does anyone know if this will fix the PT/FB and the ECU not knowing how to adjust fuel? Run a T fitting between MBC and wastegate, connect stock boost solenoid into the T. Will the ECU now be able to adjust for the increased boost?

 

i dont understand the question is it the stock turbo and how many LBs of boost?

 

It's a stock turbo, boost set at 15psi. Orginally I had the manual boost control installed and the hose going to the stock boost solenoid plugged, per the instructions. Workes fine at WOT, but sometimes at partial throttle the car would start to stumble around 5000rpm. CEL was 1544, high EGT. I read somewhere online about putting a "T" between the MBC and wastegate and connecting the stock boost solenoid to the "T". You could set the boost with the MBC and ECU would now be able to adjust. If I understand the problem with MBC, since the stock boost solenoid isn't being used the ECU can't adjust rich/lean condions in closed loop which is partial throttle, but at WOT it's in open loop and the MBC works fine. I put the "t" inline between the MBC and wastegate and attached the stock solenoid hose. Have the boost set at 15psi, it's been one week, hit 15psi in every gear, no stumbling at any throttle position so far and no CEL. Car seems to run great, really spools up quicker. Is there any adverse effect from this that anyone knows of?

 

if you are getting a CEL for high EGT, that means it's pretty damn high. you will always run into PTFB issues in closed loop when running an MBC. your best bet is to put it back to stock before you damage your engine, if you haven't already.

 

Thanks for the reply. So even having the stock solenoid connected with the MBC won't help the ECU adjust properly in closed loop? Normally I don't run the car hard, 3-10psi and 5000-5500rpm shifts. Should I have thrown another CEl by now? Any way to tell if any damge has been done? Will the MBC be O.K. to use at the track, 1/4 mi.

 

Yeah, I've had the "t" in for about 300 mi. now and no problems at any throttle position and no CEL. Car definetly seems to react better, spools up just as quick as having just the MBC hooked up but none of the stumbling that I had encounterd. I wasn't sure what size "T" to use, think I put 5/32 in. This is just temperary until I get a UTEC, but so far so good. I am planning on installing a wideband for my air/fuel gauge. Let me know if you try this and your results.