Boost problems, diagnosis help needed

[Aaronneal]

Hi,

I am trying to solve a problem with an AGU engine 1.8t with r-tech map.

In 3rd when accelerating at about 4000 rpm it seems all boost and power just cuts out, like the turbo stops. and generally the engine feels down on power throughout the rev range.

recently i had a new cambelt and they also replaced a split vacuum pipe between the inlet manifold and somewhere just in front of the block.

Before this, engine would pull like a train, very very strong.

I have checked for fault codes and it keeps throwing up 2 codes but not all the time, i clear them and then drive a bit and eventually come back:

00575 - Intake Manifold Pressure
11-10 - Control Limit Not Reached - Intermittent

and

00561 - Mixture Adaptation14-00 - Adaptation Limit (Add)

only other thing to mention is that when revved to 3k, I then let it idle, when this happens the lambda reaches -17% this seems v.high compared to what i have read, could i have a dodgy lambda sensor, or maf? maybe n75?

anyone have any ideas what i can do, i have a few logs from vag-com, I am not sure if i have logged the correct things. Can get new logs if it helps.

log 1 - hard drive (max i could do)
log 2 - idling lambda measurements

Kind Regards and thanks for any help in advance

Aaron

 

[Sandip]

Unplug the MAF and take it for a quick drive Looks like a dodgy MAF bud

 

[Aaronneal]

ok, well it will have to be tomorrow now, what am i looking out for with it unplugged? will it drive as it should ..... ish? what else could i try if thats not the cause?

 

[Sandip]

If your MAF is dead your car will drive much better (unplugged) than it does at the moment. I'd have a good look around for boost leaks too. But to be honest i do think it's the MAF :icon_thumright:

 

[Aaronneal]

ok cheers mate, will let you know my findings tomorrow, are they prone to going just like that? its just spooky how it was as soon as i got it back from the garage when they fixed a boost leak.

 

[Sandip]

Yeah, MAF's are quite sensitive

 

[Aaronneal]

right so i unplugged MAF and it didnt seem to make much difference, however when plugged back in after 10 Mi of driving it seemed to put a fair bit of power back in the car, but still doesnt feel quite right..

i logged with vag-com again, and noticed that the throttle body only ever says idle, part throttle,enrich and ovverun, is it supposed to say full throttle at all?

 

[Aaronneal]

oh and duty cycle never seems to reach 100% is something to do with the n75? only 98/99% is this a problem?

 

[eddieantifreeze]

Did you guys solve this issue?

I have a very similar problem, recently been mapped at R-tech. At about 5300rpm the boost dissapears.

I have changed the MAF and fitted forge 007p, neither of these things have solved the issue. Did a fault code scan this morning and the only code to come up was 00575 - Intake manifold pressure, sporadic - resulting in limit not reached.

Its a new MAF (bosch one) and it did not fix the issue, any other ideas?

Thanks