we learn from failures more than success sometimes.

[Theiceman]

and so .....

My son was struggling with a P0299 underboost code as some of you guys may have noticed my posts in other threads. My thinking is the turbo is just worn out after 320 k km but i thought i would throw a few parts at it .

i dont have a lot of time with the car but he left it with me and i put in a N75 and a diverter valve. Hell of a time with this as all bolts were literally frozen and corroded in place after many salty winters . .

i got them out eventually and bought some fuel hose clams to replace the one time use otiker clamps Audi uses..

very frustrating experience but i got it done.. very annoying thing was i could not get the n75 to click in place.. i got SKP maybe ( Chinese) and the connector just wouldn't click .. so i begrudgingly tie wrapped it.


took it for a test run and holy crap i killed the car .. couldn't get it about 3500 rpm .. and that was floored .. no check engine light , the car just couldn't go ...

brought it back home and pulled out vcds ... and pulled codes ... suction pump stuck P0087 and wastegate control failure N75

cycled the turbo bypass valve ( diverter) and happily heard it clicking away ...

cycled the wastegate controlled (n75) and heard nothing ...

crawled under .. cut the tie wrap pulled the harness down and plugged in my old N75 and click click ... worked ..

damn Chinese parts .. so i started pulling it all apart again ... when i got the N75 out i realized what had happened .. while fastening the boost line to the lower steel connector on the N75 the screw went through the clamp and just barely was hitting the electrical connector.. so when i tried to slide on the connector it wont click because it was hitting the screw and not seating... impossible to see from under the car that it wasn't all the way on and the screw was in behind so couldn't see that either..

once i reconfigured it a little the connector went on .. ironically i still couldn't get it to click and had to use channel locks on it to finally hear the click.

boost was back .. so there you go ,, be careful with those clamps ...

also odd i thought was the suction pump stuck code .. which went away as soon as i fixed N75 and reset everything.

[Jayz691]

Why would you even buy an SKP(cheapest aftermarket) n75, when an OE pierburg is cheap? Glad it worked, curious to what that cheap one test at(ohms). I had cheap one that were way off if the 25(ish)ohms when brand new. Pierburg was 24.7ohms).

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[Theiceman]

in Canada some parts are a lot more expensive .. many places don't even have pierberg. i just got what i got for a 320K car.

all you are really doing is firing a solenoid .. not sure what the difference in resistance would makes, unfortunately i didnt check it as it might have been good to know.

[Jayz691]

in Canada some parts are a lot more expensive .. many places don't even have pierberg. i just got what i got for a 320K car.

all you are really doing is firing a solenoid .. not sure what the difference in resistance would makes, unfortunately i didnt check it as it might have been good to know.

Well, for lots of sensors and solenoids on the car, thats how you test them. There's "spec" for resistance. So can't explain why, I'm not an electrical engineer. But id say it matters..
But long as it works I guess, right?.

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[Brenton159]

If you have the resources (workshp manual etc) to diagnose/check parts it can save extra work checking new parts prior to fitting
quick check prior to fitting can save hours of work if your unlucky enough to get a faulty new part

[Jay-Bee]

in Canada some parts are a lot more expensive .. many places don't even have pierberg. i just got what i got for a 320K car.

all you are really doing is firing a solenoid .. not sure what the difference in resistance would makes, unfortunately i didnt check it as it might have been good to know.

Napa has OE Pierburg for like 65 bucks, Part# ALT 9167

Tons of stock in Ontario, most counter sales won't find it properly but i know the NAPA/Altrom warehousing inside out.

[Theiceman]

already have it and its in .. oh well maybe next time if it fails..