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High LTFT K04 BPY

BurgerGuy

Go Kart Champion
Location
Charlotte
Car(s)
'07 K04 GTI
Smoke test done. Shop found a few leaks:
  • Vacuum connection at N75. They said the screw was hand-turn loose. This was a big one. Fixed
  • At coil pack 1. Could be leaky channels in the valve cover? Small leak
  • Left screw hole for the coil pack harness, but very small. I drove it in too far one time :/
  • Right side of MAF sensor although I was told it would likely not impact the reading since it's before the sensor.
Might be worth looking into replacing the valve cover although I could feel a difference with the vacuum connection on the N75 fixed. Will monitor LTFT over the next few days.
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
Bam! Good finds today, yes? Must feel good having it done with productive results.

I wouldn't be sure on the MAF leaking near the right-side. I think it is close enough to reduce air volume at the MAF.
The coil harness screw...mine doesn't even have screws. It has the holes in both the harness and cover...but no screws. You may want to avoid them with a new valve cover.
 

BurgerGuy

Go Kart Champion
Location
Charlotte
Car(s)
'07 K04 GTI
The tech who does 99% of the work on my car says he added them to keep the coils from "sliding out." I've never experienced this myself, but hey...what harm can two screws do?...lol. If the adhesive for the oil fill neck was weakened then I suspect the channels inside the cover may be as well. A new cover is less expensive than O2 sensors.

As for the MAF, I tightened down the right side a bit more. When checking the left screw, right side was definitely a bit looser in comparison.

It's interesting, each time I fix something or refresh a part that shows notable improvements I find myself surprised because I thought the car was running pretty well before, but it just keeps getting better.
 
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ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
What was your LPFP duty after the new pump was in and working? I don't see this was ever posted.
Trying to help another with a constant 91.8% LPFP duty. They replaced the G410, fuel filter, and LPFP at the same time and the LPFP duty still remains 91.8%. I think it might be a fuel leak, incorrect parts were installed, or the lpfp module.
 

BurgerGuy

Go Kart Champion
Location
Charlotte
Car(s)
'07 K04 GTI
Or maybe the controller. I actually put the MK6 LPFP back in the car because the sending unit for the gauge stopped working again. Plus it was cutting out when the tank was below 1/4. The duty cycle never went to 90% unless it was below 1/4 tank when the Quantum pump was in.
 
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ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
But the duty wasn't always pegged at 91.8% as it was before the swap correct?
I think the guy is going to check, visually inspect for melted casing, his controller first. Then they might swap controllers.

I would never recommend Quantum's lpfp to anyone....that is certain. DW65v perhaps.
 

BurgerGuy

Go Kart Champion
Location
Charlotte
Car(s)
'07 K04 GTI
My LTFT partial is the same with both pumps so I don't think my problems stem from there. I cleared faults and let it climb back up just to be sure. Took a few days. New valve cover is next.

Duty cycle never got anywhere close to 90% with the Quantum pump except for the rare occasion where it would cut out like I described. The car seems to be happier with the MK6 pump anyways. Smoother.

There have been many revisions of the pump controller so if his is tired I would strongly recommend replacing it. It made a huge difference for me. A friend who works at the local VW dealership says when a LPFP or controller starts to go it usually takes the other with it over time. If problems persist after that, then I'd find out what his trims are.

That reminds me, I forgot to adapt the MK6 pump after installing. Oops.
 
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ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
OK...I don't know why but I thought originally, your old LPFP was constantly running at 91.8%

Good point...if
when a LPFP or controller starts to go it usually takes the other with it
...so I will share what your VW tech told you. Because he just installed a new LPFP but not the controller.
 

BurgerGuy

Go Kart Champion
Location
Charlotte
Car(s)
'07 K04 GTI
Don't think I ever logged duty cycle back when I first started this thread, but LPFP pressure kept diving in the high RPMs which likely meant the duty cycle was maxing out in an attempt to keep up. There were other problems at the time then too. If the trims stay high after installing a new valve cover, then I'll pull some more data and see what's happening. Guessing I'll be looking at O2 sensors or that coolant temp sensor you mentioned.
 

BurgerGuy

Go Kart Champion
Location
Charlotte
Car(s)
'07 K04 GTI
New valve cover installed. Can feel a substantial difference on the butt dyno, but LTFT partial still hovering at ~+16. When letting off the throttle I usually get a tschuchuchuchu noise. Since replacing the cover, this is nearly non-existent which tells me that noise is likely associated with leaks in the system since I knew the old cover had at least two leaks on it. I've also seen the engine reach ~25inHg while coasting which is a good sign.

O2 sensors or that coolant temp sensor next? Any other lines that are known to wear out or leak as the car ages?
 
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ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
It went to +16 after clearing faults?
You might consider checking the exhaust side for leaks. If air is sucked in prior to the B1S1 sensor, it will cause a lean reading and report. I say this because of the size of the following list. Either way you'll need to smoke or pressure test both sides...inlet and exhaust sides.

Just in following the air inlet;
_connections of the air box to turbo inlet including the crankcase breather and EVAP.
_all green seals for turbo hose and pipe couplings from the turbo outlet to throttle-body
_holes in the FMIC
_MAP sensor seal
_IAT sensor seal
_intake manifold crack along where it is sealed together
_runner flap linkage to manifold leak
_throttle-body to manifold leak
_oil filler cap seal
_noise pipe system leak including in the firewall
_all tubing connected to the intake manifold including PCV, EVAP, and brake boost
_seals for the valve cover and its bolts
....and probably more.

Probably best to smoke test it and if all is sealed...turn your focus to the MAF and O2s. But consider the possibility of exhaust leaks.
 

BurgerGuy

Go Kart Champion
Location
Charlotte
Car(s)
'07 K04 GTI
Hm, interesting. I've noticed on the colder days that the partial LTFT trims up to +19, but I suspect that's just because the air is more dense. There was also one day when it was warmer and the trims got down to about +11. I can't really explain that one and both scenarios were before the valve cover was replaced.

I'll see if the same shop can test the exhaust system for leaks.
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
Yeah, they should. They can just add a blower to a tail-pipe sealing the other/s and spray all junctions with soapy water...it will bubble where there is a leak. I actually need to do this because my +7% is not because of a leak on the intake side.
 
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