suppakoopa
New Member
First off, I'd like to say this site has helped me out tremendously throughout my latest 6.5TD adventure. Tons of great info and very informative people, so much so I have always been able to find what I'm looking for up until this point, without having to ask for help. I have a 1995 GMC Suburban K1500 with a 6.5TD vin F that I got cheap from a guy on the list. Vehicle was not running nor did it have ant batteries in it at the time of purchase, so I couldn't even crank it. What drew me to it was the Greasecar WVO kit that he had them install in it a few years prior to this. More on that later, if anyone wants to hear about it! Anyway, he told me it died on him while running on WVO and he couldn't get it restarted. His mechanic said it most likely needs a new IP and injectors and the turbo was seized. The mechanic had taken the turbo apart and left all the pieces scattered across the engine bay, the compressor wheel would not turn freely. So I got it home to start some diag on it, after putting batteries in her, gave it a crank and all I hear is screeching. The clown had destroyed the teeth on the flexplate and the pinon gear on the starter motor in a attempt to restart it after it died. Engine would not turn over. I manually turned it over to make sure it was not seized, and it was not. I then decided to pull the engine for flexplate replacement and to look at the sludge i was fearing to find in the oil pan that may have killed the turbo. Skip ahead to new 40 over pistons, complete bearing and gasket set, valve seals, rebuilt injectors, new crank sensor, used IP from Ebay off a running truck and a through cleaning of every god forsaken part in and around the engine to where I am now. I have fuel to the IP with good pressure from the new lift pump, with the OPS mod,(also added a toggle switch to run the lift pump prior to cranking) and plenty of fuel out of the return side of the pump, but none to the injectors. I removed the fuel shut off solenoid and verified its proper operation by energizing it out of the pump with the key. I have cranked this thing silly and nothing. I know my PMD is good because I have a 96 K2500 suburban with the same engine that will run with that PMD. So before I condemn the used IP I installed I started looking in to the wires that feed the IP to see if the PCM is sending the inject signal. Buddy has a very good write up and diagram that i used to troubleshoot this circuit. At the PMD wiring harness pin E I'm getting 5.3V while cranking, in specs. PMD pin B is 1.097 VAC, in specs. I have .3 ohms between terminals B and F in the PMD harness which is the the wires off the back of the IP. The rest of the wires in the harness D is B+ and C and F are both grounds. What I think is the problem is PMD pin A that is only putting out .3V and should be 1.2V while cranking. This is the fuel inject control wire that I traced back to the PCM and shows the same .3V out of PCM pin BC14/BD13. The weird thing is after I stop cranking the voltage goes to 4.9V then drops back to 0 after a couple of seconds. Not sure if that is normal or not?! So before I replace the PCM, which may have been the problem all along, I'm wondering what does the PCM need to see in order to send the proper voltage to the PMD to start this beast? I'm tempted to put some sort of voltage resistor with 1.2v into pin A and see if I get any fuel! I have tried disconnecting the optical sensor while cranking and nothing. Disconnected the new crank sensor and nothing. All of my grounds and battery contacts are clean, i have triple checked that. All fuses everywhere are good. I have the SES and glow plug lamp on the dash. Any advice or imput to get me outta this mess might get me back into bed with the wife! Sorry so long but I thought a little history might help.
