Got this problem I have been working on for a while with the idle on my hatch. Problem is that the fast idle doesn't work very well, if at all. When the car is finally "up to temp" it still idles around 1,500rpms. Usuaully, but not always, it also fluctuates about 500rpms up/down, up/down when idling. I am running a chipped P28 with the Mugen program. When using a stock P61 (not chipped) the problem still persists, but its not as bad. I recently noticed my intake had stopped making the sucking sound when the engine was shut off. After checking a few options I found the idle screw was too tight and this was the reason the sound was gone. As odd as this sounded, I correctly set my idle to 600rpms with the IACV disconnected and then plugged it back in. The idle still sat at 1,200rpms. Today I was out there messing around some more to try to find my issue and when I unplugged the IACV I found no change in RPM. The car was completely warmed up and this was using the P28. There is 12v on the yellow/black wire as there should be. This is the second IACV I have used with the same results. I did try cleaning the IACV by shooting carb cleaner into the intake port on it while the engine was running. When I plugged the IACV back in there was a "pop" and the RPM increased and began fluctuating only 100rpms or so. There was also a slight pop in the exhaust. I tried setting the idle to 600rpms with the IACV disconnected, but the car died. The screw was also almost completely closed and again I lost the sucking sound from the intake. Also, the car is failing smog test as the HC are too high. CO seems fine. I don't know if this problem is related to the smog or not, just thought it might be nice to include. Anyone have any ideas? The IACV I am currently using is off a D16Z6 that was working correctly. The engine currently in the car is a B17 with a fresh rebuild. Yes, the car runs an 8.5lb flywheel but I am 99% sure this is not my issue. The car will periodically correct the problem and idle perfectly... Problem is this is a very rare occurance and I can't find out what causes it.


Modified by Hybrid93Eg at 4:57 AM 5/2/2003

 

Vacuum leak somewhere?

and yes I have no idea

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RangerDan &raquo;</TD></TR><TR><TD CLASS="quote">Vacuum leak somewhere?

and yes I have no idea</TD></TR></TABLE>

I have tried spraying carb cleaner all around the intake, throttle body, injectors, hoses, etc.. No change in idle. I have looked prolly 1,000 times for a vac leak and come up with nothing. Vac gauge on the engine shows 22 at idle.

 

the sucking comes from air filing up the "vaccuum" inside the intake manifold and leaking past the throttle (body) plate. i think your tb is adjusted open too much ( air fills vaccuum fast and wont make "sucking" noise) and it sounds like the adjustment screw is loose. put a dab of loctite on it.