To follow up on this thread, but slightly different thoughts...

https://www.thirdgen.org/forums/dfi-...home-mode.html

I have a '90 IROC, L98 mostly stock (except the turbos) 6-speed, '7730, running $58 (poor tune, but it ran well enough) and 47lb/hr injectors (upped FP on 42's). Was originally an LB9 5-speed car, so limp-home mode is for that combo.

It goes in and out of limp-home mode but mostly stays in limp-home (and barely runs of course), I'm sure of it. What else could it be when I fully remove the EEPROM while still running and nothing at all changes?

Anyway, I've ruled out the ECU... Bought a reman'd parts store '730, then an original '92 Firebird V6 '730 from a JY (they tested it) just to be sure, I've swapped EEPROMS, tried the old $8D code (and MAP sensor) I had tuned well before the turbo install, back to the $58, and the problem doesn't change.

So, what mechanically might cause the ECU to freak out and go into limp-home mode? When I first start it, occasionally it will run perfect without any SES for a short time. I datalogged briefly before the datastream froze upon jumping back into limp-home, everything appeared fine when it was running fine.

Might be coincidence or a direct cause, but the same day this came about my heater core sprang a leak. None of the new ECU stuff is wet or touched by coolant at all.

I'm at a loss.

 

You are running some crazy stuff, I have no idea whats going on in your case. I do know that with my '87 MAF car, it was the 33 error code that would put the ECM into "limp home mode". Are you throwing an error code?

 

Are you using a ZIF? My ZIF was not soldered in place(sat in original socket) and gave me intermittant contact and flipped into limp too often.