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Discussion Starter · #1 ·
'99 7.3 fuel pump is not getting voltage. I've checked the fuse and relay under the hood and both are good. Also the 'wait to start' light isn't coming on, therefore the glow plug relay isn't getting fire either. Any ideas? Thanks
 

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Check fuse #30 under the hood. If it is blown, unplug the fuel bowl heater and replace the fuse.
 

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Demon Dually
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How did you test the fuel pump relay? Did you physically remove fuse #30 and test it with a meter? I have seen bad fuses that looked fine to the human eye. The fact that you aren't getting the wts light and no fuel pump power tells me that the fuse is bad and 99.999% of the time it is the fuse blown due to the fuel bowl heater shorting out inside the bowl.
 

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Discussion Starter · #6 ·
I have checked all the fuses, with an ohm meter, and all are getting 12 volts. As far as the relay, I can unplug it and feel it open and close. I've also swapped the relays around. Thanks
 

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Check fuse #30 under the hood. If it is blown, unplug the fuel bowl heater and replace the fuse.
I meant under the dash.

And you are checking for 12V on both side of the fuse, correct.

Easier to pull it out and check for continuity.

Feeling the relay energize doesnt meant the contacters are good on a relay, however swappiing them is usually a good test.
 

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Discussion Starter · #9 ·
I have checked all fuses in both locations, just by checking voltage, not ohms. As far as connections go, I really haven't checked any because I wasn't sure which ones applied. I guess I should have started at the beginning so to speek. I was having a problem with this truck not starting, it would turn over, but wouldn't even try to hit. No smoke out the tail pipe or anything. The fuel pump was working when this problem first started, and I thought I had found my problem, the LPOP was losing prime, I reprimed the system and it started. A few days later, same problem arose. I did same as before as far as priming the oil system, but this time it still wouldn't start. The fuel pump was working at this point, I checked to make sure. At some point, during the process of trying to get it to start the fuel pump stopped getting voltage. So now I have to get the pump back working so I can get back to trying to find my original problem.. Thanks for the input so far..
 

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Demon Dually
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This may not be correct but what about an inertia switch? I have an obs so no switch for me but if memory serves you should have one. Have you checked to make sure it isn't tripped? It should be in the pass kick panel. It could also have a bad connection or be a bad switch.
 

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Demon Dually
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That is the only thing left that I can think of. If the fuse is good and the relay is good you should be getting power to the inertia switch. It may be just a faulty inertia switch. The switch should be the same as one in a gasser so the junk yard is an option. I don't know what the stealer would charge for one of those. Just had a thought. Take the kick panel cover off and tap the inertia switch with the handle of a screwdriver. This should trip the switch. Then with the key on reset the switch and see if the pump comes on.
 

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Demon Dually
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OK let me know.
 

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Discussion Starter · #15 ·
Ok, I've been looking at the wrong relay all along. After a little digging around and looking at a wiring diagram, i've determined I'm getting voltage to the relay but i'm not getting a ground. Looks like the FPC is coming from the PCM and its not grounded. I can take a jumper wire and ground the relay and the FP will kick on.. Any ideas? Thanks
 

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Demon Dually
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In a word. PCM. I hate to say it but it sounds like the pcm has a bad circuit on the board. Your options are to either replace the pcm or you can add a relay to create a ground like the pcm does. Can you start and run the truck if you supply a ground? Are you getting the wts light when you ground it? Check the connector to the pcm. You may just have a bad connection. Test the ground wires going into the pcm and see if they have a good ground. If so then you are back to a bad pcm.
 

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Discussion Starter · #18 ·
The WTS light still isn't coming on and the truck still won't crank, but the no cranking has something to do with my original problem I believe. I'm trying to trace down the wires now to see if I can find out what's up. Anybody know where a good 12v cummins is for sale? ;)
Thanks for the input..
 

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Demon Dually
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Yep no wts light even after grounding the relay tells me the pcm is bad. I would venture to guess that if you replace the pcm you may just solve all of your problems.
 
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