I'll try to keep this as concise as possible for those of you who don't like to read much.

First of all the mods:

2.0, S3 cams, ported Skunk2 IM + TB, 2150cc FIC, double fuel pump, 6466 FF, Sparktech CDI, and some other stuff that I can't think of right now.

The issue:

Can't get my car to idle properly. This is a new build.

Target RPM without fans = 1100~
Target RPM with fans = 1250~

I'm getting the exact opposite of that.. When the fans kick on, the RPMs will drop to 1100~ and when they shut off the RPMs go up to 1300.

AFR without fans = 16 - 18
AFR with fans = 13 - 15

I did the SAS thing on Evoscan. TPS is at 14.1% but that still doesn't seem to fix the problem.

I have 3 fans, 2 for my half radiator, one for my oil cooler. I believe they're all SPAL fans and they're all relayed.

I did several boost leak tests with flying colors. Fuel pressure without vacuum line is around 43psi. I switched the IAC but that did absolutely nothing. There's no RPM jumping, but the AFRs fluctuate a lot.

Someone help me with this, please. I'm just fed up with it. I can't find the solution for the life of me.

 

You need to measure the pressure with the vacuum line connected.

Setting it with the vac off is OK but when it's idling , the vac line is connected.
The spec is 33 PSI.

But there will be more than just one thing wrong.
Like the cams not degreed properly

 

Bump. Help your fellow Evolutian.

 

Sounds like no additional air is allowed to enter your intake manifold when fans are on. The drop is probably from alternator load to run the fans.
Did you check your IAC?

I've always wondered how accurate UEGOs are when they read over 14.7 AFR.

 

I did check my IAC. I replaced it with a working one on my friends car just to see if it was the culprit but no change.

I can check tomorrow and try a third IAC just to make sure, but I doubt it'll change anything.

When the fans are on my AFR and RPM are perfect. 14-15 AFR and 1200~ RPM. The issue rises when the fans turn off. My RPM will go to 1400 and my AFR will drop to 16-17, which shouldn't happen since the target RPM on the tune is 1100~... My tuner is a highly respectable tuner in the U.S, so I'm not even going to think that this is a tuning issue.

 

Try testing with IAC off and see if idle and AFR changes.

 

So here is something new.

I saw a thread about how a proper IAC should work, and here is the clip associated with the thread:


I don't know anything about how a properly functioning IAC should work, so I took it is a fact.

I had 3 IACs at my disposal. None of them had the same effect as the IAC in the clip I posted above. All of them would click out once and stop.

I didn't know if this was an electrical problem or was it the solenoids that were bad, so I took the 3 IACs to another Evo that was working and idling well and plugged all 3 IACs to the Evo. None of them worked the way the IAC did in the clip. In fact, none of them worked at all. Not a single click.

I took them back to my car, and they would click once only.

What does this mean? Is the clip misleading? Are all 3 solenoids fried?