Help me get my car to idle good (Fiero swap)

[fieromadman]

Ok, so here's the deal, a while back I made this post over on realfierotech:

I have had on going idle/driveability issues with my car ever since I got the cams/96-97 intake manifolds put in it. Mainly the driveability is good, but the idle sucks ass. In fact, it seems that whenever it is below 2000 rpms and you aren't on the gas at all it runs like shit. 4th gear at 30 coasting you may as well forget about. Idling at stop lights, ditto, unless you are bliping the gas occasionally.
I know that it is not the cams that are doing it because someone else has the same cams in their car and it runs and idles fine. Although it has not been professionally tuned, neither was that guy's.
All the sensors seem to be reading correctly, and since the engine has had the cams and intake manifolds on it has been gone over throughly, and the intake manifold gaskets were replaced (and torqued in the correct pattern to the correct specs), so I think that it is safe to assume that there are no gasket leaks causing the issue. There has also been a new chip burned during that time to give at least a base line tune on the cams. It made no difference.
The biggest thing that I want to try is doing a vaccume test and a fuel pressure test as well as testing the wires on the TPS sensor for resistance because when I did the intake swap I had to change them. Everything else has stayed the same on the engine so I dont see any other wiring problems taking place because it has been like this since day one when I got the engine in with these cams and intake manifolds on.

Since that post, I re-timed the engine and it is DEAD ON. It was a little off, and by changing the timing it made a little bit of a difference. The idle didnt really change but the powerband did, and the engine overall is a little smoother. I've unplugged the TPS and it still idles like garbage. I also cleaned the MAF. The wiring harness was went over and is good. One interesting thing that I noticed was two times ago when I took the engine out the cam position sensor was loose and after some research on this forum I think that the cam position sensor could be the culprit! Another thing that I was thinking was that it could the CASE learn that needs to be done but I'm not entirely sure if that can be done with the 94-95 ECU.

Here is a post that seems like he has the same problem that I do:

http://www.60degreev6.com/showthread.php?t=35561&highlight=stalling

To be continued...

[fieromadman]

Well no suggestions?

[Emc209i]

Jeff, if you think it's the cam sensor why not data log it.... Find out if you're getting a pulse or not. You may also sift out some other problem when doing so. I'd go over the motor with a comb looking for a vacuum leak; but it sounds like you've already done that. That's the only thing I can tell you without being there to help you find the problem.

[fieromadman]

I HAVE data logged it, but not with a really nice scan tool. Still though, everything that that scan tool showed was looking good except the fuel trim was all over the place, but so were the RPM's.

I have a spare cam position sensor, I'm going to try it and i'll report back what happens. I doubt it will fix anything though.

[Emc209i]

Some scan tools allow you to see cam pulse or cam signal. That might prove useful.

[fieromadman]

Changed out the cam sensor, cleaned the IAC, Messed around with some more things. Figured out that if I unplug the IAC when the RPM's are higher it idles just fine (High, but fine). Figured out that when I unplug the TPS, the car idles fine, again high, but fine, revs fine and everything. Heres a video:



and heres another thread on a different forum with people's ideas of what could be wrong. I go into more detail on this forum with what it does, what I've tried and ETC: http://realfierotech.com/phpBB/viewt...er=asc&start=0