Hi Turbo forum,

Not getting any action from the large 924-968 forum. Are people in the turbo forum (I usually just read and post here!) more technical and better at troubleshooting?

Here is a link to the thread

https://rennlist.com/forums/924-931-...s-already.html

Here is the original post (no replies) below if you'd rather post here. I really need to nail this down. Car is at the shop so I will relay anything I find here to them.

"Hi RL. It's time. My car is at the shop, and we have not made much progress into a 'running rich all the time' condition. I've search, plucked ideas, tried them, and no change.

89 944 Turbo. The car came with an Autothority Stage 2 kit (chips, jetted banjo bolt). Ran rich. Removed and put back OEM chips and banjo. Still ran rich. Rich being 22mpg no matter how it was driven.

Put in an A-Tune. Now getting 20mpg, super rich at start-up (3 cylinder). Added 3-bar FPR as per A-Tune requirements. The following has been done to try and troubleshoot

Fuel pressure - Have a gauge on it, looks good, holds pressure
FPR or dampener - FPR was a new 3.0bar Bosche, now it's a 2.5, still rich. Dampener not checked.
Injectors - Not leaking, original
AFM - Not checked beyond visual/vacuum
Coolant temp - Replaced the DME Temp sensor, wiring seemed fine
FQS switch - set to 0
O2 sensor - Is this looked at during a cold start? We can wire the 0-1V output from the Wideband to the DME, but have not done t his yet
Vacuum/boost leaks - Nothing significant found with smoke machine. Low vacuum during startup, but car has a street cam so this I am told is to blame (~8psi, warms up to ~14psi)
Weak ignition system (can cause false WBO2 readings due to misfire /incomplete burn) - New spark plugs, not too many miles on the other stuff but can look into...
DME chip (although unlikely, it is possible to get a bad burn) - Maybe, but the car also ran rich with the original OEM chip
Grounds - Grounds look good according to experienced tech looking the car over.

I just don't know where to look now. We're talking <10.1 at start up, and it gets into the 11s (maybe a hair higher but did not discuss/has yet to be tested) on driving.

What would be telling the car to run rich, all the time?
"

 

Out of spec or damaged AFM? Check voltage on DME #7 at idle with warm engine. Report back RPM & voltage value.

Verify TPS at DME. Should read IDLE at idle and WOT at wot.

Injectors out of spec? One or many supplying more fuel than normal.. Read spark plugs for a color difference.

 

Yeah, start with the basics... check the plugs, verify the calibration of the wide band, verify that the stock O2 sensor is working.

Use accurate air/fuel ratios to make decisions - not MPG.

 

John has covered the usual suspects.

One trick I use is to check header temp. You may have a stuck or clogged injector that is overloading the others

 

I will pass the info along as more things to check. Thank you guys. Additional info welcome if something comes to mind. TPS is new as of 2010 (done by PO, some other shop). Will consider all others. Thank you again. Will post with more info.