VW Passat 1.9 TDi

billsteersnose · 05-12-2006 12:40pm #1

Hello!

I was wondering if anyone could tell me if this is a serious problem or not.
As I'm driving along, I sometimes find that the car looses power. It's normally when I'm accelerating, the turbo will kick in for a while and then it seems to just die. If I switch the engine off and on again and then accelerate, I have the power back again... Has anyone had this before?

crosstownk · 05-12-2006 12:45pm

I assume that there are no fault lights on the dash. It could be a faulty air mass meter or maybe a boost control switch. But to be honest, the best thing to do is have a diagnosis carried out to pin-point the fault.

Kojak · 05-12-2006 1:14pm

Our Passat had the very same problem. You will have to bring it to a garage - the problem, AFAIK, is there is a valve in the air-intake for the Turbo which is malfunctioning (i.e. it closes when it should be open and vice versa) It is also an electronics issue where the "wiring" is sending the wrong signals to the turbo.

As crosstownk said, have it checked out.

billsteersnose · 05-12-2006 2:28pm

Ah, that's great. Thanks a million! I'll give the garage a ring and get them to check her out...

spooner_src · 05-12-2006 2:36pm

Hey, I am pretty sure its your MAF (mass airflow sensor) it sits just after the air box that houses the filter.

I have a tdi and wondered why the hell at motorway speeds I seemed to be going nowhere.

It wont show up on a VAG diagnostics cause it didnt for me.

A sure way to find out is to disconnect the cable leading into the MAF sensor...then drive for a little bit. Dont worry cause the engine management system will default to a standard mapping for the fuel intake etc. If there is a little more response then your MAF is cooked. Mine cost about 130 euro fitted and now the power is back.

crosstownk · 05-12-2006 2:55pm

spooner_src wrote:

It wont show up on a VAG diagnostics cause it didnt for me.

It does actually - but not as a fault if you interrogate fault memeory. There is a specific test on VAS5051 that needs to be done while driving which will indicate a fault in the Air Flow Meter.

homerjk · 05-12-2006 3:24pm

Hey Spooner, did you get this done in Dublin by any chance?
Ive been meaning to get this done but I keep putting it off, but now my NCT is coming I better get it done because I have heard it will make my emissions worse than they actually are...

Mr.Diagnostic · 05-12-2006 7:20pm

crosstownk wrote:

It does actually - but not as a fault if you interrogate fault memeory. There is a specific test on VAS5051 that needs to be done while driving which will indicate a fault in the Air Flow Meter.

Quite right. All too often people expect the scan tool to tell them what is the matter while the reality is it's the man holding the tool who must understand how to read all the available data.

murphaph · 05-12-2006 10:02pm

Yeah, I performed that diagnostic procedure myself to determine my MAF was dead. It involves sticking it in 3rd and putting your foot to the floor! You need to look at the RPM at a certain speed IIRC (it's been a few years since I did it) and it doesn't register as a fault. The problem is that the wire's resistance changes over time but it doesn't 'burn out' and go open circuit! I replaced my crappy Bosch sensor with one for the Merc CDI made by Pierburg. It's a perfect fit and means you don't need to buy the entire housing unit so less $$$$$$$$. It's still going strong today.

VW Passat 1.9 TDi

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