LPFP Problems?

[judunty84]

I have been having issues with stuttering under load through the middle of the RPM curve. Checked a million things so far but no solution. Did some logs a couple weeks ago and everything looked good, fuel pressure, boost, n75...when it would stutter it was pulling massive timing i.e. -8* which is the only thing that looked off.

Tonight we logged LPFP duty cycle at idle and made a couple 3rd gear pulls. The duty cycle at idle was in the 48-50% range and at WOT it would reach 85%.

I searched and couldn't find what the duty cycle should be. Right now we are leaning towards a clogged fuel filter or the LPFP going bad.

Speaking of the LPFP where can I get one and how much do they normally cost. I couldn't find any online unless I can run a walbro 255?

Thanks.

 

[160hunter]

Here you go. http://www.ecstuning.com/Volkswagen-Golf_V--2.0T/Engine/Fuel/

 

[judunty84]

Here you go. http://www.ecstuning.com/Volkswagen-Golf_V--2.0T/Engine/Fuel/

The only two lpfp's I see are the Bosch 270 and the Walbro 255. I couldn't find the stock replacement.

 

[07bunny]

Usp has drop in upgrades and then leaves you the option to upgrade from there even, and the duty cycle will continuously change because our fuel system is a return less system so it goes on the demand of we're your foot is at

 

[Ratchet]

from what ive read, you dont want to run the higher end pumps like that. VW has made revisions to the LPFP, your better bet is to contact 1stvwparts.com

 

[bostonaudi]

What typically happens is a fuel cut, then engine comes back. VW has superceded the part number for 2nd time, new is now 1K0 919 051 DB. Mine started going south when it was hot out and and I ran the tank low, it would then cut. A fresh tank of cool fuel would eliminate it.

The DIY isn't too bad, there is requirement for a special tool to properly torque the retainer ring, but it can be done with hammer and screwdriver (which was all you needed for the old Bugs lol).

DIY:

http://www.golfmk5.com/forums/showthread.php?t=129924

Like any part for your car, you can get one at the VW dealer. I think it went for around $200.

 

[cruizin01]

Did you log fuel pressure?

 

[bostonaudi]

Did you log fuel pressure?

In my case no, when symptoms went away with a tank fill, I was reasonably sure it was the LPFP going bad. I replaced it and its been running like a champ ever since. I found other threads that exactly described the same symptoms I had as well.

 

[cruizin01]

In my case no, when symptoms went away with a tank fill, I was reasonably sure it was the LPFP going bad. I replaced it and its been running like a champ ever since. I found other threads that exactly described the same symptoms I had as well.

in your case yeah I wouldn't have gone any farther either. Its somewhat obvious. I was more questioning the OP.

 

[judunty84]

in your case yeah I wouldn't have gone any farther either. Its somewhat obvious. I was more questioning the OP.

I did log fuel pressure and it looked fine. I can upload a graph from home since i am at work right now. I did just hear from Arin and he said at idle the duty cycle looked ok. He said a fuel pump going bad would be oever 60% at idle, so right now I am back to the drawing board?

Frustrating!

 

[Barretoc]

Sorry to bring back such an old post. My car is stuttering around 2500 rpms 3-6th gear. Only happens when trying to build boost. Not sure it's it's the lpfp. It's not throwing any codes so I have absolutely no idea.

 

[Red5pade]

Sorry to bring back such an old post. My car is stuttering around 2500 rpms 3-6th gear. Only happens when trying to build boost. Not sure it's it's the lpfp. It's not throwing any codes so I have absolutely no idea.

lpfp usually wont throw codes, its usually hidden in logs like horrible a/f ratio which tells you to log the electric pump... i forget which block that is tbh

fuel cuts in that range could be the hpfp but i doubt it is the lpfp unless its really bad. remember anything on the lpfp workload over 70% means its bad

you may be having misfires too, so you could look in that direction too. good luck

 

[Barretoc]

lpfp usually wont throw codes, its usually hidden in logs like horrible a/f ratio which tells you to log the electric pump... i forget which block that is tbh

fuel cuts in that range could be the hpfp but i doubt it is the lpfp unless its really bad. remember anything on the lpfp workload over 70% means its bad

you may be having misfires too, so you could look in that direction too. good luck

I've had a misfire on one of the cylinders but it went away and hasn't come back since. it will stutter 1-3 times in the rpm range from 2500-3000

But I'm not sure what you mean by the workload on the lpfp

 

[high_octane3541]

But I'm not sure what you mean by the workload on the lpfp

duty

 

[Barretoc]

Car is now mAking a popping noise. Not sure if it was there before but just noticed it.