Fast Idle...

[MaaseyRacer]

Ok i just finished my mpfi swap the other day, and at first i did not have a fast idle, but now when i start the car, the engine revs to like 2000rpm for a few minutes, and then drops the revs to under 1000rpm. I was wondering what could cause this??? I am going to replace the PCV valve today, because when i pinched it, it did not rattle, and that is what my helms books said was the check for that. Would a bad PCV vavle do this to my car??? Also I am not throwing any codes and the car is an 89 civic DX.

 

[gupta_p]

Yes .. please do explain more about this PCV valve stuff. I'm VERRYY eager to hear what it's meaning is.

 

[solblu]

What map sensor are you using? Did you swap the two wires on the plug? Does the idle lope?

 

[asmallsol]

Originally posted by gupta_p@Mar 23 2003, 02:32 PM
Yes .. please do explain more about this PCV valve stuff. I'm VERRYY eager to hear what it's meaning is.

PCV = Positive Crankcase Ventalation Valve, the first ever emissions device. What it does is it puts the blow by gases back into the intake manifold instead of it excapeing into the atmosphere.


Yea it will cause this. On my freinds saturn, we remove to check it, then he forgot to put it back in, he started it and it idled at arond 2.5k. Also when you remove it, if you shake it and it rattles, then it is good, if not, it is bad.

 

[90 accord]

i thought that was just the car trying to get up to operating temperatures quickly, so all of the clearences are propper.

 

[tdehnel]

Yeah, 90accord is right on this one. It's just warming everything up so you're not driving around with a cold engine.

 

[asmallsol]

oh, i just read the first post real fast. Did not read the part where it went back down to 1000 rpm. That idle is still a little fast but nothing really to worry about. Was it colder out that day (40's or less)