96 F250

[coalroller143]

i have a 96 ford f250, and its has 196,xxx on it. the glow plugs were done in 02 do you think they need changin?

[coalroller143]

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[351fifty]

does it smoke on start up? if you feel like it isnt warm enough then change them, otherwise no

[351fifty]

[coalroller143]

im thinking also it might be the glow plug relay. but i changed out the glow plug relay for a brand new one yesterday. but im not hearing the glow plug relay turning on, and im not sure on what turns the glow plug relay on. So would you happen to know what turn the relay on? i've heard its a fuse. but im not sure on how to check that. would you haooen to know?

[1Dieselman]

The pcm turns the relay on. It supply's a ground to it not power. One large and one small terminal should have constant power to them. As soon as the key is turned on the pcm grounds the other small terminal which should turn on the other large terminal. That is unless the engine is up to operating temp then the pcm will not call for it.

[coalroller143]

how could i tell if the PCM is bad? and if it is what needs to be done to fix it?

[coalroller143]

how do i check if the PCM is bad? and if it is, what needs to be done to fix it?

[Coalrollar58]

i feel like there are other things to do before we can tell if it is the PCM. seems like there may be a simplier fix to fiqure out why the GPR isnt getting the right voltage. it may just be the fuse. but does anyone know if it could be a bad ground someone on the PCM possibly?

[1Dieselman]

Use a test light, find the small terminal that is hot, if neither is hot find the blown fuse in the power distribution box, I don't remember which one it is. Make sure that one of the large terminals is hot. If you are good to this point disconnect the other small terminal that didn't have power and hook the test light to the wire and the other end to a battery positive (since the pcm supplies a ground) turn on key and see if test light turns on. There is a sensor that tells the pcm the engine temp and that may be bad. Only way to fix the pcm is replace it and if that becomes necessary the new pcm needs to be flashed to the code of your old one. I'm not saying pcm's don't go bad but it is rare.