. Start engine...Let idle...inspect butterfly....it should open at some point when temp gauge gets in center postion anyway.