1997 1.8tq 5spd. I have been on here and with my mechanic with this problem for over 5 weeks. Now (after new k03/dv/n75/ bosch ecm/and alot of vac leaks fixed) we have pinpointed the problem. The computer will not cycle(make pressure pulsate) the n75? When you bypass the n75 that car overboosts and bucks almost immediately (I'm guessing because of loss of vac causing dv to close) Normal? Before we replace that list of stuff we tried a new maf and didnt work and tomorrow my mechanic is gonna order another maf and try that...Anyone have a clue or came across this before?

 

What exactly is the fault code? Whats wrong with the car in the first place?

 

if hes a good mechanic he will have a copy of vag-com and you can hook it up and see if the maf is bad or not on the computer, without even having to open the hood.

well yea if you disconnect the n75, the turbo wastegate would not operate and the turbo would not ever stop making boost. this would increase manifold pressure causing the DV to stay shut, furthuring your problem.

you can replace the n75 with a manual boost controler and see if you have the same problems.

you said you replaced the n75? so it should be new and working... if its not getting signal from the ECU there would be a code stored saying that, which you would see in vagcom. could be a broken wire somewhere?

if your N75 not getting signal was the only problem and your mechanic replaced your turbo, DV, N75, MAF and ECU to get to this diagnosis, he is not a very good mechanic.

 

Never got any codes right from the start. The original problem was bucking or jerking while boosting. We can get the n75 to cycle through the vag test but the ecu wont do it on its own. So, the wastegate is getting constant pressure and therefore no turbo. Is it possible that my K&N filter is causing this?

 

The main thing is that we want to find the real fix to this problem... I know I could get an mbc and that would take care of it but it should not need that!

 

There has got to be sooooooooooomeone out there that has ran into my problem? Every damn circuit is good! All grounds perfect! What is goin on? I just want my front end to raise up and turbo kick in and put er in tha wind! Ahhhhhhhhhhhhhhhhhhh!

 

You've replaced everything that would be recomended to check. I'd just get a mbc and forget about it. NOT an ebay mbc.

 

That is so damn unsatisfying though!

 

$750+$40+$100+$350 ($1240)

vs

a $50 MBC

screw how i feel, i would rather satisfy my wallet. a difference of 5 bucks- fine. 50 vs more then 1000? il take 50 and forget about it

 

No offense bro but are you plugged in?! An mbc goes for $500 not $50!