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Fuel cuts coming on often now

bostonaudi

Go Kart Champion
Location
Charleston, SC
Car(s)
1995 BMW M3
So, as you've probably seen from my posts, my car gets to the track a lot. About a month ago fuel cuts started happening in hot weather at higher boost settings, now the cuts have gradually worked their way into stock mode, so there's nowhere left to go other than to fix it. Under just mild load now the car will act like the accelerator cable got cut (yes I know there is none), engine loses all power, then I let off gas, then it comes back. Its not a violent buck, it just loses all power.

The low pressure fuel sensor has already been upgraded to newest part (06E906051K), cam follower is fine (just checked it). The high pressure pump is the factory unit, I don't think they tend to fail outright, but I'm starting to believe the low pressure unit in the tank is failing, and it seems to have all the symptoms this article lists:

http://changegears.wordpress.com/2011/01/31/intermittent-fuel-cuts-low-pressure-fuel-pump/

Anyone else have this fail? Seem like reasonable part to replace before I spend the dough?
 

stringshifter6

Nom Nom Nom
Location
Burbank, CA
Car(s)
2007 GTI
That's me in that link. It definitely comes on in the heat and disappears when the weather cools down. A few others here have had symptoms but it's so hard to track because the pump only starts to fail under long distance driving or very high temps. Filling up the tank with fresh fuel tends to cool off the pump and stop the fuel cuts.

Log the low fuel pump pressure to see if output is being maxed out or not meeting specified. I can't find the specific thing to log though, it's somewhere here or on the Ross-Tech site. Do you know what the part number on your pump is? Chris@RT also specified to replace the fuel filter because a failing pump supposedly spits out a lot of crud.
 

bostonaudi

Go Kart Champion
Location
Charleston, SC
Car(s)
1995 BMW M3
That's me in that link. It definitely comes on in the heat and disappears when the weather cools down. A few others here have had symptoms but it's so hard to track because the pump only starts to fail under long distance driving or very high temps. Filling up the tank with fresh fuel tends to cool off the pump and stop the fuel cuts.

Log the low fuel pump pressure to see if output is being maxed out or not meeting specified. I can't find the specific thing to log though, it's somewhere here or on the Ross-Tech site. Do you know what the part number on your pump is? Chris@RT also specified to replace the fuel filter because a failing pump supposedly spits out a lot of crud.

I'm fairly confident its failing now. I just filled it up after the initial post - the gas was into red then, and now symptoms have gone away again, so cooling it off with fresh gas seems to have helped. It started failing 3 weeks ago in Georgia, we were stuck in traffic for a couple hours, it was super hot out and then the cuts began.

Note that the dealer told me the 1K0 919 051 CL part number has been superseded again (CL was a supersede too). I think it's DB now but I'll confirm tomorrow. Will make sure to change filter again too.
 

stringshifter6

Nom Nom Nom
Location
Burbank, CA
Car(s)
2007 GTI
CL has been superseded again? I hope the one I got doesn't end up doing the same thing, I just got it a few months ago.

*Looks like you're right, looking up the CL part number directs you to the DB part number. If you do pick one up, post pictures, maybe we can find some changes.
 

Angel@forge

Go Kart Champion
Location
Orlando
Car(s)
06 A3 sport
My a3 did this during the summer months on long drives or when stuck in traffic. It still ran for years after the first time this showed up with no issues until I had a follower fail. Unrelated to the cuts though. I always assumed it was the low pressure sensor because that was the only thing that would show up on vag com relating to the condition. But since it was so easily isolated to specific conditions I didn't really pursue a fix.
 

bostonaudi

Go Kart Champion
Location
Charleston, SC
Car(s)
1995 BMW M3
That's how it started for me. If I let the gas tank run down and its a hot day it gets fairly bad.

Ordered new pump today, the part has been superseded and it is now 1K0 919 051 DB.

I'll post a pic when I get it.
 

ViRtUaLheretic

╭∩╮(︶__︶&#6
Location
KC MO
Car(s)
2009 VW GTI
Yeah arent our LPFPs submerged?
Extreme hot weather + low gas tank = LPFP not being adequately cooled
 

RRacerguy717

Go Kart Champion
Location
ny tristate
That's how it started for me. If I let the gas tank run down and its a hot day it gets fairly bad.

Ordered new pump today, the part has been superseded and it is now 1K0 919 051 DB.

I'll post a pic when I get it.

Change the fuel filter while your there also with the newer higher bar version. You prob have the early type sump/LPFP that has the inclosed sump. The new style sumps and pump ( comes one piece complete ) is open on the top and its spring loaded versus hang type sump of old. I think around early 2008 cars and up have the open design. Bob G
 

brekdown29

J-O-O
Location
Phoenix
Car(s)
GTI 7.5
This has happened to me only once and it was after 4 hours of driving in 105*+ weather and on low fuel. My shop agreed that it was probably the LPFP but I've yet to do anything about it.
 

bostonaudi

Go Kart Champion
Location
Charleston, SC
Car(s)
1995 BMW M3
This has happened to me only once and it was after 4 hours of driving in 105*+ weather and on low fuel. My shop agreed that it was probably the LPFP but I've yet to do anything about it.

Keep an eye on it as it may get progressively worse like mine.

I think what trashed my pump was a run at Limerock this summer, it was hot and I consumed 2 entire tanks of fuel in one day. The pump likely saw a near 100% duty rate all day!
 
Location
Toronto
had the low pressure fuel code twice now. Once during or after track.. and the second time this week Before track.

However I am only stage one with down pipe. Car has been driving fine and no issues... I felt the engine studder twice on the highway while going to track.. but no issues after that, and drove for 1000km after.. no issues...

Will be doing my next bit of driving and track day in stock mode to see if i can replicate the issue.


Boston why dont you try the proper fueling for K04 now that u've been on stock pump for so long?
 
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bostonaudi

Go Kart Champion
Location
Charleston, SC
Car(s)
1995 BMW M3
They looked the same, except for a plastic screen on the bottom of the new DB pump. I guess my old one is on bottom of tank or was never there.

R&R wasn't too bad. Wear gloves, and have a turkey baster and pail available so you can suck gas out of the pump basin, otherwise you'll spill gas everywhere trying to get pump out. Not sure I'd recommend as a DIY, its a bit messy and potentially dangerous. You're also supposed to use a special tool to get the retainer ring off, but it does pop off fairly easily as in the DIY.

What surprised me a bit is how fast the engine died when I disconnected the pump and ran it dry. If the rear pump isn't 100% you can expect loss of power or cuts.

CL pump:



DB pump:


Extra stuff:
 

stringshifter6

Nom Nom Nom
Location
Burbank, CA
Car(s)
2007 GTI
Hmm so you already had the CL pump and it still died?

As for the DIY, I would not do it in an enclosed area. Do it with the tank pretty low on fuel. The baster is an excellent idea. Just have all your tools ready and whatever you need so that you minimize the time the tank is open.
 

junker

You get an 'F'!
Location
Berkeley
Car(s)
MkV GTI FSI
I'm curious as well... have had this happen on two different long road trips going between AZ and CA in 105+ heat. After the first time, I replaced the fuel filter but it still occurred on another long, hot trip. After the second occurrence I replaced the HPFP thrust sensor. I had two codes both times... I think P2293 and P0087. If it happens again, I was going to try the LPFP...and then pursue warranty due to cam flattening. Really don't think it is the HPFP/Cam, however, since it has only happened twice on long drives in very hot temps. Keep us posted...
 
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