[wmfamily]

I've been working through the consistent low power on my Golf since the beginning of winter and its not getting appreciably better. I've done all the basics (filter changes, snow screen clean, and replaced bad turbo vac line). I think going to have to move on to replacing the rest of the vac lines and start looking into more serious measures. BTW, no codes in VAGCOM (almost wish there were).

Wish me luck.

John

 

[Seatman]

Does the power come back when you restart the engine or is it just lacking all the time? If you look through here you'll see headings for low power and limp mode.

welcometomyturbodies

http://www.myturbodiesel.com/1000q/a4/a4-ALH-TDI-engine-index.htm

 

[wmfamily]

The power is low pretty much all the time. Its OK up until about 2300-2500 RPM and then I might as well get out and push. I remember the days of flying up hills but that's gone. Also, I have yet to have it show any error codes.

Over the weekend I checked the IQ and it was at ~1.8. I fiddled with the adaption and brought it up to ~3.2. It runs a little better but not much.

I also checked the vacuum hoses and found the one that leads from the vacuum canister was bad. I plan to get a Mityvac to check the system and replace the hoses.

I looked into the intake and it didn't look too bad but that may get a cleaning after I check the vacuum system.

John

 

[chittychittybangbang]

Have you datalogged the MAF sensor?

 

[blackgolfdown]

Low Power, Turbo, P0234 issues

I've been working through the consistent low power on my Golf since the beginning of winter and its not getting appreciably better. I've done all the basics (filter changes, snow screen clean, and replaced bad turbo vac line). I think going to have to move on to replacing the rest of the vac lines and start looking into more serious measures. BTW, no codes in VAGCOM (almost wish there were).

Wish me luck.

John

I am on the same pathway except that I have an intermittent check engine P0234 turbo overboost code. It does not have the pep it should normally and will go into limp mode also when the light comes on. We are working our way through everything in these pages. So far replace vacuum tubing, MAF, wastegate actuator have been replaced. I am resisting replacing the turbo as my mechanic has recommended. I am going to try the "run it up a hill hard" recommendation and see what happens. I have also looked into but have not tried yet adjusting the waste gate actuator. Also considering the solenoid N75 replacement.

 

[wmfamily]

The MAF was replaced a couple months ago since it was VAGCOM showed it was a little dodgy.

 

[3J's]

I just went through TDI hell that you seem to be entering. Over the last year I have had to clean the intake, replaced the N75, replaced the VNT valve, replaced all the vacuum hoses, replaced the MAF and air filter twice. Just this afternoon I finished with the fuel filter thinking that was clogged. It was dirty, but not clogged. while my son slowly increased rpm's I stood there watching, thinking of a way to run the car into the river when I noticed when he took it to 2400rpm's just as it would start jugging out and blowing white smoke out of the air filter box and the end of the exhaust, the anti-shudder valve was only partially open.... when I held it all the way open the car ran GREAT! I unplugged the vacuum line, stuck a stick in the line and took it for a rip down the freeway; it ran better than it ever has! I put my foot in it and as my wife and I talked I looked down and was bumping up against 100mph, backed way off the throttle, and it ran smooth all the way home.... now I gotta see if the anti-shutter valve is vital... check the position of your anti-shutter valve when it starts chugging out. push it open by hand and see if the engine smooths out..

 

[Seatman]

The anti shudder valve is a useful thing if you get runaway from a blown turbo and I think it's supposed to make slowing down smoother or something like that.

 

[wmfamily]

Just for grins last night I used the VAGCOM to check see if the N75 was cycling (group 11). I set everything up and took a mirror and could see the VNT actuator moving about an inch as is cycled on a off.

The search continues...

 

[kickercoach]

The actuator must be calibrated......

Hey, just because the actuator is moving through full stroke, does not mean it is working properly.

It must be verified to begin movement at approximate 3 to 5 "HG and then complete the stroke at approximately 20" HG. This must be verified. Utilize your vacuum pump for this.

If it begins operation at less than 3"HG and reaches the stop at say 14" HG your boost may be higher than it should be. This assumes (assumes very bad word) that everything else associated with actuator operation is proper.

Check the pressures.

 

[wmfamily]

Well I finally got my Mityvac and connected it to the VNT actuator and everything looks good...at first. It started moving at ~3" hg and moved fine up the top end ~18" hg but would not hold it. You could hear it hissing as the vacuum leaked out (in?).

So I guess I have found my next problem to fix. At least I have another piece of useful information to work with.

Another odd thing...the other day I was driving home and was climbing a long, gradual hill and when I gave it the beans the power really dropped off. Actually started loosing speed and was dog slow the rest of the way home. Once I shut it off and restarted it was back to its "normal" powerless self. I'm suspecting it went into limp mode but there were no codes or CEL. Is that normal/possible?

John

 

[kickercoach]

10-4

Mine would not post any faults when falling into limp mode. Of course I did have a few faults to correct Before I got that far on mine.

A typical scanner will not show all of the faults. You need the VAG.com stuff.