Join Date: Nov 2012
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SOME PROGRESS BUT not solved
Ok this morning truck had sat over night outside and temp is 28 degrees F . I connected a 12 volt test lamp between negative the battery post and the load side large terminal going to the glow plugs on the GPR , turned key to on and lamp did not light up, showing no voltage to glow plugs . So I repeated this test but this time I added a jumper wire from negative battery post to the small terminal on the GPR with the orange/violet wire to the PCM , turned the key on and the lamp lighted brightly showing voltage to the glow plugs . I kept the key on for 10 seconds after the WAIT TO START went off and then turned the key to start and it fired up immediately and ran great .
So now I know how I can get my truck to start when cold and not plugged in , but I still Don't know where the problem is ,the PCM , a sensor , or bad wire ?
After truck was warmed I shut it down and put the test lamp and jumper wire back on the same as described above . turned the key on and the lamp lighted for less than 1 second and turned off , I cycled the key a few more times and the test lamp did not light at all unless I waited 2 or 3 minutes before turning key on and then it would light for short blink .
So I think some temperature info must be getting to the PCM , because the GPR is disengaging the voltage to the glow plugs on the warm engine even with the ground jumper still connected .
Anyone know where the problem is ?