Lift pump voltage

[Chief USA]

With electrical problems pretty much almost anything is possible but in my opnion, this problem recurrs with too much continuity and reliability to be a ground problem. My hunch is that the relay may be on its last legs and gets hot and fails or some other similar symptom hence the short amount of time it works before it fails. It sounds to me like you bypassed the relay and everything worked properly. I think I would replace that relay and drive on. Cleaning up electrical connections and corrosion is always an excellent idea and a requirement of good maintenance and upkeep.

 

[Mschuman88]

Update - looked through the issue with my uncle. It was 3 degrees yesterday here so he wanted to go back to his shop and make a couple of wiring harness ideas and then come back next weekend to wire.

He left me some homework though. We walked through the wiring diagrams you guy sent and asked that I troubleshoot the dead line. I’ll keep you guys updated as I go.

Thanks for all the support.

 

[DavidC]

The key to finding what that Blk/Brwn wire is. Find out what else doesn't work, dash lights,backup lights,radio,heater/ac fan etc.. If that wire lost power there has to be at least one other component that does not work. Seem's trying to find that wire going thru diagrams would take a long time, I briefly looked with no luck.

Dave

 

[Mschuman88]

Ok, update.

I wanted to try to get the truck to my parents which is about 3 miles from my house. They have a bigger garage that works better for work.

I made a jumper wire and jumped the relay. The truck started right up. I had 18 psi and I test drove it around the block - all good.

Decided to take off, about a mile down the road, my fuel pressure dropped again. I tried to get the truck home and it started bucking like it was starving for fuel.

Shut it off again and the fuel pump was still running, just didn’t have any fuel pressure. I think you guys are right about blockage....it’s just weird how it runs fine then immediately stops.

When I turned the key on, all of sudden I had a check engine light. Read the code - p1689. I assume that’s because I’ve bypassed my relay for the fuel pump? Hope I didn’t fry the VP44.

 

[DavidC]

Might be time to drop the tank, check the connections/fittings at the top of the module. You could try the hose to a 5gallon jug and run it almost dry to see what happens before dropping the tank.

Dave

 

[Mschuman88]

Hi all,

Got a response from air dog and will be calling them today with the specific details. Depending on what they do, I’ll plan to drop the tank and do all the work.

Additionally, I’ve been without a vehicle for two weeks. I have been looking for a while for a nice used 3rd gen and last night I purchased an 07 5.9. I’ll still keep and fix the 2nd gen.

What a difference 5 years makes !

 

[Mschuman88]

Dave[/QUOTE]

Might be time to drop the tank, check the connections/fittings at the top of the module. You could try the hose to a 5gallon jug and run it almost dry to see what happens before dropping the tank.

Dave

Dave,

Do you just route the line attached to the sending unit on the tank into a bucket with clean fuel? I’m getting a consistent 0 pressure now so it might be a good way to check off variables.

-Matt

 

[DavidC]

The intake line to the lift pump goes to the bucket. I had to buy some fuel line as what I had wasn't long enough.

 

[Mschuman88]

Hi all,

So I thought I would give an update after a few months of troubleshooting an airdog pump.

After a lot of the help I received on here I went through the In tank sending unit and cleaned the screen and fittings. I also rinsed the tank and reinstalled.

After completing that, I also was directed to change my check valve on the return side of the vp44 by the air dog rep. Completed that.

After all was done I tried the 5 gallon bucket test. The pump ran fine for about 30 seconds then the pump began to sputter and a lot of air was in the fuel. I shut it off and took the pump off and removes the quick disconnect fittings. A lot of metal was in the fuel left in the pump.

It was only after all that work that I was able to get airdog to talk about replacement. They finally sent a replacement pump, I bolted up. I did the 5 gallon test, ran perfect. Added fuel to my tank and fired the truck up - perfect 18 psi. No pressure drops or
Anything. I think the pump was th issue all along.

ThAnks for the help I got along the way!