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High LTFT K04 BPY

BurgerGuy

Go Kart Champion
Location
Charlotte
Car(s)
'07 K04 GTI
As the title states, I float between a LTFT of +14% - +18.75. The car runs well, but fuel economy sucks. Running Unitronic Stage 2+ with RFD. Injectors, FPRV, rail sensor, and thrust sensor have been replaced to fix other issues. So far I've...
  • Checked for and fixed two intake leaks (trim readings did not change after doing this)
  • Replaced MAF sensor (improved drive-ability/response)
  • Replaced IAT sensor (¯\_(ツ)_/¯ )
Also ran some logs which I've attached. At high RPM, LPFP pressure drops below 3BAR. Will have to log another run with requested LPFP pressure to see if it's really falling behind. Other than that, potentially the front O2 sensor? What else could create a lean condition besides intake leak, tired/bad sensor(s), or fueling issues?
 

Attachments

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
With leaks sorted...I suspect low fuel pressure or dirty fuel injectors. O2 is a possibility, but you need to decide what you will sort out first to last. Given the data for low fuel pressure, is why I suspect fuel pressures mostly. But I would also look at the rail pressure before any further steps are taken.

You may recall my "partial/off idle" trims were once 17% or 18% and a leak I found and fixed dropped it to 7% or 8%. I just upgraded my LPFP but have yet to run data for the fuel trims and lpfp pressures. Mine did drop to 3.5 bar when last checked over a year ago. So I hope to see better pressures and a drop in partial trims. Post data for the fuel high pressure...also the lambda and we can go from there. Rail pressure may not point to anything, but we can see if target pressure is met, this may point to clogged injectors. But if rail pressure target is not met, then the low pressure is more likely the problem. However, either scenario is telling you the lpfp needs to be remedied.
 

BurgerGuy

Go Kart Champion
Location
Charlotte
Car(s)
'07 K04 GTI
Injectors are new. The log I attached shows rail pressure drops ~2 bar at the same time LPFP pressure drops from ~4.4 bar to ~2.7 bar while rail pressure isn't able to meet specified except for a spike at ~5600 rpms. LPFP duty cycle also spikes to 91.8%. My guesses are:
  1. There's a leak I haven't found yet which is putting additional strain on the fueling system and since it's running a K04 it's already tuned to/near its limits.
  2. There's a bad sensor, likely front O2, throwing off the reading.
  3. The LPFP just isn't cutting it.
So you're not running the TTRS pump with a PM3 anymore? That was my plan, run the TTRS pump with a PM4 and be done with it. Are there better options? I've an updated GTI basket which will let me transfer the sending unit to the TTRS basket. Just need to find something to plug the extra fuel pick-up line. Would an upgraded LPFP solution require tune adjustment? I've read the PM3/4 plays nice with the ECM.
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
Injectors are new. The log I attached shows rail pressure drops ~2 bar at the same time LPFP pressure drops from ~4.4 bar to ~2.7 bar while rail pressure isn't able to meet specified except for a spike at ~5600 rpms. LPFP duty cycle also spikes to 91.8%. I do not see rail pressures in the attachment above. LPFP or low pressure shouldn't fall below 4.0 bar. In MB 231, it shows the LPFP target and that never goes below 4 bar. Duty cycle max is always 91.8%...this does mean the LPFP is working at its fullest, yet not reaching target pressures and you are seeing the rail pressure dip a bit. If the lpfp was working well, the duty might still be 91.8%, but the target pressure would be met by actual pressure. Again, since you see pressure in the rail drop...the LPFP might just be responsible for some of the lean reports causing the additive.

My guesses are:
  1. There's a leak I haven't found yet which is putting additional strain on the fueling system and since it's running a K04 it's already tuned to/near its limits. Sure, it is possible a tiny leak still exists.
  2. There's a bad sensor, likely front O2, throwing off the reading. The O2 volts should be below 1.5v in MB 033 block 2. If it is above 1.5v...you can expect to find a leak.
  3. The LPFP just isn't cutting it. True
So you're not running the TTRS pump with a PM3 anymore? That was my plan, run the TTRS pump with a PM4 and be done with it. Are there better options? I had the High Flow pump by USP(I don't think they still have it and I never found out which it was from). It cost $100 more than the TTRS. It fould the fuel levels on the fuel gauge(never reached Full and ran out of gas when showing 1/8 tank) and it didn't do anything with fuel pressures until I switched from GIAC to Driver Motorsports tune where fuel pressures could be custom set within the tune. When I added the PM3, I removed the High Flow LPFP, installed the PM3, returned to the GIAC tune, and reinstalled the old oem LPFP. This ran fine and kept actual low pressure above 4 bar. But not for long...just 1.5 to 2 years. I've an updated GTI basket which will let me transfer the sending unit to the TTRS basket. Just need to find something to plug the extra fuel pick-up line. Would an upgraded LPFP solution require tune adjustment? I've read the PM3/4 plays nice with the ECM. I think the PM4 is tune'able, isn't it. Either way, No, you do not need a tune adjustment, because the PM4 provides more amps to the pump. Tuning is only required with oem amps and still you might not see much if any of an improvement because another pump like TTRS is only going to reciave 15 amps max. Thing to remember is the oem circuit is a 15 amp circuit and the TTRS runs on a 30 amp circuit. This could be because the TTRS has two pumps though.
Anyhow, I replaced the pump with a Quantum 265L/hr. It cost $80 w/lifetime warranty where DW65v costs $250 w/3 yr warranty. The quantum pumps better on lower amps as well. You'll see the testing I found in the posts I linked. ↓

This is what I did last week...
https://www.golfmkv.com/forums/inde...-pump-in-basket-swap-help.192233/post-7421158

..and this.
https://www.golfmkv.com/forums/inde...-pump-in-basket-swap-help.192233/post-7422299
 

BurgerGuy

Go Kart Champion
Location
Charlotte
Car(s)
'07 K04 GTI
Anyhow, I replaced the pump with a Quantum 265L/hr. It cost $80 w/lifetime warranty where DW65v costs $250 w/3 yr warranty. The quantum pumps better on lower amps as well. You'll see the testing I found in the posts I linked. ↓

This is what I did last week...
https://www.golfmkv.com/forums/inde...-pump-in-basket-swap-help.192233/post-7421158

..and this.
https://www.golfmkv.com/forums/inde...-pump-in-basket-swap-help.192233/post-7422299
So I could run the Quantum pump with the OE controller? I have the latest revision which was installed Q4 last year. $80 is much easier to swallow than $1k+...

What has your experience with the Quantum pump been so far?
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
So I could run the Quantum pump with the OE controller? I have the latest revision which was installed Q4 last year. $80 is much easier to swallow than $1k+...

What has your experience with the Quantum pump been so far?
Yes, absolutely, you can. If you look at the test results for the HFP-A35HV (Quantum), our controller is only able to provide 92% duty, and 92% of the LPFP circuit of 15a is 13.8a....keeping that in mind, our max target pressure is 6.6 bar or 96 psi. Now find 95 psi on the test results and you'll see the amps required is 11.1a. You'll also see the DW65v requires 12.8a to make 95 psi. Both will work, but I see in the results that the Quantum should make target pressures more easily. I believe when I ordered mine, it was here two days later.
I'll leave this here; https://www.highflowfuel.com/i-2831...lkswagen-gti-2-0l-replaces-airtex-e8424m.html

I have driven it three times...I notice the car starts more instantly like it did when new...no subtle stumbling before ignition. I notice there is no stumbling(albeit was minimal prior to replacement) when back on throttle lightly when daily driving. I am curious to have a look at the data still, because wanting to see it retain pressure above the 4 bar minimum target, but I am sure it will do so. I did pull it hard once. I didn't notice more power, but it felt to accelerate smoother. So, basically I notice a smoothness when on the throttle lightly or heavily. I didn't even realize the slight roughness it had prior to the swap. Data is the main goal though, so I'll see soon.
 
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ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
After some thinking on this or that ↑, I imagine I felt no more power because the final delivery is the rail pressure and my actual was able to be a bit higher than target last few times I checked. I still have new injectors to install and perhaps I will feel something more then.
 

BurgerGuy

Go Kart Champion
Location
Charlotte
Car(s)
'07 K04 GTI
This is great info. I didn't understand the voltage to pressure requirements for the pump to do its job.

Sounds like your car is running healthier. I'm going to give this pump a go myself. Check out the log I ran today (tabs in spreadsheet show graphs)...LPFP specified is 4.56bar, but the pump is never able to achieve that pressure and eventually drops off at high RPM. Duty cycle pegs to 91.8% at the same time. Seems pretty obvious the pump is the culprit here.
 

Attachments

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
I think so....it just constantly drops pressure at full duty. You'll typically see a different LPFP target pressure due to temperature...but never should the actual drop below 4 bar. I say that, again, because the data never shows the target pressure for the LPFP to be below 4 bar. The new pump should keep actual pressures where it specifies it to be. If you get it and go to install it and have any questions...you'll find in your messages a link to my fb page.
 

BurgerGuy

Go Kart Champion
Location
Charlotte
Car(s)
'07 K04 GTI
I bought the pump. Also, your FB link doesn't work, but that might be because I don't have a FB account 😬

I think so....it just constantly drops pressure at full duty.
The Quantum pump drops pressure at full duty or the OE pump did?

You had mentioned not being able to see data after installing the pump. I use Polar FIS for real-time monitoring right on the MFD. The MKV uses the PF04 and is very easy to install. Lots of customization options. I can monitor rail pressure, LPFP pressure, DC, and fuel trims from one screen. Only down side is VCDS doesn't like sharing the CAN bus with the Polar FIS, but that's easily fixed by switching to any other MFD screen than the Polar FIS.

Are you able to see rail pressure and LPFP data in the most recent log file I posted?
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
I bought the pump. Nice. Also, your FB link doesn't work, but that might be because I don't have a FB account 😬 I'll continue checking here then.



The Quantum pump drops pressure at full duty or the OE pump did? Not mine, yours. I explain below.

You had mentioned not being able to see data after installing the pump. I have VCDS and VAG-COM cable. I just haven't logged the data. I've only driven the car twice since, and just haven't done the data log. It wasn't running badly or anything like that, so I have no worries of whether or not I fixed something. Just need to log data because I would like to see the difference before I install the new injectors. I use Polar FIS for real-time monitoring right on the MFD. The MKV uses the PF04 and is very easy to install. Lots of customization options. I can monitor rail pressure, LPFP pressure, DC, and fuel trims from one screen. Only down side is VCDS doesn't like sharing the CAN bus with the Polar FIS, but that's easily fixed by switching to any other MFD screen than the Polar FIS.

Are you able to see rail pressure and LPFP data in the most recent log file I posted? Yes, and I too believe your LPFP is ↓.
Sorry, should have quoted more accurately. To your statement; "Seems pretty obvious the pump is the culprit here." I replied; "I think so....it just constantly drops pressure at full duty."
 
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BurgerGuy

Go Kart Champion
Location
Charlotte
Car(s)
'07 K04 GTI
Lol that makes way more sense. When installing the Quantum pump, how did you secure the pos/neg wires to the terminals on the pump itself? Could I solder it (ensuring it's all dry and what not so I don't start a fire)? Other option would be to use a set of spades.
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
Lol that makes way more sense. When installing the Quantum pump, how did you secure the pos/neg wires to the terminals on the pump itself? Could I solder it (ensuring it's all dry and what not so I don't start a fire)? Other option would be to use a set of spades.
The oem "clips/female connectors" are an exact fit to the Quantum posts...if the female clips are attached to your wires still. Also, the two are different sizes so you cannot connect them incorrectly.
 

BurgerGuy

Go Kart Champion
Location
Charlotte
Car(s)
'07 K04 GTI
Got the pump, but uncertain if it will fit into the basket the MK6 GTI uses. Check images below. The positive/negative terminals are soldered to the pump itself. The pump also looks shorter than the one I got and does not appear to fasten to the bottom of the basket. The pick up on the bottom of the assembly is also off-center.

Might just need to pick up a used FSI pump (1K0919051AQ) and swap it out which will work nice because I can get that done, then swap it all out at once. The LPFP I have on the car now is 1K0919051DB.

IMG_20200422_174903.jpg
IMG_20200422_174754.jpg
IMG_20200422_175125.jpg
IMG_20200422_144117.jpg
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
That design looks exactly like the High Flow(HF) I got from USP years ago. I wanted to see if the HF pump would swap over into the original basket and I literally ended up busting the HF pump's cage to remove it. It has the exact same filter panel attached to the bottom. And now I have a $600 pump sitting in the garage with no use of it.

Like yourself, I do not believe the new pump will fit that basket because I'm pretty sure the bottom of the baskets differ as well as the tops as you mentioned.

There are posts here but I remember people saying they had to remove the clips holding them pump in place to remove that pump from the basket you have.

Have you ever changed the controller/PWM?
It may be the control module is heating and has not yet reached the point where it shuts the engine off. It is possible it may be failing and is not widening the pulses as it should at higher duty demands.

I hope some good comes from my misunderstanding your current basket design. That is pretty much a new oem MK6 pump correct? Can you contact Quantum real quick to ask about their return? Let me know how it goes please.

Try making contact with high_octane3541 @ https://www.golfmkv.com/forums/inde...-fueling-setups-solutions.185862/post-3792921 ..for questions about removing that sort of pump from the basket if you choose to continue.
 
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