Thread: boost issues...

Hey guys. been searching all night....i have a jwt 96lb program, msd ign. i have an eq length mani. holset hy35 (so it comes alive pretty quick), aem wideband, and so on.....
my issue is this.......i start the car, it runs and drives like a charm out of boost... my a/f is pretty rich at idle like 12.9 to sometime 10.8 but mostly 11.3's. It fluxuates slightly but more of a aic issue. Driving a/f are perfect for cruising like a stock sentra.
I go all the way to half throttle and it hits good. im at 10lbs. my fuel pressure is set to stock and it has a perfect 1:1 ratio in boost (i have an electronic gauge in car) but the gauge is at 10.0. i go over half throttle and all hell breaks loose.
My car will peg out and just break up and go no where. its like it stalls so bad. i seriously have to pedal it to make it go over half throttle.
Heres what ive done.
1. Ive checked my maf. part numbers fine. Reads good. Know for a fact its good....
2. Tps is fine checks out.
3. Pulled the spark plugs they look okay (which i think is due to just driving it normal.) gapped at 23
4. My buddie built the motor and is extremely knowledgable with sr's and triple checked all my timing and the cam timing is good.
5. No boost leaks.
It seems as if i have tried everything in my knowledge, and many more things as well to see what the issue is. Its driving me crazy! Anyone have any suggestions would be greatly appreciated. Anyone think it could be a coolant temp sensor issue????? My knock sensor is disconnected also but jwt said that was fine. Any suggestions are greatly appreciated. Just frustrated from spending a year and a half to run rich....

sounds like you have a fuel problem what do you have for a pump and how old is it ?

definitly sounds like a fuel pump issues, as the pump heats up it will start fouling out, then when you let the car sit, it will start up and run fine like nothing is wrong, this kinda sounds like your issue

Have you pressure tested the system? I know you said you don't have any boost leaks, but unless you've used a pressure tester there's no way to be 100% sure.

yah pressure tests good. If the fuel pump is fouled won't my pressure go crazy???

Not necessarily. What could happen is that the fuel pump cannot supply the volume required when the fuel pressure increases. As pressure increases, the volume of fuel also increases. You can run a higher fuel pressure and still get the same amount of flow, or possibly even less flow.

jwt deletes the knock sensor from their programs. Do you have access to a data logger. If so I would start by data logging and looking at the files to see what the problem is.

NO real access to a datalogger. And your saying that if I am pushing a certain psi in boost and it's fouled, I could be dumping more than that?? I have a Bosch 044 in the closet. Was just gonna wait. Right now it's an in tank 255 walboro

Well you know you are running richer than you should at idle. So either the wideband is off or you are really running that rich. I always use a safc-2 with a jwt ecu because I have had issues running too rich and too lean. My last program was trying to run 13:1 under boost. I had to dial in more fuel to fix the problem. I would do a wide open run then shut the motor down(no idling) pull the plugs and see if they are soaked. Nissan data scan is your friend when it comes to tracking problems like this.

I followed aem's instructions the best I could as far as the placement went and just put a new sensor in it from fouling my old one. I thought about going the safc route but am just concerned it won't take enough out of I am that ungodly rich. Keep it coming guys I really appreciate it! I taking it all into consideration. I'll see if I can access a way to datalog