toeneal

Earlier this afternoon I completed my ASP stage 3 install. Prior to putting the front end on, I performed a pressure test to 20 PSI and didn't detect any leaks. Once the car was back together I made sure to properly prime the turbos before starting the car. After starting, the car idled fine and came up to temperature. More coolant was added and everything seemed like it should. I let the car cool for about half an hour and then took a test drive. During the start of the test drive I only noticed 5 PSI of boost from the boost gauge. Thinking that maybe for some reason the car was running in valet mode, I turned the car off and checked the programming. It indicated that the 93 file was in use, so I switched to valet mode, in case the file names were reversed. During the next test drive the boost gauge indicated 0 PSI. I switched back to the 93 program and test drove yet again. This time I only saw 0 PSI. I VAGed the car and saw a n75 code. After checking the n75 valve I found that one of the pins within the connector had bent down and was not making contact. I bent the pin back to the proper location, reconnected, and cleared the code. The next test drive was the same with 0 PSI. I then logged 115 and observed that the car is not requesting boost. The actual shows slight fluctuations. This time their were no longer any n75 codes.

Is it possible that the n75 is fubar? Or is there something else I might be missing?

Any help is appreciated.

Thanks

Mark@AutoSpeed

if so, try to remedy the electrical connector or replace the N75.

Give us a call monday if you need help. Good Luck

toeneal

Thanks Mark. I'll try that tomorrow.

toeneal

See below for the log from 115.

Engine Speed Engine Load Boost Pressure Boost Pressure
(G28) (specified) (actual) TIME
/min % mbar mbar STAMP
1400 17.3 1000 990
1400 17.3 1000 990
1440 30.1 1000 990
1520 35.3 1000 980
1760 51.9 1000 980
2120 58.6 1000 990
2480 58.6 1000 1020
2880 58.6 1000 1060
3280 60.2 1000 1110
3680 60.2 1000 1160
4080 60.2 1000 1200
4440 59.4 1000 1230
4800 59.4 1000 1240
5160 59.4 1000 1250
5520 57.9 1000 1270

The only code I am seeing is from the n75.

1 Fault Found:

17956 - Boost Pressure Regulation Valve (N75): Open Circuit
P1548 - 35-00 - -

Readiness: 0010 0100


What else could cause an issue like this?

-SlowSilverTIPJason-

and clear the codes does the open circuit code come back? If so you may have a bad connector or the coil inside the N75 may be bad. Use a DMM to see if there is any resistance on the 2 contacts on the N75. If there is, you either have a bad connector on one end (ECU or N75) or you have a cut wire.

I'd plug everything back in, remove the battery cable for a little bit then hook it back up. Clear the battery code then see if it's requesting boost or has any codes back from N75 open circuit.

S4lorn

said with it unplugged. It might not show requested boost(I don't think it will but I could be wrong) but you should make boost up to spring pressure.

toeneal

Now that I think about it, I don't think I would see any requested without the N75 connected, as you and Jason have mentioned. The amount of work I've done on the car this weekend has me both physically and mentally drained. I'll check the N75 with a DMM later today or tomorrow.

Thanks for the input.

AudiSportB5S4

Did you install the turboz ?! lol. that sucks, try another ECU possibly?

S4lorn

when you go stage3 no matter what unless you have just replaced it.

That little guy can cause a lot of problems and they don't always just fail, but sometimes they start acting up either under or over boosting. Given that you had a broken connection I am pretty sure it is just shot.

You can get one for less than $75 through genuinevwaudiparts.com or other vendors on the site.

good luck- My gut feeling is that you are OK and just need to replace it.

jprice@CPS

Do you see vacuum on your boost gauge at idle? Where's your boost gauge tapped, and are you sure it's hooked up right and working?