Car starts but won't run with Turner/TMS chip

[grib]

Unfortunately I am having a problem with a chip I bought from Turner Motorsports. The car starts with the chip in, but then barely runs and dies after only 10 seconds. I can keep it from dying by keeping the throttle at 1500-2000 RPMS - but it will die immediately after if I let off the throttle. This doesn't appear to take long enough to trigger the CEL, so there isn't a fault code from the ECU.

The "stock" chip starts and runs decently, but the CEL will come on after 5 minutes or so (probably due to the injectors being unmapped, but I have not read the code).

S52 w/OBD-1 conversion
Red label 413 ECU (tried two different units)
THR wiring harness
24 lb injectors
UUC flywheel
Tried both 3" and 3.5" MAF
Tried two different TPS

I also tried with combinations of the TPS and MAF unplugged but it ran even worse that way. Most of the sensors on the car (knock, crank/cam position). The ignition coils are new as well.

I sent the chip back to TMS, and they returned it saying that they tested it and did not find a problem.

Has anyone else ever had this problem?

[matt]

How is your ICV?

[grib]

Have not tested it. It's used, but I cleaned it prior to installing. It does hum quite loudly when the key is turned to on.

Is there a procedure to test?

[erik325i]

The "stock" chip starts and runs decently, but the CEL will come on after 5 minutes or so (probably due to the injectors being unmapped, but I have not read the code).

I have the Peake Research code checker tool if you want to borrow it. I'll bring it to the meet on Sunday.

-Erik

[matt]

You may have another running issue with the motor that isn't chip related.

It really sounds like a MAF issue. Could be ICV also.

[BeirBrennerE30]

ICV or a major vac leak...

my biggest probelm on my first 2 swaps were vac leak related and the car would start idle rough and sputter out but on throttle be better. sounds like what you have

[Beej '86 325es]

The bentley has a relatively simple way to test the ICV, that just takes a 12V power source and a couple of wires.

[grib]

I have the Peake Research code checker tool if you want to borrow it. I'll bring it to the meet on Sunday.

-Erik

Thanks Erik, I'll take you up on that.

Matt, I have ordered a new MAF to see if that's it. It's something I wanted to get anyway. I am also going to replace the O2 sensor this weekend.

[matt]

It's not the O2 sensor.

[1990m3]

vacuum leak sounds likely. There aren't too many vacuum hoses on these engines, check your connections again!

[RyanZ06]

I dont think it's a vacuum leak. I am having a similar problem, I have SEALED all vacuum ports except for those vital few (FPR, brake booster). My car has identical symptoms.

[trent]

Are you sure you guys didn't miss the vacuum port on the TB?

[grib]

Are you sure you guys didn't miss the vacuum port on the TB?

I capped off the two coolant ports, but there is one left. This is probably the vacuum port. Is this supposed to connect to the purge valve?

[trent]

Yes, that is a vacuum port. I don't know if this to your problem but it certainly is an issue. It is supposed to goto the purge valve.

[BeirBrennerE30]

on obd1 engines there is another vac port on the icv pipe that like everyone forgets. Also the throttke body purge port that trent mentioned... jb weld is your friend