Boost Freaking out and high fuel pressure target is just 110 bar

[ROH ECHT]

Below is a "copy-n-paste" of five posts of mine from a thread of mine on another forum over the past five days. I am beginning to doubt I can solve this one but lean towards it being catless.

It is a MK5 GTI FSI w/K04 and all necessary mods, no codes, LTFT is +6.6%, just today installed my new LPFPw/internals and set Forge WGActuator preload to near zero.

(Saturday) So...I've been driving quite mildly for some time but last night I gave a ride to someone at the Friday Night GTG. I notice my boost, and it peaked at about 24-25 psi and then dropped to nearly 15 psi before beginning to climb again. Today, while at C&C, I was giving a ride to a club member to look at the boost situation. Boost went up to 24ish psi and dropped again...then another pull it peaked, dropped below 15 psi, and then bounced up and down between 10 psi and 20 psi. We both also heard the boost leak from the DV(AWE) while building boost during the second pull. This shouldn't happen as the AWE-DV spring is rated for 30+ psi. Later, I get home, pop the hood and give it a look over to see if I see anything obvious but do not, and grab my laptop and plug in Vag-Com and go do a couple data logs. I watch the boost gauge while doing so and it looks normal'ish again. Only, it doesn't peak as high and also drops to 17 psi and data confirmed a peak of 21.5 psi and drop to 17.5 psi. Normal has been peak=22.5 psi and drop to 18.5 psi...so it was close in the data. My wgdc went to 97.3% for a period of 400rpm (2400 to 2800 rpm) and then dropped until it reached mid 30% about 1k rpm later, at 3600 rpm...and climbed back to 52% by redline.

Seemingly normal, right? But leaves me wondering "WTF" was going on? I went looking at the engine bay again...checking many connections, tightening clamps, looking for oily residue at connections, and so forth but find nothing obvious. I may reverse my AWE DV so that the presence of boost will press the DV closed in order to eliminate the DV spring as the source of weirdness should the condition reappear.

Not sure yet if I should add or subtract WG preload just yet...or even if I should attempt installing the blue Forge WG spring but not confident this will fight the N75 and ECU as it may not want to open until 28 psi is reached. Right now there isn't much preload on the actuator. My forge WG actuator peaks boost at 20.5 psi with the yellow spring and zero preload. I have just 1.5mm(turns) of added preload right now. I also have a newish N75 with probably just 13k miles on it. The new N75 solved a very similar issue when I replaced it. Then, the symptoms were that my boost was just reaching 18 psi, dropping to below 10 psi quickly after hitting that 18 psi and then climbed back to about 15 psi.

The PCV is new and last revision available.

Anyway, if you feel like mulling this over...my plans are to do a pull from time to time and when the condition reappears I will reverse the AWE-DV. If this changes nothing...I will eliminate all preload to see if less boost solves it which may point to a leak I need to detect. If that changes nothing, I will add 2mm to 3mm of preload and see if more preload helps.

Vacuum line and boost plumbing tests are likely coming, but gonna get through those other steps mentioned first.

(Tuesday)  It's like the ECU is fighting the Forge WGA w/yellow spring...but it shouldn't be because I just did the whole setting the preload at zero and boost peaked at 20.5 psi. Then I added just 1.5mm(turns) of preload and boost seemed perfect peaking at 22.5 psi and drop to 18.5 psi late last year.

Now it seems to be trying to retard the peaking of boost more than it did after I set it there last year in the Fall. It is noticeable mostly when there is more load...like from a pull beginning at low rpm's for data checking but I still am seeing quite a drop in boost when I just floor it and it kicks down a gear; boost peaks, but quickly drops down to about 15 psi on the gauge, and then climbs to about 17 psi. Then, it shifts, boosts peaks, and then drops again rather quickly. Like it doesn't like how quickly boost comes on and reduces it drastically. WGDC last year after setting the preload would only drop from the 90% range to about 50%...and now WGDC drops into the mid 30% range.

I reversed my AWE-DV to a "PULL" orientation and drove today and it does the same thing. So I do not think my DV was losing boost in its standard "PUSH" orientation. I think I will return the DV to its "PUSH" orientation as it seems to be what many "builders/race shops" state they prefer, including AWE, for a sensitive MAF system w/DV.

I am going to rest preload to near zero tomorrow and see if that helps. But I will pay more attention to rpm's and the clutch because I may just be focused more on the boost and ignorant to slight signs it may be the DSG clutch...so thanks, I will post again soon when completed with the preload reset followed by a drive.

(Today-Wednesday)  I thought that since my high fuel pressure target is still 110 bar...I would go ahead and install the new HPFP w/Autotech internals today. Just to see if the older APR hpfp regulator is responsible for that and to see if it has any correlation to the boost reduction. So the new hpfp is in...but I need to go out and check fuel pressure targets and actual's and then what boost is doing differently if any.

OK, new hpfp did nothing to fuel pressure target as it remains at 110 bar. Boost data peaked at 22.3 psi and dropped to 17.7 psi, however, my gauge reading was 24 psi and dropped to 16 psi.

Then there's this; WGDC looked like this from 2500 rpm to 4100 rpm...where the other day it only dropped into the 35% range;
97.3
97.3
97.3
97.3
78.8
69
80
18
7.5
0.8
25.5
26.7
31
36.9
35.3
40.8
42.7
41.6

Well, I reduced WGA preload to just 0.5mm(1/2 turn) and boost still peaked about 21 to 22 psi but then dropped and went below 15 psi this time. Didn't collect data but was watching the gauge. All I can think of which I haven't addressed is the Catless factor while running this GIAC K04 HO tune. I have an angled O2 spacer and have no codes for the O2 since installing the angled spacer.

I have trouble believing the problem is injector based. LTFT was 6.6% last check a few days ago and there are no misfires. But I do think of it from time to time because the fuel pressure target has been 110 bar since reloading the GIAC tune after the DM tune was run. I am still led to think it is the Cat removed because catless, and the Forge WGActuator, is the only thing different on the car from when it ran with the GIAC to DM to GIAC. The Cat was removed and the Forge WGA was installed during the time I was running the DM tune. 

[Dan_FR]

Its the actuator. Why have you changed it? These ECUs are incredibly sensitive to this and what you are finding is that the PID control is not setup for the behaviour of the wastegate, regardless of what you do with preload. You need a fully custom map where the PID control and N75 mapping are calibrated for your actuator, or you need to go back to a standard K04 actuator

I don't understand why people fit them to a K04

[pudding]

I was also wondering why the WG, DV and LPFP were changed for aftermarket ones, for what is essentially just a K04 spec engine, no offense.   These are items you would only consider for hybrid / Garrett / EFR turbo conversions......and even then, only when the original parts are deemed inadequate for the pressures involved.

I think the issue here is over complication.   Neither the WG, DV or LPFP are required and you also have a boost gauge that is inaccurate, and it's all sending you round in circles with the data.

If it were me, I would be refitting the standard DV, standard WG with factory pre-load, standard LPFP and a regular K04 tune from APR or Revo.....and bin the gauges!  Taking a step back to basics is the best tactic when you can't see the wood for the trees.

Nobody in the UK touches any of that stuff.   We do the usual bolt-ons and get a tune, job done 

[ROH ECHT]

I was also wondering why the WG, DV and LPFP were changed for aftermarket ones, for what is essentially just a K04 spec engine, no offense.

I think the issue here is over complication.   Neither the WG, DV or LPFP are required and you also have a boost gauge that is inaccurate, and it's all sending you round in circles with the data.

The AWE-DV came with my K04 kit from AWE. The WG and LPFP were originally added when I ran the DriverMotorsport or DM custom tune for over two years. The DM tune was pretty much an e-tune....had to tune it back to stock and load his base tune he sent via email. I'd run data with vcds and email it and wait for a revised tune sent via email. I download it onto the program loader and run data again and email it to him. If it looked good we were done but if not he'd email another revision. I couldn't get the WG to hold the boost with no amount of added preload and why the Forge was installed. Then there was the fuel pressure target increase, the oem lpfp couldn't match the target pressures and so the added lpfp upgrade. It did 370 bhp and 335 lb*ft. My GIAC does 350 bhp and 363 lb*ft and outruns the DM tune in the 1/4 mi. in ET and trap.

For the DM open-loop tune it needed a 3 bar MAP sensor, boost target was 27-28 psi throughout the rev range...even though I ran the boost at 26 psi, high fuel pressure target = 143 bar, low pressure target = 5.5 bar. Never was happy with that tune or the tuner and switched back to GIAC. I do plan to go away from the Forge WG but will keep running the LPFP with torqbyte's PM3 because I may choose APR's TTE420 over a K04 next time. APR's TTE420 kit requires a 155 bar FPRV and LPFP upgrade. My lpfp and PM3 doesn't over pressurize. With the K04 and GIAC tune, it just runs at a lower duty cycle having more amps supplied by the PM3 to meet its target low pressure.

Its the actuator. Why have you changed it? These ECUs are incredibly sensitive to this and what you are finding is that the PID control is not setup for the behaviour of the wastegate, regardless of what you do with preload. You need a fully custom map where the PID control and N75 mapping are calibrated for your actuator, or you need to go back to a standard K04 actuator

I don't understand why people fit them to a K04

I added the Forge WG actuator and LPFP as stated above...out of necessity to run the DM K04+ tune. Have since switched back to GIAC and all has not been well regarding the WGA as you can see. I tossed the K04 actuator into the garbage back then and have to wait now until a new K04 is needed for an oem WG actuator. I believe also that it is the Forge WG paired with the GIAC tune. Right now it has near zero preload at just 1/2 turn added preload and boost is 21 psi peak and I will just drive it with the Forge WGA until I get a new K04 or TTE420.

Thanks to you both for checking in and for your responses....the WGA situation is getting old and I cannot wait for a new turbo to show up one day on my doorsteps. Cheers 

[ROH ECHT]

Also, today I tested my boost gauge with my MITYVAC. It was losing 1Hg/8 seconds. After checking the gauge I checked my DV  and it lost none. I am going to plug the Tee where the gauge is attached and recheck data.

[Dan_FR]

I wouldn't have even entertained changing all of that on a K04 when it simply isn't needed... but yeah sadly regardless of what you do with the pre-load it will not work with the actuator.

Surely you can find someone that can supply you with a standard K04 actuator? TTE maybe as they buy new genuine units and replace the actuators when making the TTE420/480

[ROH ECHT]

I wouldn't have even entertained changing all of that on a K04 when it simply isn't needed... but yeah sadly regardless of what you do with the pre-load it will not work with the actuator.

Surely you can find someone that can supply you with a standard K04 actuator? TTE maybe as they buy new genuine units and replace the actuators when making the TTE420/480

No, you're right. Again, I didn't initially need the WGA or LPFP upgrade with the GIAC tune. Was when I decided to try the DM tune and get 20 to 30 more advertised HP when those bits were needed to get where DM wanted it. I wish I never did it obviously. 
Thanks...and done, just messaged TTE. I know those are near impossible to get separately. Only, I really do not ever want to swap out a WGActuator again while the turbo is mounted because that was not a fun day. I will most likely just wait until I need another turbo and run it best I can until then.

[pudding]

I was also wondering why the WG, DV and LPFP were changed for aftermarket ones, for what is essentially just a K04 spec engine, no offense.

I think the issue here is over complication.   Neither the WG, DV or LPFP are required and you also have a boost gauge that is inaccurate, and it's all sending you round in circles with the data.

The AWE-DV came with my K04 kit from AWE. The WG and LPFP were originally added when I ran the DriverMotorsport or DM custom tune for over two years. The DM tune was pretty much an e-tune....had to tune it back to stock and load his base tune he sent via email. I'd run data with vcds and email it and wait for a revised tune sent via email. I download it onto the program loader and run data again and email it to him. If it looked good we were done but if not he'd email another revision. I couldn't get the WG to hold the boost with no amount of added preload and why the Forge was installed. Then there was the fuel pressure target increase, the oem lpfp couldn't match the target pressures and so the added lpfp upgrade. It did 370 bhp and 335 lb*ft. My GIAC does 350 bhp and 363 lb*ft and outruns the DM tune in the 1/4 mi. in ET and trap.

For the DM open-loop tune it needed a 3 bar MAP sensor, boost target was 27-28 psi throughout the rev range...even though I ran the boost at 26 psi, high fuel pressure target = 143 bar, low pressure target = 5.5 bar. Never was happy with that tune or the tuner and switched back to GIAC. I do plan to go away from the Forge WG but will keep running the LPFP with torqbyte's PM3 because I may choose APR's TTE420 over a K04 next time. APR's TTE420 kit requires a 155 bar FPRV and LPFP upgrade. My lpfp and PM3 doesn't over pressurize. With the K04 and GIAC tune, it just runs at a lower duty cycle having more amps supplied by the PM3 to meet its target low pressure.

Its the actuator. Why have you changed it? These ECUs are incredibly sensitive to this and what you are finding is that the PID control is not setup for the behaviour of the wastegate, regardless of what you do with preload. You need a fully custom map where the PID control and N75 mapping are calibrated for your actuator, or you need to go back to a standard K04 actuator

I don't understand why people fit them to a K04

I added the Forge WG actuator and LPFP as stated above...out of necessity to run the DM K04+ tune. Have since switched back to GIAC and all has not been well regarding the WGA as you can see. I tossed the K04 actuator into the garbage back then and have to wait now until a new K04 is needed for an oem WG actuator. I believe also that it is the Forge WG paired with the GIAC tune. Right now it has near zero preload at just 1/2 turn added preload and boost is 21 psi peak and I will just drive it with the Forge WGA until I get a new K04 or TTE420.

Thanks to you both for checking in and for your responses....the WGA situation is getting old and I cannot wait for a new turbo to show up one day on my doorsteps. Cheers 

OK, well I can see why you weren't happy with the DM configuration.  28 psi isn't a sensible amount of boost to pull out of a standard K04, and neither is trying to hold it through the entire rev range!   VAG wouldn't pay for a turbo that's built to sustain 2 bar boost all day long, but only run it at 0.9 bar (ED30) or 1.2 bar (S3). They pay for the bare minimum.  The factory 270 degree thrust bearings are under spec'd for that level of axial loading.   Revo's K04 2+ tune only requests 1.45 bar (21psi) which seems sensible to me, with an emphasis on reliability over peak numbers.

143bar rail pressure also seems excessive for a K04.  What kind of AFRs does your tune request?  I know a lot of tuners throw in a lot of 'arse covering' extra fuel, but really, a GDI turbo engine's sweet spot for power is 12.8 AFR, perhaps tapering down to 12.5 for a little safety margin.   TFSIs certainly don't need the black fog being kicked out of the tailpipe I see so often these days.

I have no idea why AWE are supplying DVs in their kit either as it's simply not required, and something isn't right with your turbo if the standard WG can't cope.  Have you physically checked it lately?   Drop the downpipe and see if the penny valve spins.  With the correct preload, you shouldn't be able to turn it by hand. Also look for cracks in the housing around the valve, chipped turbine wheel etc etc.

I think this would be a good opportunity to start over if you are considering a TTE420.   Yes I imagine APR's TTE420 tune would specify THEIR lift pump kit, but a TTRS OEM drop in would suffice.   Be mindful of tuners upselling you stuff you don't need.  And you also don't need to run it flat out either.  Save some money on hardware and fuel by running it to 380 instead of 420+.    If you have 380hp, and additional +40 won't blow your skirt up......but it may well blow your pistons and your wallet!

[ROH ECHT]

Having to rebuild the engine at 120k miles is why I left the DM tune and went back to mu=y GIAC tuning. I had a piston ring pinched in its groove in the #4 cylinder. My valve stem guides and seals were also shot. All of this coming shortly after running the DM tune prompted me to be happy with what I had with GIAC. DM is no longer in existence and I for one sadly and regrettably know why. Right, 28 psi was too much and why I went for less because if I load boosted from low rpm's...the gauge would initially peak at 30 psi when he finished tuning adjustments with the added WGA. This was when I reduced preload in the Forge and I got boost peak down to 26. Current tune AFR specified is 12.35 to 12.5 throughout the rev range of 4k to redline.

Alright, boost bouncing about was fixed. My NSP boost gauge comes with nylon tubing but is inserted into rubber hose for the connections at the gauge and the tee fitting on the mani. The connection of nylon tubing inserted into hose just before the intake mani tee didn't have any zip-ties on it. I ensured a good amount of the nylon tubing was inserted into the hose and added 2 ties and the  vac test and actual steadiness of the gauge reading proved this to be fixed. 

[pudding]

Oh no, that is some bad luck.   Unfortunately these engines do crack ring lands pretty easily when pushed too hard.  Obviously the factory ring gaps are set for standard cylinder pressures and heat ranges, plus a little headroom.  It's only a matter of time before too much pressure/heat will bind the top ring and crack the landing.  I admire your staying power though 

DriverMotorsports are no more?  They've still got a website running!   Your AFRs are pretty sensible then, which is good.   I've seen my Revo software request 11.5 AFR, which is ridiculous, and with embarrassing smog clouds behind me 

Have you considered running a digital gauge?  I don't like zip ties in engine compartments for many reasons, but you could take a signal from the MAP sensor.

[ROH ECHT]

Yeah, thanks. I've always planned on keeping this MK5 as long as I can keep its heart pumping.

Mine actually ended up being the second compression ring...not the first/top. Wasn't too bad for the repairs albeit too soon...the head rebuild_shaved slightly_added 0.030" exhaust spring shims_with new guides and seals, new #4 piston, new rings on all four, and new connecting rod bearings was just $2500usd including all of the labor.

Yeah, DM's pages are still up but nearly everyone says they receive no responses when they attempt to make contact.  They quit responding to me over two years ago.

I have 0 to 120 mph vids of both the GIAC and DM tunes on my page; https://www.youtube.com/user/zoomdis/videos

Curious, because the DM seemed quicker but it never could beat my GIAC 1/4 mi best of 12.8s @ 112 mph.

[Dan_FR]

All that boost and big torque makes a car feel quicker than it really is, which is why people love diesels and think they're fast, especialy remapped diesels.... They feel fast, but they're just not 

[pudding]

Maybe the GIAC map is just smoother.  Smooth is always faster than aggressive wheel spinning spikes.....but it just doesn't feel it on the butt dyno.

Ya, diesels make a lot more power than petrol low down which makes them feel thrusty, but they're a bit premature ejaculation really.  It's all over way too soon.

[ROH ECHT]

All that boost and big torque makes a car feel quicker than it really is, which is why people love diesels and think they're fast, especialy remapped diesels.... They feel fast, but they're just not 

Exactly...been happier with GIAC and 22 psi.

[ROH ECHT]

Maybe the GIAC map is just smoother.  Smooth is always faster than aggressive wheel spinning spikes.....but it just doesn't feel it on the butt dyno.

I agree...I never was comfortable with boost holding at 25+ psi throughout the rev range with that DM open-loop tune...obviously it was never beneficial as well.