02 Peterbilt 379 won't start.

Cam poison sensor or fuel pressure regulator. Is only other things I cam wrap mind brain with.

 

Thing is it ran great till the battery change, also won't communicate. As a good rule if it was fine and was worked on them not fine that's the place to go. I will agree that cam sensors will fail without warning or code, but it would still communicate. Same as if fuel pump had an event.

 

I'm no ASE tech, but when I read this I question a few things that may seem irrelevant... You say pin 70 of ecm has power, but are you also checking using the ground within that clip, or body chassis ground? Does your check engine light; light when you first turn on the ignition switch (meaning there is power to the ecm)? I wonder if one of the batteries was ever bad or just a symptom.

 

Test light is connected direct to battery ground. Also I can't remember the PIN numbers but there where 3 with direct ground when tested from battery positive. Also there are two pins that are constant battery positive when checked to battery ground. I'm thinking it will be going back down the road to the dealer, I don't have time tomorrow to play with it. Just out of curiousity, is there any other fuse, relays that might be connected to this besides the one fuse by the batteries, and the fuse box beside the clutch pedal?

 

there should be a key one fuse

 

key on fuse

 

three hots with key on

 

Simple question.

When you turn the key on do your check and stop engine lights light up?? They should light up for 2-3 sec then go out. If they don't then who ever installed your battery's probley hooked up the wrong cabels and fried your ecm.

 

The stop engine light and check engine light up and turn off within 2-3 seconds of key on. I'm unable to know what fuse and relay is what in the box because the darn cover with the label is missing. However I have checked all fuses with a test light and replaced all the relays with new ones I had laying around in the shop.

 

If your check and stop lights are doing there thing then I'd look at the fuel side.