87 Accord won't idle properly??

[FIVE 7]

I have an 87 Accord, A20A2 Carbed that won't idle smoothly at low idle. It is like a miss but not as bad as a miss....more like a lope, but only at low idle. It won't stall or die, but it shakes, once you are at a light or are ideling it. Once you take up the rpm's, it smoothes out or maybe I don't hear it as much. I pulled each wire off, one at a time and it misses on all but 1 plug wire. Not sure about this but it is the second one from the left? I checked each wire with an extra plug I had and each wire seems to be producing a spark. lNew: Plugs, Wires, Air Fiilter, Fuel Filter, recent cap and rotor and PCV Valve. Car runs great and seems to have lots of go, aside that it eats gas (still working on that). Does anyone have any suggestions? Maybe a vacumm leak?

Thanks,

Brent

[A20A1]

Yeah check how much vacuum you are pulling... when the car is cold and when the car warms up fully.

[RamThis]

If you pulled a plug wire off of a cylinder while it was running, and you got NO CHANGE in the motor, then something is definitely wrong!!! There should be a noticible drop in RPM, it should run rough as well. If you havent already, pull that plug and check the gap and color to see if its getting proper combustion. You could have a blown head gasket on that cylinder, our a stuck valve, or bad rings. The plug in that cylinder could also just be defective, like a cracked insulator or the electrode insulator could be broken up in the threaded base allowing it to slide down and shield the spark gap (had this one happen to me on my truck, only caused a problem at idle as the increased RPM blew the insulator back up into the plug body and it fired fine then.)

Do a compression check on that cylinder too. Id be willing to bet youll find something odd about it.

[FIVE 7]

I replaced the plug and it made no difference. All plugs are new and properly gapped. There was only one cyclinder that didn't make a difference when I pulled the wire off and that was the second one from the left when looking at the front of the engine. Will do a compression check soon. What about this vacuum check that you are talking about...when it is hot and when it is cold. Can you explain what and where to check for this? Is this the vacuum advance line off of the distributor?

Thanks in advance.....

Brent

[A20A1]

it's simply a vacuum gauge connected to the intake manifold or some other spare vacuum port to get a reading of how much vacuum you're pulling.

[FIVE 7]

Do you think if you get a chance, that you might be able to explain to me how to check for this step by step.

Thanks alot, I appreciate it.

Brent

[russiankid]

what kind of plugs are you running? it could be the plugs, or maybe even plug gapping, need more info.

[A20A1]

Do you think if you get a chance, that you might be able to explain to me how to check for this step by step.
Thanks alot, I appreciate it.
Brent

https://www.3geez.com/showthread.php?t=46754
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[FIVE 7]

Plugs are NGK, I believe BPR 5EY-11, gap set at .0042". I also remember when I had the air cleaner off, when I plugged the vacuum port that normally connects up to the diaphragm for the cold/warm air flapper in the air cleaner, the idel smoothed out somewhat. Could this diaphragm not be working? Is the best way to check for this when the engine is cold, look in the snorkle, start it up and see if that flap closes? Just takin stabes at this right now.

Thanks,

Brent

[smufguy]

always the Cyl 1 starts from the crank side. so the second cyl from the left would be the 3rd cyl from your crank side. so its the 3rd Cylinder. (this applies only for inline motors btw).

BPR11s sounds out of the range recom for the carb. Its either a BPR16 or BPR17 is what you need for your motor.

Its really interesting how you get spark from your wires for that cylinder, but u dont seem to be firing.

[VTEC_Inside]

That "Hot air door" diaphragm is notorious for going bad. I'm using the better of two that I have, lol...

You can plug that line temporarily and see if it cures your problem. If it does, try to replace that diaphragm. Or if you live in a warmer climate just leave it plugged as I believe that vacuum is what closes off the intake in this case.

[russiankid]

im not sure what this is called, but when you look at the engine bay from standing in front of the radiator, behind the vavle cover, like right behind it, there is a vavle, or w/e its called, it has a vacuum line running from it to the carb, unplug that and plug it up with a screw, you dont need unless you need to pass emissions, but my car passed without it being hooked up, that valve or w/e could no be working properly causing bad idle, this helped my idle problem on my car, also cleaning the carb with special gas tank treatment, and using carb cleaner spray, when the engine is running rev it to about 2k or 2500, have somone hold it there, while you spray that carb

[A20A1]

The air suction valve.

The egr valve is the next valve over to the left.

[russiankid]

The air suction valve.

The egr valve is the next valve over to the left.

yea i think its the air sution valve

[FIVE 7]

Air Suction Valve, thanks guys....I'll have a look tomorrow. Just not sure why all of a sudden it would start to idle roughly? "Hot Air Door" seems to be working ....started it up first thing this morning and it opened up when I looked in the snorkel of the air cleaner.

Keep tryin.....

[russiankid]

because it could of just started to work improperly, or even just stopped working

[FIVE 7]

Well, I figured out what the problem was....a leaking intake manifold. Time to replace the gasket.

Thanks to all for their help and suggestions.

Brent