Can anyone tell me if a bad ECT can affect the idle speed? This is on an 89 Accord with the A20A3. Thanks.

 

it did on my h22 I fixed it cleared out the code on my s300 and it idled fine so its possible.

 

Ok thanks. The CEL came on and it started idling at 1500 RPMs and the only code it threw was bad ECT, so hopefully a new one will sort it out.

 

You do know there are three (3) "ECT"

ECT switch - controls rad fan.
ECT sensor - supplies ECU/ECM with engine temp.
ECT sending unit - for the temp gauge in cluster.

The ECT sensor if bad would allow engine to run rich. 94

 

Couldn't of said it better myself.

 

Well I replaced the ECT sensor and cleared the code, all went well, it idles right at 1000RPMs now as opposed to 1500, but now it bucks for a bit under light acceleration for about 20 seconds and the proceeds to run fine until I stop at a stoplight. While leaving the stoplight it bucks again almost like it is misfiring but it has not triggered the CEL. Any suggestions?

 

If you think it has a misfire it's got to be one of the following

1. Spark
2. Injection
3. Compression

Those three variables have their own specific tests in order to find out what is wrong with the car when there is a 'misfire.'

Did you use a brand new ECT or a used one ?

 

Brand new ECT, however I suspect that the timing belt has jumped because at higher RPMs it runs fine, it just "misses" from idle to around 3500 RPMs, after that it runs like a champ

 

Joke was on me, cylinder 4 fouled a plug, all is good now

 

Fixed the plug, didnt fix the problem, I think I'll give up

 

what was the compression in that cylinder?

 

I havent checked the compression yet due to weather, however what are the chances its a TPS going bad?

 

Usually your car will prevent itself from accelerating and picking up any type of load(stalling) if a bad TPS is present, and most likely it will throw a code.

But then again I've seen many escape the illuminated CEL light(dtc code) where it will be a bad TPS sensor, but no signs of a CEL.

Only way to test a potentiometer like that is to put a multimeter to it, and measure voltage at closed throttle and WOT throttle. Now when your doing this, you also have to note down the increase in voltage by steps, there can't be any disturbance in such a test or voltage variation. The numbers have to progress gradually as you progress at the same rate with the throttle blade.