Earlier today I installed a AF/X crank pulley. I test drove it and everything seemed fine. About 3 hours after the install, I tired to rev my car but it wont go over 3,800 rpm. When i go WOT the rpms bounce really fast from 3,800 to about 3,600 rpm about 6 times per second. It seems to struggle as well. Another thing i noticed is that my boost gauge is reading a constantly at -5hgmm almost torwards 0, even if i go WOT or not, the needle just stays there w/o moving. I talked to some of my friends they they suggested that i need to advance the timing when i installed the pulley, others say something is wrong with the intake manifold (OBX). Any help is great.

thanks

what else did you do when you installed the udp. and the obx manifold is shit.

If you're running an OBX manifold, I'd pay special attention to the MAP sensor and insure it has been fitted to the manifold...and perhaps not just connected and dangling in the engine bay.



http://www.dsmregistry.com/detail.php?carid=1185

I installed the Underdrive pulley with new belts. The car was running fine till this happened

Could be a coincidence. I can't find a reason that the revolutions of the pulley affect the upper RPM's of your engine. I have seen them affect the idle for a little bit (until the ECU "learns" it). But you do at one point reach in the area of the map when doing the install (for the alt belt). Possibly knocked something off? Generally, this problem leans toward Map. :shrug

MB

Originally posted by xcasbonx
If you're running an OBX manifold, I'd pay special attention to the MAP sensor and insure it has been fitted to the manifold...and perhaps not just connected and dangling in the engine bay. http://www.dsmregistry.com/detail.php?carid=1185

x2, check that MAP sensor!!

Originally posted by grain
I dont know why I said this because I have never used an obx manifold. However, Mike says it is shit.

Agreed. I love mine more than the stocker. Just like I rambled on about in the Turby section. Dont talk bad about products you dont use.

thanks guys very much for the input, it was indeed the MAP sensor that was disconnected, but when i do cold starts it seems to want to go below 1000 rpm then shut down so i have to give it a couple of good revs to keep it going.

Give it a little time. Try to allow it to rev down so that the ECU can "learn" the new UDP. Oddly, this didn't happen with me at cold start with the UDP install. It happened when warm. It may be something else (intake leak, IAC etc.) but I would give it a litle time first to see if it is the UDP.
MB

If your TPS is not connected it will do the exact same thing.