1988 Honda Accord re: Irregular and High RPM engine idling

PEAKNSEA

MEMBER
1988 HONDA ACCORD
4 CYL
2WD
AUTOMATIC
18,600 MILES

When engine is first started (cold) the engine idle is way high. If you drive at all, soon it will return to normal or close idle. If you place in neutral immediately after first starting and running for very short time, it starts to surge idle (slow to fast idle surges) and will continue until you just drive the car a few minutes and engine fully heats up. Based on your answers to similar problems, should I be looking at IAC, PCV valve or neither of these?

Thanks,

J.S.

1 Reply

KHLOW2008

MECHANIC
41,814 POSTS

Hi J.S,

During cold start, the idling rpm should be high, but not extremely high and gradually reduces as the IAC warms up and begins readjusting the air flow into the intake manifold.

When more air than required is going through the intake manifold, it would result in too high an idling speed and that is when surging occurs as the engine computer tries to compensate.

You are correct about checking the IAC and PCV and on top of that, there are a few more items that you should check.
1. Idle adjust screw. If it has worked itself loose, the idling speed would be too high.
2. Coolant level. Check if there are any shortage of coolant in the radiator. If level is ok, you need to check the IAC coolant hoses, both should be hot after engine has warmed up. If any is not as hot, the circuit is clogged.
3. Vacumn leakages. Check for dislodged or broken vacumn hoses.