Problem?

[stevieyid]

Right after my other thread got locked after going a bit off topic i am still having problems with my overboost protection cutting in now and then. I have changed thermostat, coils, wgfv and still i get overboost protection when i give it WOT from low rpm's. So any other suggections as to what this could be? I am going to do another boost leak test but i think that is fine. Im sure its temp related shall i change the POS and see if that cures it? Any suggestions? Thanks

[stevieyid]

Also forgot to say when overboost protection cuts in if u take the ecu fuse (the one with motor on) out for a few mins it is fine again so it must be throwing a code out am i right? Anyone with Vag Com round London or the south east? Cheers

[stevieyid]

Anyone?

[Graham]

I had the problem with the MAF connection being dirty, used contact cleaner then contact lubricant and cure the problem

[kwlw]

Right after my other thread got locked after going a bit off topic i am still having problems with my overboost protection cutting in now and then. I have changed thermostat, coils, wgfv and still i get overboost protection when i give it WOT from low rpm's. So any other suggections as to what this could be? I am going to do another boost leak test but i think that is fine. Im sure its temp related shall i change the POS and see if that cures it? Any suggestions? Thanks

I may sound silly enough, but check battery connectors are they tight enough. I've had one become loose yesterday, and the car behaved like kangaroo. You can drive normaly for a 10 miles, however if you push the throttle enough to make at least 0.5 bar, it cuts out, and no errors on ecu. It was quite a mystery to find this out . Was lucky enough not to fry ecu with such thing.

Sau

[stevieyid]

When u say it cut out do u mean it cuts out completely or it goes into overboost protection mode?

[kwlw]

I want to say that it felt totally the same like overboost cutout. That's all. First thing I've checked after I spotted such behaviour was famous turbo to wgfv pipe (2 times on 2 cars it was a cause), and was suprised, that it's ok . Then after hour I've found the battery.

Sau

[stevieyid]

Thanks mate i know the battery connection is not brilliant so that could well be the cause. Would the turbo to wgfv pipe show up on boost leak test? Also when i pull the ecu fuse out for a couple of mins it seems ok again but then it would come back.

[merlin's S4]

I seem to remember reading that the overboost protection can be brought on by a faulty altitude sensor, although I would definately check the POS and the wiring to the coils first! May also be worth looking at the multi function temp sender (MFTS) if it's definately heat related! Is your car running at the correct temp now you've done the thermostat?

[stevieyid]

It seems to happen after long journeys and after sitting in traffic. It is running at the right temp just below 90 now whih is good. Just had brand new coils fitted so that should not be a problem. Thanks for your help

[dan_b]

Altitude sensor can definintely cause these problems.
Steve if you can get over to Richmond I've got VAGCOM, welcome to come round and see if anything shows up.

[stevieyid]

Is altitude sensor an expensive job?

[newsh]

Is altitude sensor an expensive job?

If I remember right, you can fix it for free, need to do a search, I'm going out there to look at mine right now so will tell you if its difficult to get at.

[stevieyid]

Thanks Newsh keep me informed

[newsh]

Thanks Newsh keep me informed

Right, takes 2 mins to remove, passenger footwell, left side bottom of the A pillar, remove the black plastic trim (only one screw holding it on mine). Pull away the felt sound pad and you see a window in the A pillar, sensor is in there, remove the plug and undo the screw and remove the unit, don't drop the screw
Now we have to find the instructions how to measure it.