Lift Pump causing power loss?

I have a 2004 Jetta tdi wagon with about 80k. When accelerating at around 2k - 3k rpms there is some studdering acceleration. I thought it was the MAF replaced it and the studdering is still there.

Has anyone had or heard of the lift pump failing gradually? It seems like most people post that they were stranded. I can't think of what else this could be. It certainly seems like a fuel delivery issue. I replaced the fuel filter about 4k miles ago but maybe I'll just do it again. I run both dyno and bio. The problem is admittadly worse with the bio. It has been going on now for about 1,000 miles and has only gotten a little worse in that time. My car runs fine so long as you don't accelerate too much. I can get it to 80mph and beyond but the lack of power when you need it is getting frustrating.

Thanks

I think the biodiesel can clog things up, including the pump workings. I would replace the pump and if you do this yourself, its about $225 from Kerma TDI or TDIparts.com (both vendors on this list). Good insurance. Even if its not the pump, these pumps do not seem to last much longer than what you have on yours, so it most likely will fail soon. Mine failed at 46,000 miles!

--Nate

Thanks PDJetta: Did your pump, or other's, fail completely all at once or was it a more gradual process?

I have read reports of both types of failure modes. Mine was suddenly, at 50 MPH, the engine just quit, without so much an a miss or falter before hand, just like the key was turned off. I was on US Route 1 and I was able to coast off onto a side street and then a parking lot.

I was never able to determine how the pump failed, because the car was still under warranty (the 50,000 mile bumper-to-bumper), and it was towed to VW and repaired (took them a week!), so I was not able to disect the pump, as I would have if I replaced the pump myself.

Two days before this happened I noticed an ever so slightly louder normal pump sound when the key was turned "on", before I started the car. I thought very little of it.

If you have used biodiesel, chances are the pump works are all gummed up and maybe the pump is just real sluggish. I would relace it, regardless, and see if it fixes your problem.

P.S. if the dealer replaces the pump, you will pay at least $800 for it!

--Nate

Thanks again, I'll replace the pump soon, myself. I have no need to part with an additional $600.

you might want to try replacing the filter first - it's a whole lot cheaper and easier. My '04 had the same symptoms after getting a couple gallons of bad fuel at a place I don't usually stop at (thankfully it was only 2 or 3 gallons). Ran OK up to 3k then stuttered. I also only had a couple thousand miles on that filter. I did not notice anything in the filter when I drained it, but I didn't dig into it.
Either way - let us know what you find out... I'm dreading the day my lift pump craps out. I know I should pick up a spare just in case, but there are so many other things that keep needing the $ first...

Sometimes the lift pumps can fail, yet the car will still run. The tandem pump may be working well enough to pull fuel past the dead lift pump. In some cases this results in excessive cranking (2-3second when warm), a rough idle, and sluggish performance.

While replacing the fuel filter would be a good start, check to see if the car can push fuel out of the fuel filter when the key is turned to accessory. If it can't fill the filter, the pump's not working.

Is it possible it's loose injector wires?

Just wanted to let those interested know the problem in the 04 jetta wagon is fixed without a new fuel pump. Unfortunately, I did 3+ things so any of them could have contributed to the fix. (1) I pulled the old pump and cleaned the little plastic screen which seemed a bit restricted and then put the same one back in; (2) I replaced the fuel filer and primed it with power service Diesel Kleen® +Cetane Boost; and (3) I dumped some power service Clear-Diesel® Fuel & Tank Cleaner in the tank (this probably did little).

The tank seemed a little dirtier than I expected. Their was a bit of black residue on the pump and the fuel seemed cloudy when looking into the tank but the fuel that came out of the pump after it was pulled seemed clear. It is possible it could have been the lighting. I must say even though it is possible that biodiesel was partically to blame I am glad I pulled the pump with bio rather than dyno in the tank. I will continue to run biodiesel and maybe swap fuel filters ever 5k - 10k miles rather than the 20k recomended.

I did order a fuel pump and will probably keep it in the car since after asking around it sounds as though these can and do go out unexpectedly.

Thanks for everyone's help, Jon

Check V/B 23 and see if the numbers are more negative more than 60-70 under heavy load-- if they are you engine has a fuel restriction somewhere--filter --pump(s)