ECM gone BAD? a little suspect! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ITZA72 · 04-17-2004, 12:13 PM

fellow members - my 87 EFI's been in for an overhaul - (spun a bearing but otherwise ran great) however the mechanic just hasn't been able to get her to stay running once put in gear (auto). After nearly two weeks of chasing vac lines, wires etc he believes the ECM went bad? My question - how could this have happened? shorted, pinched or ?? wiring ?? Gone from good to bad while sitting or perhaps they hooked something back up wrong?

Before I get stupid with the shop owner I thought I'd throw this out at at you all. Thoughts . . .?

Bless the troops deployed and supporting our great nation all over the world!

NeCrOmAnCeR · 04-18-2004, 12:20 AM

Has the IAC moter and passage been checked? TPS. Will it idle OK with the A/C on (idle increases like it should to compensate for the compressor load)?

When it dies does it act like it runs out of fuel or does it seem like something stops the engine? Sometimes the TCC solenoid can get stuck open and cause the TC lockup clutch to stay engaged, thus killing the engine when it is put in gear.

Jason Spears · 04-18-2004, 11:42 AM

What causes him to suspect the ECM? Has he gone through all of the proper diagnosis procedures to determine this? (Checking all ECM terminal voltages, examining all the data with a SCAN tool while the engine is running?) A factory service manual (Fuel, Drivability and Emmissions) has all the proper procedures

I've had experiences in the past where mechanics just didn't understand how the fuel injection system worked and could not properly determine what the problem was with my truck.

Good Luck.

04-17-2004, 12:13 PM	#1
ITZA72 Paz Join Date: Jul 2000 Location: Minot, ND Posts: 52	ECM gone BAD? a little suspect! fellow members - my 87 EFI's been in for an overhaul - (spun a bearing but otherwise ran great) however the mechanic just hasn't been able to get her to stay running once put in gear (auto). After nearly two weeks of chasing vac lines, wires etc he believes the ECM went bad? My question - how could this have happened? shorted, pinched or ?? wiring ?? Gone from good to bad while sitting or perhaps they hooked something back up wrong? Before I get stupid with the shop owner I thought I'd throw this out at at you all. Thoughts . . .? Bless the troops deployed and supporting our great nation all over the world! __________________ 1987 GMC SC 4x4 2004 GMC HD 4x4 Dmax'd n Edged Rollin!

04-18-2004, 12:20 AM	#2
NeCrOmAnCeR Registered User Join Date: Feb 2004 Location: Hodgenville, Ky Posts: 735	Has the IAC moter and passage been checked? TPS. Will it idle OK with the A/C on (idle increases like it should to compensate for the compressor load)? When it dies does it act like it runs out of fuel or does it seem like something stops the engine? Sometimes the TCC solenoid can get stuck open and cause the TC lockup clutch to stay engaged, thus killing the engine when it is put in gear. Last edited by NeCrOmAnCeR; 04-18-2004 at 12:25 AM.

04-18-2004, 11:42 AM	#3
Jason Spears Registered User Join Date: Dec 2002 Location: Stoney Creek, ON Posts: 89	What causes him to suspect the ECM? Has he gone through all of the proper diagnosis procedures to determine this? (Checking all ECM terminal voltages, examining all the data with a SCAN tool while the engine is running?) A factory service manual (Fuel, Drivability and Emmissions) has all the proper procedures I've had experiences in the past where mechanics just didn't understand how the fuel injection system worked and could not properly determine what the problem was with my truck. Good Luck.



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.