Chevy/GMC 6.2L and 6.5L Discussion of Chevy and GMC Trucks with 6.2L and 6.5L Diesel Engines

1993 6.2 Diesel ECM

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Old Dec 29, 2014 | 06:11 PM
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Default 1993 6.2 Diesel ECM

What does this govern? My trucks glow plugs used to flicker when driving before I had them manually overrode from the ECM.

My truck is a 1993 K1500 J CODE Swapped intake(originally C code(egr)), 5 speed manual NV4500, 4X4

When I kill my glow plugs from the ECM my truck idles lower. I also noticed random jumps in power.. and sometimes I notice gutless lagging speed.

Thanks for input
 

Last edited by Finn92; Dec 29, 2014 at 06:17 PM.
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Old Dec 30, 2014 | 06:32 PM
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So I figured I may have a faulty lift pump.... when I turn the key I can only hear it for a couple seconds then quiet.This might explain the jumps in power and low idle speeds... Any input from anyone? Or would my ECM control my lift pump?!(doubtful)
 
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Old Jan 2, 2015 | 08:39 AM
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with a 93 the ECM usually only controls the auto trans.
if you havea standard then I have no good ides what the ECM does?

I suspect that you may have a faulty oil pressure switch if the LPdoes not operate when the engine is running.
If you have a prime cycle on the LP circuit then it may have been modded to run with the glow relay?
 
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Old Jan 11, 2015 | 02:12 PM
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GM 6.5L V8 Turbo Diesel EngineStudent Handbook
344 pages of AWESOMENESS! lots of pics and illustrations too..
Although not intended to replace FSM, it is far more accurate and useful than any Haynes, Chilton, or thers worthless 6.5 publications.

Suggest you down load it...
 
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Old Jan 11, 2015 | 02:15 PM
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Check the fuel heater. It can malfunction and cause the WTS and WIF lamps to flicker on its way out, eventually it could pop the ECM fuse disabling the glow plug system and lift pump circuit..
 
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Old Jan 12, 2015 | 04:06 PM
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hmmm I just hooked up the fuel pump relay to my battery and can hear it clicking away. But i dont hear it clicking at start up.
 
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Old Jan 12, 2015 | 06:30 PM
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Originally Posted by Finn92
How do I go about checking my fuel heater. I just hard wired my fuel pump fuse to my battery and could hear it clicking. So I guess my fuel pump isnt shot?

Thanks for your help
See attached.. You could simply unplug it, replace the ECMB fuse and see if everything returns back to normal. If so, you know the fuel heater is defective and wont need to remove and disassemble the FFM to properly "test."
If you find the fuel heater defective,, plan to replace it. FWIW a new fuel heater alone cost nearly as much as a new completely preassembled "drop in" fuel filter manager..
 
Attached Thumbnails 1993 6.2 Diesel ECM-fuel-heater-functional-check-pg1.jpg   1993 6.2 Diesel ECM-fuel-heater-functional-check-pg2.jpg  
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Old Jan 12, 2015 | 07:40 PM
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The lift pump relay only works during cranking,the OPS powers the LP while the engine runs.
 
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Old Jan 13, 2015 | 10:51 AM
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Well I pulled my fuel heater plug and it ws completely corroded and basically broke off at the prongs. I think that is the issue.... Should I replace with a 6.5 fuel filter system? Can I run the truck without one?
I really appreciate your guys help.
 
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Old Jan 13, 2015 | 12:11 PM
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Go ahead and run without it-does very little really.

Just be sure to use adequate amount of fuel conditioner for antigell.
 
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