ISSUE SOLVED: ID Parts Lift Pump installation guide issue

[D-cappz]

Attention ALH owners that have installed a PD lift pumps or are going to install a PD lift pump. If you have used the ID parts installation guide, you may need to change the ground that comes from relay 53 that they suggested in their instructions. https://www.idparts.com/pd-in-tank-lift-pump-install-kit-p-911.html

I had my PD lift pump installed for almost 2 years prior to any noticeable issues, it did not start to show signs of something wrong till 2 years later.
Every so often my car would stall during idle, never under throttle. I noticed the fuel line had air/foam in them every time this happen. It then would take a while to crank over and finally run again. Now this was not an every day occurrence, but it gradually got worse and worse.
I noticed that the fuel pump would not run all the time, and then noticed that once the car was cranking over or running the fuel pump relay was rapidly turning on and off which in turn the pump was doing the same or just not turning on.
Here is a video of the relay and the instruction from ID parts.
VIDEO: https://www.youtube.com/watch?v=nycgTdz-jXo

This was solved after I posted on a couple Facebook TDI groups. (VW TDI Owners) LINK

Montgomery Schrader sent me a private message asking if I had used the ID parts install guide when installing the PD lift pump (which I had). He informed me that he had the same issue and that the ground that ID Parts instructed to use has a 100ohm resistance which causes a grounding issue. I decided to check if this was the issue by jumping a new ground, and sure enough that fixed the issue of the relay turning on and off rapidly.

I then ran a new ground from the lift pump relay to under the battery where all the other ground run to and i have had 0 issues since.

If you have done this install and fallowed the ID Parts installation guide, i'd suggest checking to see if your relay is chattering on and off. Just to be safe, run the extra 2 foot of wire from the relay box to under the battery trey to the other grounds.

I hope this helps others solve an odd issue.

Thanks so much for those of you that gave some great input/ideas.

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[cuban11182]

I just installed mine today. Mine was an auto, so the relay bank is not in the engine bay. I ended up using a ground inside the car under the dash. If I start having issues I will run a new ground. Thank you for this info.

 

[wonneber]

I then ran a new ground from the lift pump relay to under the battery where all the other ground run to and i have had 0 issues since.

If you have done this install and fallowed the ID Parts installation guide, i'd suggest checking to see if your relay is chattering on and off. Just to be safe, run the extra 2 foot of wire from the relay box to under the battery trey to the other grounds.

This sounds like you have/had a bad ground somewhere in the car, possibly the one under the battery tray.

While you were adding the ground under the battery tray did you take all the wires off and clean the connections?
If that point had bad connections then everything that grounds to the body is bad.
I'm guessing ID-Parts has the relay grounding under the dash?

 

[wonneber]

I just installed mine today. Mine was an auto, so the relay bank is not in the engine bay. I ended up using a ground inside the car under the dash. If I start having issues I will run a new ground. Thank you for this info.

If the ground under the battery tray is good then the ground under the dash should be good.

 

[D-cappz]

This sounds like you have/had a bad ground somewhere in the car, possibly the one under the battery tray.

While you were adding the ground under the battery tray did you take all the wires off and clean the connections?
If that point had bad connections then everything that grounds to the body is bad.
I'm guessing ID-Parts has the relay grounding under the dash?

The grounds were all very clean under the tray, since I ran the found under the battery tray, I've had 0 issues with it.
ID Parts has you ground in the relay box above the brake master, and to the glow plug relay ground I believe.

 

[gmenounos]

Looking at the wiring diagram for a '99 ALH (other years probably the same), the black "ground" wires in the relay box are not true ground wires. They go to one side of the coolant glow plugs and the other side of the coolant glow plugs go to ground. So, there will always be some resistance between those black wires and ground.

 

[pkhoury]

Gotta love those of us who respond to old threads. I recently did this on my 2002, and have the pump installed (but not the wiring) on my 2000. I used used chassis ground for my pump, and I think the 53 relay is using the same, so I have no problems on my end. I used the install as a reference, but for the most part, I did the wiring job to the beat of my own drum, so to speak.

 

[gmenounos]

and I think the 53 relay is using the same

Nope. Both 53 relays inside the black relay box in the engine compartment ground themselves through the coolant glow plugs so they're not very good grounds for other electronics. And if a coolant glow plug were to burn out or if the wire to a coolant glow plug were to fall off or get corroded then they wouldn't be a ground at all. Best to run a separate ground wire to the chassis for the lift pump relay as noted by the original poster. I was just adding to this old thread to explain why the black wires inside the relay box are not true grounds.

 

[pkhoury]

Let me rephrase - my 53 relay is grounded to chassis ground. I misclarified. The instructions have you use the coolant glow plug wiring, but I opted for chassis ground for the same reasons you mentioned. I was also chatting with @burpod , who suggested relays inside the car. I mounted mine next to the coolant GP relays for convenience sake, but I might try and do it inside the car on the 2000, though there's then the problem of it continuously running when flashing a new ECU tune (and the fuse was a little more accessible next to the coolant GP relay area.