Mk3 Tdi 110 Power Loss

[alix]

Could'nt find anything specific on this...This morning I seemed to be losing acceleration mid-journey, i's as though the turbo suddenly is'nt kicking in and it drives and sounds like a non-turbo diesel. i.e no surge of power when I put my foot down but there is no smoke or any other signs of a problem. I f I stop, turn off ignition and start up again it seems ok again, engine management problem? Any opinions appreciated.

 

[allh2k]

Limp Mode

Could be one of serveral sensors or the turbo.

Should be an alert or meaage on the ECU as to why it happened (need a lead and VAG.COM to read them)

I was over taking when i went into limp mode so had to turn on and off while driving on the wrong side of the road lol!

Mine only does it when I am driving to fast usually a gear change from 3 -4 or 4 - 5 at 3500rpm+

stops me driving fast...

 

[alix]

Cheers mate, Saw this on original review by honest john

"Power loss on TDI 90s and 110s over 3,000rpm can be cured by replacing a thin hose that runs from the exhaust, near the turbo, to the ECU" Ever heard of this?

can't post url...annoying

 

[alix]

http://www.honestjohn.co.uk/carbycar/index.htm?md=359

 

[A.m.C_Ibiza1]

ive heard sticky turbo vanes cause limp mode! sticks and makes it overboost (hard acceleration!) and kicks ECU into limp mode! u have VAG COM??

 

[Muttley]

The Honest John answer is only good for early TDI 90's

------------------------

That's running from the *Inlet* near the turbo, not the exhaust. Even though Honest John says the exhaust, he's wrong.

This is good advice, but only valid for early TDI 90's (AHU, 1Z and the like - Mk2 Ibiza's etc) - the hose is taking manifold pressure to the Manifold Air Pressure sensor, which on these engines is integrated into the ECU. Later engines (including everything bigger than 90bhp, I think) has the MAP sensor in the manifold, together with the Manifold air temperature sensor.


You need a VAG-com analysis to narrow down what's causing you to go into limp mode. The usual suspects are the variable-geometry guide vanes in the turbine section of the turbo getting sooty and sticking, or the EGR valve clogging up the inlet manifold and sticking partly open.

 

[alix]

Thanks guys, what's the deal with vag.com and connections etc? Can it be 'sourced' on the net?

 

[malcpw]

You can buy a code reader like this

As newbie Forum won't let me post URL try ebay search for vag code reader or DTC reader.

You get a code book with it and it will tell you if you have boost deviation or other issues. They are not as good as vagcom but are stand alone and easy to use. They can also clear codes which means you can narrow down circumstances that cause problem to occur.

For VNT turboed engines a split or leaking VACUUM pipes usually means turbo won't boost. But limp mode is usually result of sticking vanes on these engines. Stripped, cleaned and rebuilt mine last week- resolved problem.

If you have non VNT turbo a split PRESSURE feed to the turbo means turbo will over boost forcing limp mode. In effect the turbo goes unregulated and without limp mode engine would try to self destruct.

Hope this helps

Malcolm

 

[kirsti.c]

had this same problem for a good while, stuck it into the dealers and turned out to be the maf and wasn't expensive to replace. usually happened to me when i hit about 80mph so sounds the same.

 

[alix]

Thanks Guys advice much appreciated

 

[ryanp]

Sticking vanes caused by lugging the engine or a faulty MAF putting the car into smoke limit mode!

Ryan