Join Date: Mar 2017
Location: Egg Harbor city, NJ
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1997 GMC C8500 w/3116 CAT
I have a 3116 Cat with a 40 pin ECM that will not start. I know it is very rare for a 3116 to have a ECM, and at first I even thought it was a 3126. But it is a 3116 serial #8WL02985 which you can comfirm with your Cat dealer was ship with Electronic Injection.
Now for my Problem. Pulled onto the job one day with load of hot asphalt. Noticed truck running like crap although ran fine there. Managed to keep running long enough to unload. Brought back to shop on tag trailer. Truck would start but would not idle or stay running. Pulled primary fuel filter and sure enough, half full of nasty looking water. Checked filter on motor, looked ok, and replaced both. Primed system, turned key. Worst than before. Check fuel pressure, None. Replaced fuel pressure regulator on back of head. Got fuel pressure, still will not run. Load back on tag trailer take to local shop. Local shop say injectors only getting 9volts, ECM bad. Find used ECM and send to Cat with mine to have Programmed. Pulled, cleaned and painted motor and frame because of rust while ECM was out. Put all back together.
After I put engine back in, it would not crank over. I noticed the shifter display for Allison tranny was not lighting up which would cause neutral safety switch to keep starter from cranking. Bypassed ignition and motor cranked. Found power supply to trans and bypassed. Cranks over now, and still won't start. Getting power to pins 6 and 28 on ECM plug. Getting no smoke from exhaust why cranking which tells I'm getting no fuel, which makes me think injectors are not firing. Still don't understand why I lost power to trans because it was working fine before pulling Engine. Took picture of all battery connections before disconnecting and cleaned all connection and new grounds. Part numbers on ECM's match, but could one ECM be for standard trans while other for automatic?
If I'm getting power to pins 6 and 28, and grounds to pins 4 and 5. Which I am. She should fire off. I got no codes that would indicate a bad HUEY pump. But this no power to Trans is a mystery, and check engine light does not come on when I turn ignition switch on. But everything else seems to work fine.
Any help would be appreciated.