Engine not running

1996 DODGE RAM
215,000 MILES • 5.9L • V8 • 2WD • AUTOMATIC
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DAVIDGORDY
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I have a fuel pump shutoff and electrical problem, I have replaced five fuel pumps to no avail. Fuel pressure at rail is 49 PSI, yet when key is turned on fuel pump runs and does not shut off at prescribed pressure of 49-50 PSI. If I cycle the key say 25 to 50 times giving a six second delay between cycles eventually the fuel pump will stop after the key is energized and the truck will start and run fine. But, after it is shut off and cools the cycle starts all over. Another symptom is that while the truck is in a no start condition I get a Data Link Error on the code reader (Autel). But as soon as the problem clears, Data Link is restored and no codes. I have replaced five pumps, purge valve, vapor canister which was bad, all eight injectors and fuses.
Sep 22, 2018 at 3:11 AM
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STRAILER
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Two things come to mind which are the fuel pump relay and auto shutdown relay. I would remove them to check for heat damage. Also here is a guide that can help you test them and the location of the relays also I have included the engine wiring diagrams so you can see how the system works:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Check out the diagrams (below). Please let us know what happens.

Cheers, Ken
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Sep 24, 2018 at 5:46 AM
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DAVIDGORDY
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Already Replaced both. This is the fifth fuel pump and regulator in the truck now.
Sep 24, 2018 at 7:05 AM
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STRAILER
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Both relays? If so please bypass the fuel pump relay (hot wire) to see if the truck starts and runs okay. Connect terminals 30 and 87.
Sep 25, 2018 at 2:30 AM
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DAVIDGORDY
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Bypassed the fuel relay 87 to 30 and it just turns the pump on as if the relay was there and the key was on. Still not turning on coil and injectors.
Sep 26, 2018 at 5:22 AM
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STRAILER
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Can you do the same with the ASD relay? It sounds like the PCM maybe bad. Lets use this guide and the wiring diagrams from above to check the wiring.

https://www.2carpros.com/articles/how-to-check-wiring

If everything checks out I would get a used PCM and replace it. Here is the location and pin out for the computer

Check out the diagrams (below). Please let us know what happens.
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Sep 27, 2018 at 3:07 AM
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DAVIDGORDY
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I have done both.
Sep 27, 2018 at 9:30 AM
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STRAILER
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The data error code is making me think the PCM is bad. If you bypass the fuel pump relay does the fuel pressure stay good and not fall off?
Sep 28, 2018 at 4:51 AM
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DAVIDGORDY
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Stays at 49-50 PSI.
Sep 28, 2018 at 4:54 AM
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STRAILER
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Does it run okay with the bypass? Can you please shoot a quick video with your phone so we can see what is going on? That would be great. You can upload it here with your response.
Sep 28, 2018 at 5:02 AM
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DAVIDGORDY
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It does not start with any bypass. So, no.
Sep 28, 2018 at 5:03 AM
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STRAILER
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Will it run will starting fluid? Here is a guide that can help us, does it have spark?

https://www.2carpros.com/articles/car-cranks-but-wont-start

Sep 29, 2018 at 4:15 AM
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DAVIDGORDY
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No, it does not have spark.
Sep 29, 2018 at 4:16 AM
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STRAILER
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Yep the link error is telling us the computer is having a problem if you have check the wiring I would say the PCM has gone out. I would try a used one and plug it in to see what happens.
Sep 29, 2018 at 4:41 AM
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DAVIDGORDY
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Just ordered one.
Sep 29, 2018 at 7:17 AM
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STRAILER
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Nice, let us know
Sep 30, 2018 at 4:21 AM
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DAVIDGORDY
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Ken, you were correct. The Re man ECM arrived pre-programmed today. I spent an entire five minutes installing it. Said a prayer and turned the key to the on position. The fuel pump primed and shut off as it should so I turned the key to start and it started immediately. It would not idle at first but after keeping it running for one minute with the accelerator until all the fuel components could properly charge and get rid of the air, and also the ECM could make adjustments, All is well. Runs like a champ! Thanks again my friend!
Oct 3, 2018 at 5:43 AM
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STRAILER
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Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help

Cheers, Ken
Oct 4, 2018 at 3:30 AM
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