When I had my RC2+ installed, my N75 was limiting the car to 10.5 lbs of boost. I didn't notice since that's almost stock. A few taps and some cleaning got it a little above that, but only when I swapped a new one on did I get the full 17 lbs requested.Hmmm, sounds like the intake manifold may be clogging up, dirty MAF connector and some hole in one of the intercooler pipes(very small hole, thus higher pressure makes it bleed).
N75's do or don't work...
I had the exact symptoms you have. After a lot of testing for pressure leaks and the turbo actuator it came down to the N75. Funny thing was the N75 tested good statically. I have no means to test it dynamically and that was the problem, it must operate at around 20 hz or so. Putting in a new N75 fixed the surging. I did not replace any vacuum hoses or anything else since they all tested fine. I did break the ECU MAP sensor nipple though.how easy/hard/expesive would it be to replace the boost control solenoid on my 1998 jetta? once i get above 2800-3000rpm at 1/2 to full throttle it starts pulsing/surging.
The diaphragm on old N75s gets stiff and cannot function properly. Replace it. ~$50 for a Pierburg generic one.
Do the vacuum lines from the N75 while you have it all apart.
What are the specs on these vacuum lines/place to buy them?Do the vacuum lines from the N75 while you have it all apart.