[7.3farmer478]

Hauling a load of straw and the truck died

2001 f350 won't start. No wts no tach no oil pressure no blown fuses

New idm,cps uvch,glow plugs gpr ipr

Truck will run when the idm is not bolted to the truck. But as soon as its ground it dies.

Is it the pcm or something else.

 

[RT]

How did you come up with your parts list? No WTS points to the PCM not getting power on all inputs. The most common cause is a shorted fuel heater with a subsequent blown fuse #30. Did you check that?


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[7.3farmer478]

Yes I checked the fuel heater.
And all fuses and relays.
Parts were replaced cause I was not getting any Fire tru the gpr until the idm was unbolted. I have checked all the other stuff people say to check. No bare wires no blown fuses.

 

[RT]

Do you have a friend with a 7.3 that you can test the PCM with?


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[7.3farmer478]

No I don't have anyone close by with one. I hate to buy a new ECM and it don't fix the problem. Came here to see if anyone else has has this problem

 

[bugman]

It doesn't make any sense that the truck will run with the IDM unbolted from the fender.

When it is unbolted do you get the WTS light and does the truck start on it's own?

You might also try swapping relays around. The PCM relay with the blower relay and try it and then swap the IDM relay around.

Here is a diagram of the under hood fuse and relays

 

[7.3farmer478]

I know that's what's so odd that it will only run with the idm unbolted. And yes I get the wts light when unbolted.

 

[bugman]

I think that I would start checking grounds. They will do strange things when one is missing or is corroded enough that it isn't making a good contact and this sounds like a weird type of problem.

Try bolting the IDM up and then take a jumper cable from the negative on the battery directly to the IDM and see what happens.

 

[7.3farmer478]

I've checked all the grounds. Unplugged all sensors and cleaned connections. Nothing I try works

 

[RT]

Where are you at? Someone might be close by and willing to try to test their PCM in your truck.

 

[7.3farmer478]

Took the ECM out of a friends truck. Did not fix the problem.

 

[RT]

I would suggest checking all the positive feeds to the PCM and IDM next. I suspect one isn't getting good power. Test them plugged in- sometimes with a bad contact you'll get 12 volts unloaded and it will drop to zero the second a load is placed. Grounds are that way too. A loading meter helps here.


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