Tdi No Power - Looks like a turbo/vacuum issue?

[goalieadam]

Hi,

Look for some advice on what I can troubleshoot on my own before I take the car to a specialist as already invested some money in the car since I bought it a month ago. I'm competent enough to change brakes, do a basic service etc but certainly not comfortable removing the turbo which I hope this may not be.

History on what I've done so far. Bought this 2007 Tdi CAB with 122k on the clock. Had a few owners and definitely a few cowboys owning it previously, though I got it fairly cheap and was expecting to have to invest a little in it but probably now going into the realms of more than I would have liked in this short period of time.

When I test drove, ran ok, no warning lights etc. I know it had the EGR blanked but the previous owner had reinstalled one. It had been mapped at some stage.

Took the car to my local garage for a full service, at that point he could see the DPF had been hacked and cleared out but not done in a good way. Very noticeable any reputable MOT place would fail it, no immediate requirement though as MOT till June. Couple of other things leaking exhaust, and rubber boots. Week or two later it started to run a bit rough, had issues with acceleration and power in 1st and 2nd but get going and get on the dual carriage way ran pretty well, slight vibration at 2k in each gear. With the DPF and the leaking exhaust decided to deal with them both at the same time, but as EGR fitted and not knowing about the map etc decided to go back to stock so took to a tuner I know, he applied his stage 1 and had the DPF restated. Also made sure the EGR was restated too.

Picked up the car this week with DPF fitted etc and 5 miles in went into limp mode - P0234 - Overboost. Took the car out this morning, similar problem but now P0299, underboost! Called my tuner and his has reverted back to a stock map, my thinking is got it all back to stock as much as I can. Still no power but on the journey home no codes (journey there I had to reset the P0299 4 times in less then 5 miles!) When I say no power it takes 2 miles to get from standstill to 60 and there is no acceleration, I don't have VCDS but do have a Vident 700 from a family member, I can see from that when I was driving home and a snapshot I took that boost pressure specified was 1428.00mbar Boost Pressure Actual 1009.80mbar

So definitely looks like a turbo issue but are there things I can take a look at with my limited skills before taking it to a turbo specialist to rule out things cheaply?

Thanks for your help

[Crasher]

Which engine code? Sounds like a V6? So the DPF and EGR are back on and it has a standard MAP?

[goalieadam]

Thanks for the response.

BPW? Its the 4 cylinder 2.0 Tdi

Correct. EGR and DPF back on and standard MAP. DPF is brand new, unsure of age/state of EGR atm but planning to take a look this weekend

[goalieadam]

Just to add as maybe relevant based on other posts I have read. I'm not getting any sort of smoke coming out the exhaust.

[Crasher]

What make is the DPF, B&M?

[goalieadam]

Bought online, RTG automotive. garage also fitted new exhaust temperature sensor. I have seen the no power issue previously before having the work done but no error codes and would sort it self in a higher gear. No its consistent

[philipharmes]

If you are getting under boost have you checked the turbo actuator for any vacuum leak.

Suck on the vacuum pipe & check the turbo boost control rod moves, also that it holds a good vacuum if you put your tongue over the end of the vacuum pipe.

If nothing wrong there check for any leaks in the air pressure pipes from turbo via the intercooler to the inlet.

[Crasher]

Looks like a B&M to me in the pictures on their site, I had SO much grief on a A6 Ultra with one of those.

[goalieadam]

So are you suggesting a brand new DPF could be causing the issue? Are there other things I can try to to rule out first? How could I prove/disprove the DPF without purchasing a new one?

I've tried to give as much background in the original post. I was seeing an intermittent issue since buying 2 months ago 1st/2nd not quite so flat but wouldn't rev freely but once I got going into higher gears it was ok. Put about 1500 miles on like that but after finding the DPF, being told about the EGR and the intermittent issue. As I didn't really know the state thought best option was to get back to "stock". Had it mapped with DPF and EGR reenabled (don't know if EGR had been reenabled previously but made sure in my request). on the drive home EML came on as expected as expecting a DPF and none installed and it went into limp mode. reset and didn't check code as assumed DPF. Into garage, DPF installed with new temp sensor drove back home got a P0234, reset drove ok. Next day driving limp mode again, P0299. Drive to get stock map applied 4 x P0299 totally flat. stock applied drove home totally flat, no limp mode, no codes.

I have ordered a vacuum tester to try above, not sure where that is yet but I'm sure goggle will help unless anyone can point me to a guide for my engine model?

[Crasher]

The B&M one we fitted went wrong in days and after the 3rd warranty replacement failed we decided to get the original repaired, a stripped EGT sensor thread... problem solved.