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Friggin' Boost Again...

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
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, and then bounced up and down. 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. :iono:

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

xSabretoothx

Fast w/ training wheels
Location
Raleigh, NC
Car(s)
2008 GTI
Do you think its possible that your clutch could be slipping?
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
No, I don't believe it could be. RPM's do not rise...it is just boost dropping off quicker and more than normal. Just like it did, but not as bad as, before I replaced the N75 less than a year ago. 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.
 
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ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
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. Will report soon...
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
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
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
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.
 

GIACUser

Master Wallet Mechanic
Location
USA
Car(s)
MK 6 GolfR
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.

So if the complaint is that you see your boost drooping lower than expected as you move to redline, then start increasing wastegate pre-load. If that isn't sufficient you can buy a spring kit and for the Forge unit and consider going to the next stronger spring.
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
You think the blue spring is necessary? I have the set. Yellow is installed and I have been thinking I will try the blue but with minimal preload. This will likely hold the WG shut and increase boost, but when will it open is my concern. The blue spring is rated by Forge; "Blue - 14-18 PSI", which should be for double the spring rate to equal peak boost, but I've seen the blue again rated by Forge for 23 psi to 30 psi.

Then there's the whole thing; why did my fuel target pressure finally go above 110 bar when I removed all WG preload a few months ago per GIAC's request? I adjusted to zero preload, boost goes only to 20.5 psi, but finally fuel rail pressure target goes above 110 bar to 125 bar? Does the GIAC K04 HO tune hate this Forge WG Actuator and boost exceeding 21 psi that much?

The fuel target has been just 110 bar since reloading the GIAC tune over two years ago...the boost dropping just began last week. Why does it now need more spring rate? Just a year ago boost was peaking at 25 psi tapering to 21 psi before I reduced preload just months ago to peak boost at 22.5 psi tapering to 18.5 psi. Has to be something else this new boost issue, right? I think I may be wanting the two to be related so I finally solve the fueling issue of just a 110 bar target, loss of mpg, and a LTFT of 6.6%. It is getting old this having the weird issues no one else has. Others run the Forge K04 actuator, GIAC tune, and catless. What causes my low target? The boost thing I can correct.

Perhaps I need a vid because the boost drops off rather sharply after it peaks rather than dropping lower than expected as it moves towards redline. I'll get a vid tomorrow. Preload is just 0.5mm(1/2 added turns) so boost should only peak at 21 psi. Once today I saw it drop sharply to 10 psi after peaking. Data earlier today showed WGDC dropping to near 0%. Never saw this before.
 
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tedted

Newbie
Location
CA
whats the best method to adjust the wg nut?

sometimes I think I experience what your talking about. Rarely I can spike and hold up to 25lbs, but most times I ill spike the 25 and it'll go down to 22lbs and hold. BUT sometimes, it'll hold the 22lbs then spike drop down to 15-17lbs for 2-3 seconds then builds right back up to hold. not sure if my fueling drops with it so ill have to dig for my logs.
 

clockwise33

New York Giants Fanatic
Location
NJ
It doesn't look to me like you need more WG preload. The ECM is doing everything it can to pull boost out of the midrange, meaning actual boost is overshooting requested.

Follow the boost/fueling diagnosis guide from APR for the full picture:

Item # Vag-Com
Block # Description
*Not Applicable to EA888 TSI/TFSI Engines.
1 001-1 Engine Speed
2 014-3 Misfire Sum
3 031-1 Lambda, Current Value
4 054-3 Accelerator Pedal Position
5 054-4 Throttle Plate Angle
6 101-3 Injection Timing (Median)
7* 103-1* Current Fuel Pressure*
8 114-4 N75 Duty Cycle
9 115-3 Boost Pressure (Specified)
10 115-4 Boost Pressure (Actual)
11 230-1 Rail Pressure - Specified
12 230-2 Rail Pressure - Actual
 

GIACUser

Master Wallet Mechanic
Location
USA
Car(s)
MK 6 GolfR
You think the blue spring is necessary? I have the set. Yellow is installed and I have been thinking I will try the blue but with minimal preload. This will likely hold the WG shut and increase boost, but when will it open is my concern. The blue spring is rated by Forge; "Blue - 14-18 PSI", which should be for double the spring rate to equal peak boost, but I've seen the blue again rated by Forge for 23 psi to 30 psi.

Then there's the whole thing; why did my fuel target pressure finally go above 110 bar when I removed all WG preload a few months ago per GIAC's request? I adjusted to zero preload, boost goes only to 20.5 psi, but finally fuel rail pressure target goes above 110 bar to 125 bar? Does the GIAC K04 HO tune hate this Forge WG Actuator and boost exceeding 21 psi that much?

The fuel target has been just 110 bar since reloading the GIAC tune over two years ago...the boost dropping just began last week. Why does it now need more spring rate? Just a year ago boost was peaking at 25 psi tapering to 21 psi before I reduced preload just months ago to peak boost at 22.5 psi tapering to 18.5 psi. Has to be something else this new boost issue, right? I think I may be wanting the two to be related so I finally solve the fueling issue of just a 110 bar target, loss of mpg, and a LTFT of 6.6%. It is getting old this having the weird issues no one else has. Others run the Forge K04 actuator, GIAC tune, and catless. What causes my low target? The boost thing I can correct.

Perhaps I need a vid because the boost drops off rather sharply after it peaks rather than dropping lower than expected as it moves towards redline. I'll get a vid tomorrow. Preload is just 0.5mm(1/2 added turns) so boost should only peak at 21 psi. Once today I saw it drop sharply to 10 psi after peaking. Data earlier today showed WGDC dropping to near 0%. Never saw this before.

I would just try it. Simple and quick way to eliminate that possibility. Having said that, my opinion is that running with a new stock wastegate would be what I would try next since that is what your tune is based on and you know that has worked for you.
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
whats the best method to adjust the wg nut?

sometimes I think I experience what your talking about. Rarely I can spike and hold up to 25lbs, but most times I ill spike the 25 and it'll go down to 22lbs and hold. BUT sometimes, it'll hold the 22lbs then spike drop down to 15-17lbs for 2-3 seconds then builds right back up to hold. not sure if my fueling drops with it so ill have to dig for my logs.
I almost made a vid of my adjustment yesterday. Probably will make a vid soon to add to my youtube channel.

What I did yesterday was loosen both nuts away from the WG-linkage...push the linkage towards the actuator (passenger side) so that the WG is closed...turn the inner nut (the one between the actuator diaphragm and linkage) up to the linkage just to when it makes contact and back it off a selected number of turns (just 1/2 turn yesterday) to add a tiny bit of preload. Then tighten the outer nut (one near the end of the rod) back so all is tight. Also, over a year ago, I bought a M6x1 coupling nut and cut it in half and removed my outer nut and replaced it with one-half of the cut coupling nut. This makes it easier to use a 10mm socket when loosening or tightening that outer nut...but eliminates the ability to use the retainer clip. I did so because you will find out that trying to wrench on that is not easy because of the angle of the linkage often hides most of the outer 10 mm nut.

Steps for you;
First remove the inner passenger side CV shield. Then remove the retainer clip over the two 10 mm nuts on each side of the WG linkage on the actuator rod. Clamp a small needle-nose vise grip onto the actuator rod nearest to the actuator diaphragm to nearly eliminate the rod from spinning. Loosen the 10 mm nut nearest the end of the actuator rod (nearer to the driver's side) however many number of turns you plan on for reducing preload. Tighten the other nut towards the linkage until tight. Reverse this if adding preload. When you select a number of turns...you just count the 6 sides/turn. You can also use a small wooden dowel to turn loosened nuts up until they are snug...makes it a bit easier. If you want and can wait...I will do a vid within a few days if you need it...just let me know. Otherwise I may take my time because I do not need to make another adjustment...but I can do a repeat of what I just did and vid it along with explanation added for adding or reducing preload. It only takes 10 or 15 minutes to do.
 
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ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
Today I took my MITYVAC out to test something. I looked at my recent data again because I could not recall seeing the boost bouncing reflected in the data and it was not. So I used it to test my boost gauge and AWE_DV diaphragm since they are both Tee'd into the intake vac on the same Tee. The boost gauge was loosing vac at 1 Hg/8 seconds but the DV held. Then I thought, if it leaks under vac, it may possibly lose more under pressure. I need to test further with metered constant pressure, but what I did next was use my bicycle tire pump to pressurize the boost gauge tube...I took pressure up to 20 psi and held it there as good as I could applying constant pressure to the pump handle...about every 3 or 4 seconds the pump piston would instantly drop about one inch in order to hold the 20 psi. I am going to get a plug to plug off the Tee connected to the gauge and run data again. I doubt replacing the leaky boost gauge is the fix-all. But it still needs to be fixed.
 
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ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
I would just try it. Simple and quick way to eliminate that possibility. Having said that, my opinion is that running with a new stock wastegate would be what I would try next since that is what your tune is based on and you know that has worked for you.
Simple and quick isn't as such as when it wasn't installed yet. I would need to go at it through the wheel well with the liner removed it seems. Looked at it today and doesn't look fun at all. But I do plan on shelving the Forge when it gets a new K04...for sure!
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
My NSP boost gauge nylon tubing was just inserted into the rubber vac hose at the intake mani-Tee and wasn't zip-tied. I pushed the tubing into the hose more and added two small zip-ties to it and now it is all fine. Beers!
 
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