lift pump help

[catnhat]

When i start the truck I have fuel pressure after about 15 seconds the lift pump shuts off and lose all pressure. I still have the wait to start light coming on i  wanted to check the wire out of the ecm  for power to the pump but I am not sure which wire it is. Any help would be helpful 

[Me78569]

Your raptor is just plugged into the OEM plug on the side of the block right?  

 

 

Have you checked for power at the raptor itself?  The raptor pump is known for leaking, shorting, and dying.  So if you haven't checked for power at the pump I would do that first. 

 

Here are all the ecm wiring diagrams

http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/26-engine-systems/87-dodge-ram-turbo-cummins-24-valve-engine-wiring

 

Looks like pins on the ecm 35 & 15

 

However I am gonna say you really need to put the pump on a relay, run the power lead from the ecm into pin 86 on a relay, pin 87 goes to lift pump, pin 30 to battery, ping 85 to ground.  issue with just plugging hte pump into the oem plug is if there is any spike in draw fro the lift pump, you can burn up the ecm.  You really shouldn't put that much draw on the ecm.

 

Edited November 15, 2015 by Me78569

[catnhat]

Yes it plug in the oem plug. what do you mean check for power at the raptor and you saying I should put the pump on it its own power with a switch 

 The pump could be on its way out after all this now I am only see 15 pounds 

Before this I was seeing 19 

[Me78569]

I would trace the wires coming out of the raptor, then check power at that plug, while idling, to verify that you have 14v.  

 

For any large amp draw ( raptor pump) you should use a relay,  a relay is pretty much an automatic switch, the ecm would trigger the switch ( by the 12v power it currently does), but the power is draw from the battery directly for the lift pump.

 

 

 

[dripley]

That's how my AD went. Started with lower pressure and then started popping fuses. While mine is connected to the ECM harness it runs thru a relay and only uses the ECM harness as a trigger for the relay. This takes the load off of the ECM. The relay is powered from a separate 12V source. This also allows the fuel pump to be controlled by the ECM.

[Mopar1973Man]

Popping fuses tells me there is issues with motor drag. The motor is drawing more and more power to keep pumping.

[dripley]

You can pull the wire off of the pump and check and see if you have 12v there. just bump the starter and you should have 12v power for about 25 seconds. You could start the truck then pull the wire and you will have 12v until you shut it down. If you have constant power then the pump is shot.

[Me78569]

yep,

 

Typically you will see diesel leaking from raptor around where the wires come out.  

[catnhat]

I don't have deisel leaking I will check the plug for power next 

Ok did  bumping the starter I get 12.3 truck running with heater turning on and off I am between 10.3 and 9 truck runs for 30 seconds checked with a stopwatch and I lose pressure  and all volts going to the pump 

[catnhat]

So something is telling the pump to turn off?

[JAG1]

I only want to say that you should have constant 12-14 volts going to the pump after the truck is running. Voltage will fluctuate if the grid heaters are cycling so wait till the grids stop cycling and then see what you got. But most importantly get the lift pump powered off the batteries before you ruin a $1,000 ECM with a potentially bad lift pump that causes too much draw.

[catnhat]

It's getting cold up here and I can't keep the pump running long  enough  for the heaters to quit running 

[JAG1]

I don't know if it will damage anything but, can you disconnect the pump from the factory ECM connection and wire the pump directly to the battery? That way you can run the truck longer, have fuel pressure and also check the ECM Wire connector for constant voltage while running.

 

I don't think it will damage anything that way as lots of guys have wired their lift pumps directly to the battery on a manual switch. It's not good to leave it that way though because you can burn up your VP if you ever forget to turn on the lift pump.

Edited November 15, 2015 by JAG1

[Me78569]

That's what I would do.

 

Connect the raptor right to the battery and see if it will run so long as it has power.

 

 

Edited November 15, 2015 by Me78569

[catnhat]

Ok I will try that just have to pick up wire

 

[JAG1]

Just cut an old extention cord for wire that works

[CSM]

1 hour ago, JAG1 said:

Just cut an old extention cord for wire that works

Don't plug it into the wall though.  Just use it as a jumper from the battery!  

 

 

 

 

 

 

[JAG1]

31 minutes ago, CSM said:

Don't plug it into the wall though.  Just use it as a jumper from the battery!  

 

31 minutes ago, CSM said:

 

 

 

 

 

 

Only talking about a little AC noise he he he

[catnhat]

Ok got it done the strange thing is that with my vm in the oem plug the volts never dropped to zero like it did before stayed at 13.7 after the Heaters where done. Pressure  has always been at 19 and now it is at 15 and started to fall got to 12 and a saw Smoke coming from my jumper wire so I shut it off. Jumper wire was 18x2 wire off a old lamp 

[JAG1]

My Raptor pump is getting weak just about like that also. When It was about two years old the pressure had to be adjusted back up to 19. Others said the same thing.

The older Raptors had a screen that was on the inlet side that would plug up. Pull that out if yours has this.

It is the proper set up is to have the pump run by the batteries switched thru a relay by the ECM, but another important aspect is to have an accessible/ changeable filter on the suction side of the pump to stop sediment damage to the pump and keep it clean.

I had to drop the tank to get the intank screens removed from the fuel module as they do get clogged over time. That way the prefilter could do it's work. Also in the module is a small plastic cylinder shaped piece on the bottom of the draw straw, take that screen out also.

Edited November 16, 2015 by JAG1