boost problem

[david]

my rs2 boost fine when the car is cold,but as soon as the car warms up boost is cut to 0.4bar?
wonder if anyone of you have had this problem,and direct me to the right way.
i don't own a vagcom so cannot pullout any codes.
could it be down to a faulty temp sensor ?




any imput welcome

[UrS4boy]

my rs2 boost fine when the car is cold,but as soon as the car warms up boost is cut to 0.4bar? wonder if anyone of you have had this problem,and direct me to the right way. i don't own a vagcom so cannot pullout any codes.
could it be down to a faulty temp sensor ? any imput welcome

What boost are you getting when the engine is cold? 2.0 Bar (+?) absolute?

The 0.4 Bar = mechanical boost only, i.e. just from the wastegate spring. The ECU is not providing the N75 WGFV with a signal. It would be like the ECU not being connected to the engine, i.e. an issue with the hoses into/out of the moisture trap:

http://forums.quattroworld.com/s4s6/msgs/20401.phtml

I don't think it is a G62 engine coolant temp sensor issue but it could be. Here is some reading: http://forums.quattroworld.com/s4s6/msgs/20985.phtml

Here is some N75 WGFV info:

http://forums.quattroworld.com/s4s6/msgs/20987.phtml

As for the codes, I am not sure if the RS2 has a check engine light. If it does then you can blink the codes out:

http://forums.quattroworld.com/s4s6/msgs/90409.phtml

http://www.sjmautotechnik.com/trouble_shooting/ecuf20v.html#fcs4

[david]

ecu chipped to 1.9bar boost,and that what i normally get when engine is cold.

[UrS4boy]

ecu chipped to 1.9bar boost,and that what i normally get when engine is cold.

Okay, that is a nice healthy RS2+ level (27.5 psi) (my RS2'd AAN with MRC Stage 3 s/w is normally 26 psi max).

I would check the boost line from the intake manifold, through the moisture trap to the ECU, looking for splits or loose clamps, etc. that change when the engine gets warm (hot)

If you find nothing, then the G62 has to be suspect. You *can* test it:

From Bentley, the G62 (Engine Coolant Temperature (ECT)) sensor test procedure is as follows:

Allow the engine to cool to room temp (68F/20C)
Disconnect ECT sensor from harness connector
Switch multimeter to resistance range
Connect multimeter to terminals 1 and 2 of the ECT
Resistance must be 1500 to 3000 ohms

IF NO = replace ECT
IF YES = check wiring between sensor and ECM (ECU)

http://forums.quattroworld.com/s4s6/msgs/20985.phtml

[david]

thanks
will check and report back
cheers

[david]

[QUOTE=UrS4boy
i've finally found the problem.
i unplug the G62 today and drove the car until it got red hot,then gave it WOT.
the boost gauge gave reading of 1.9bar boost,did for about 30 minutes and car was still boosting without any problem.
so G62 was the couprit.
i somehow i knew it was the G62,after discussion with urs4boy.
i actually ordered one a couple of days ago.
BIG THANKS TO URS4BOY FOR PROVIDING SO MUCH INFO.TOP MAN.