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Discussion Starter #1
How do you check if you are getting power at the fuel pump? We have spark but the truck is not starting. It cranks and cranks. Can't hear the fuel pump at all. We pulled the fuel pump out and I checked the resistance on the sending unit. It is good. Now I need to know how to check that power is being sent to the fuel pump through the connector. Fuel pump costs $343 so it isn't something my dad and I are just willing to give it a shot. I need to be sure. My dad thinks it is the PCM because we have numerous issues with the truck (another thread on here). I think the fuel pump is dead. It is a 2002 Dodge Ram with the 4.7 V8. It sat most of the winter outside.

Checked the relays and fuses. Even swapped relays and still nothing.
 

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T O P L E S S
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Not being trained in mechanics other than having crap cars my younger days I would:
1. Turn key and listen for it to make a noise. * You did this already and heard nothing
2. Check for voltage at the pump with a meter. Make sure it is on DC and have somebody turn the key. What the actual voltage is supposed to be I don't know because I have an 08 where manuals do not exist.

Other than that I would remove the pump and have it tested, which you kind of did, OR if you suspect the ecm pull the fuse and turn the key a couple of times then replace the fuse and re-do 1-2 OR buy a new pump and hope that is all that is wrong.
Like I say, I'm not a mechanic and this is what I would do. What you decide to do is up to you.

BUT
When it comes to ANYTHING electrical on ANYTHING you are working, ANYTHING, check the fuses or breakers FIRST.
 

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Previously Micash21
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You may be getting power to the pump, but the pump may not be sending enough fuel. That is a typical Chevy problem. The pump still functions, it just doesn't create enough pressure on the rail. I don't know the exact pressure for a 4.7L, but find it and check to see what it is at the rail.
 

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Got 2 Hemis
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If you often run it "down to fumes", it may be gone. I used to make that mistake, 'til it cost me ~$500. Use the meter at the pump, have someone turn the key. It will likely get ~13VDC
 

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Previously Micash21
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That's doesn't mean u have enough pressure. You need to remember that dodge did things different than everyone else. They initiate a ground loop to control and object. So for the pump to work, the pcm has to trigger ground on that circuit.
 

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Tricked out Ram
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Fuel pump pressure is 58psi I think. You can check for power at the relay in the PDC or at the pump on the outer wire on the harness. There are four wires to that harness
 

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I had a random problem where my fuel pump just stopped working. Turned out to be a bad ground at junction #72 or something in the engine compartment at the fuse box....so I ended up adding another ground to the line and it's been working fine ever since.

There are 4 wires going to the pump, 2 are ground, 1 is for the gas gauge (its +), and one is for the main power.

You can test the fuel pump by hooking it up to a 12v source, just try not to make any sparks... :D
 

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Oh, and I bought a fuel pump from UAP for $300 (talked them down to that), and I ended up taking it back when I found it wasn't my problem, they charged a 5% restocking fee I do believe, so like $15 to have it on hand when I dropped the tank was worth it to me.
 

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Previously Micash21
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You need to make sure Ur ASD relay works as well.
 

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Discussion Starter #11
First of all, where is the ASD relay on this truck?

Second of all, we took the pump out and now I have fuel in the fuel rail but it just comes out slowly when I press the schrader valve. So not enough pressure. The truck sputtered a bit today. More life than in the past 3 days.
 

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Previously Micash21
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The ASD relay is in the under hood junction block with the other relays. So now you know that the pump isn't generating enough pressure, now to confirm that you have power and ground at the pump. You said you had a probe, so pull the wiring diagram, and probe the wires. Ensure you have power and ground. I'm assuming you have the pump back in? I would have put 12 volts to the pump manually and see if the pump kicked on. We had an issue with an S-10 at work. A tech put 3 different pumps in it just to find out he had a ground problem.
 

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Discussion Starter #13
I got 0.03V at the fuel pump connector when cranking.

By the way, no label anywhere as to the location of the ASD relay. It says it is in the PDC but I don't see anything ASD or Automatic Shutdown.
 

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Previously Micash21
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The only problem is that you will have a constant 12v on the pump, with no way to control it. Only .03v at the pump when the key is on..... You have an issue not related to your fuel pump then. Test ground.
 

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Redtruck-VA
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On my 03, relay #57 is Engine Control/ASD. Relay #58 is Fuel Pump relay.
I would recommend downloading the manual and making it your friend.
Good luck..
 

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Discussion Starter #17
The only problem is that you will have a constant 12v on the pump, with no way to control it. Only .03v at the pump when the key is on..... You have an issue not related to your fuel pump then. Test ground.
After cleaning one of the grounds on the driver's side frame at the wheel well, the voltage went up to 0.113V but battery was already down to 11.8V anyways. Definitely looks like a ground issue here now. Once I can get a full reading at that connector, then I can see whether or not it is the fuel pump. I am getting fuel at the fuel rail though. Small amount and sometimes the truck sputters. I will also hook up the fuel pump to +12V and see what happens.

On my 03, relay #57 is Engine Control/ASD. Relay #58 is Fuel Pump relay.
I would recommend downloading the manual and making it your friend.
Good luck..
I will check that tomorrow for sure. I have a service manual that I use with the this truck.

I really appreciate the help guys.
 

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Previously Micash21
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No prob, thats why we have this place!!
 

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Discussion Starter #19
Put +12V from two batteries to the fuel pump. NOTHING!!! Took off the PDC and I see one connector with a broken metal tab and amazing corrosion. Still getting only 0.05 to 0.1V at the connector. Swapped #57 relays with a working one and still nothing.
 

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Redtruck-VA
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Put +12V from two batteries to the fuel pump. NOTHING!!! Took off the PDC and I see one connector with a broken metal tab and amazing corrosion. Still getting only 0.05 to 0.1V at the connector. Swapped #57 relays with a working one and still nothing.
If you are putting power directly to the pump and it isn't running then the problem has to be the pump or the ground to the pump. If the PDC is corroded then you also have a problem there. Sounds like you have a couple of things that need attention. I would run a ground wire to the pump and hot wire it to see if it runs. If it doesn't then the pump is probably bad. If you have corrosion and broken connections in the PDC then you need to clean that up and make repairs the best you can. Think outside the box here and hard wire the hell out of it. Or replace the PDC. Good luck.
 
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