Rough Idle on 88 Accord

I have an 88 Accord LX (carburetor) with roughly 183,000 miles on it.
I recently gave it a tune-up, including replacing the spark plugs and
wires, distributor and rotor, air cleaner, BOTH fuel filters, and the
PCV valve. It starts up just fine, and then after it warms up, when i
come to a stop light or something, the idle goes down to about 500
RPM's or so and the car shakes a lot. The gas mileage has gotten to be
really bad too. I don't know what could be causing it. I've checked
most of the vacuum lines with a hand pump (haven't sprayed anything on
all of them though to see if the idle goes up). I've heard that it
might be anything from the carburetor to the cat. converter. I just
want to get the dang thing fixed. PLEASE HELP!!!

P.S. - After thought. After I have been driving it for a while and
park it to go into the store or something, when I come back out, it is
most of the time harder to start than when cold and sometimes wont
even start at all. That's why I have been told that maybe it is the
cat. converter blocking up the system. I don't know.

 

Hi,
Spraying WD40 is handy for vacuum leak check.

 

Was this happening before the tuneup? Are the new plugs, wires, and
dizzy parts OEM?

After warmup is when the oxygen sensor kicks in. So apart from needing
OEM ignition parts, a strong candidate cause of this problem is a
malfunctioning oxygen sensor. Go to www.densoproducts.com and get the
Denso part number for your car's O2 sensor. Either buy it there or go
on Amazon or Ebay to buy a Denso (= OEM) one. It will cost you not
more than $30 right now plus shipping and handling.

 

It sorta sounds like it could be a catylitic converter assuming that it
is still the orignial. Loss of power after reaching operating
temperature is a classic symptom of a clogged cat.

Spraying the area of vacuum lines with carb cleaner can often pinpoint
vacuum leaks.

Before that I might suggest a bottle of Techron as it can do wonders for
a carburetor that is otherwise undamaged. Fuel filter(s) change would
also be in order.

HTH

JT

 

Well it was running pretty rough before the tune up, which is the
reason why I gave it a tune up. I used parts from NAPA, so I assume
that they are good. The oxygen sensor was also replaced at the same
time. I will check to make sure that it is the right one.

 

Yeah the catalytic converter is the original one that was on the car.
I've heard that is what could be my problem. I am going to look to see
i it is clogged. I am also going to check the vacuum lines AGAIN to
make sure that I didn't miss anything first. I will get some carb
leaner to do that.

thanx

 

Yeah the catalytic converter is the original one that was on the car.
I've heard that is what could be my problem. I am going to look to see
i it is clogged. I am also going to check the vacuum lines AGAIN to
make sure that I didn't miss anything first. I will get some carb
leaner to do that.

The Haynes manual for my daughter's '93 Accord has an interesting way to
check for exhaust restrictions, such as plugged catalytic converters.
Basically:
*connect a manifold vacuum guage to the intake manifold
*start the engine and let it warm up if necessary
*note the idle reading
*rev the engine to around 2000 rpm for a few seconds and note the reading
*watch the guage when you let go of the throttle.

The guage should return to the idle reading within about two seconds. If it
hangs like a basketball star or is slow to return to the idle reading you
should suspect exhaust restriction, which would prevent the engine from
pumping against the pressure.

The only plugged cat I've seen didn't need that kind of diagnosis. The
symptom that preceded the crisis was poor power - not bad at low throttle
settings but the last half of the throttle didn't do any good. The power
problem became worse until it could no longer make it up the hill to get
home. When the air cleaner was removed, gasoline spray was visible in the
carb throat when the throttle was opened. The cat was so plugged that when
we tried to exhale through it there was only a bit of leakage, like a couple
of soda straws. But the engine never ran rough.

Mike

 

On Jan 13, 11:31 pm, foofightersfan7710

It is rather amazing how often someone uses aftermarket parts like you
did only to find they are why the car is now not running well. OEM
ignition parts and oxygen sensors are worth every penny with Hondas.
Do not rule out one or more of these AM parts being the problem or
contributing to it.

Has the timing been checked?

Meanwhile, use the shop manual to purge the cooling system thoroughly,
following the steps verbatim. Air in the system causes some engine
sensors to go whack-o.

 

Hi there,

Just wanted to thank you guys for your help. I found the problem. Runs
good now. Ended up beening a vacuum leak that I had missed before.

Thanx

 

Hi there,

Just wanted to thank you guys for your help. I found the problem. Runs
good now. Ended up beening a vacuum leak that I had missed before.

Thanx

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And thank you for the follow-up. It will help us with the next guy.

Mike