Diesel losing Power

GMC Smiley · 02-14-2007, 06:24 PM

I have a 95 GMC 6.5 Diesel, runs great except for it loses power under load, it probaply goes to half power and I get a check engine light.
If I turn off the ignition and re-start it goes back to normal and the light goes out. It will do it again but only under strong power demands, like pulling a trailer. It is 8600 GVW, 2WD, Auto, fully loaded. It wont keep a code. Can anyone help?? Thanks Bunch!! Ted Cleveland Ohio

bradrhale · 02-15-2007, 09:24 AM

take a code reader with you next time. might be something wrong with the injectors. who knows. see if you cant find a code reader that will read pending codes. that might shed some light.

Russ Weaver · 02-15-2007, 06:15 PM

Sounds to me like its going into "limp home" mode. It might be as simple as a faulty sensor or too high EGT (which can be an injector problem, resticted exhaust, air sensor faulty, etc) The engine is shutting down to protect itself. You'd be well advised to take along an OBD reader, as brad suggested or have the dealer look at it. (or mech of your choice) I think on the older models you need to have the same error 3-4 times before it records it as an error... You didn't mention any mods done, but some of the electronic chips can cause that too. The better ones can bring up and cancel error codes too.

02-14-2007, 06:24 PM	#1
GMC Smiley Full Member Join Date: Feb 2007 Location: Cleveland Ohio Posts: 17	Diesel losing Power I have a 95 GMC 6.5 Diesel, runs great except for it loses power under load, it probaply goes to half power and I get a check engine light. If I turn off the ignition and re-start it goes back to normal and the light goes out. It will do it again but only under strong power demands, like pulling a trailer. It is 8600 GVW, 2WD, Auto, fully loaded. It wont keep a code. Can anyone help?? Thanks Bunch!! Ted Cleveland Ohio

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02-15-2007, 09:24 AM	#2
bradrhale Moderator Join Date: Apr 2006 Location: Texas Posts: 3,609	take a code reader with you next time. might be something wrong with the injectors. who knows. see if you cant find a code reader that will read pending codes. that might shed some light.

02-15-2007, 06:15 PM	#3
Russ Weaver Full Member Join Date: Nov 2006 Location: Burnaby,BC Posts: 20	Sounds to me like its going into "limp home" mode. It might be as simple as a faulty sensor or too high EGT (which can be an injector problem, resticted exhaust, air sensor faulty, etc) The engine is shutting down to protect itself. You'd be well advised to take along an OBD reader, as brad suggested or have the dealer look at it. (or mech of your choice) I think on the older models you need to have the same error 3-4 times before it records it as an error... You didn't mention any mods done, but some of the electronic chips can cause that too. The better ones can bring up and cancel error codes too.