Hi all,

I have a '92 Accord that is suffering from a rough idle and overheating. Part of the overheating is due to low coolant and improperly flushed system (sat for 8 yrs, drained coolant prior) but these issues were present before it sat. When first cranked and it begins heating up, it has an idling issue where it'll rev up to around 2k, then drop, then rev, then drop, over and over again. I also noticed that when it gets up into the almost red (before I shut it off, of course) the electric fans don't kick on at all. I'm thinking there may be a sensor that isn't sending the computer the right info that may be screwing it all up, which results in improper temp readings. The computer is calling for more fuel being dumped into the engine to warm it up although it is warm, and the fans don't kick on because the computer doesn't see a need for them to. Thoughts?

 

Your fans should be a thermal switch no computer involved. Sensor closed due to temp turning the fan on. Test your fans with direct battery power. However one is for they ac condenser. The reving will take some troubleshooting. A list of things. Start with the easy like fuel pressure, tps voltage. Timing and vacuum leaks

 

I had that strange idling problem too. What helped was when it revved like that, I put my foot under the throttle pedal and lifted it up as hard as I could. Maybe your throttle cable is a little sticky.

 

I have a 91 Honda Accord EX that used to do the same thing as yours . Your idle issue with the hi/lo revving is most likely due to your IAC valve. I deleted mine on my '91 accord ex. There are some sort videos on you tube that will show you how to do the same. Ever since i removed the iacv my jobs no longer 'lopes' when idling. All you need to do the delete is a metal plate done rtv sealant and a hose coupling, as well as a basic socket set.