help?

[timmy]

I recently bought a 96 f-350, 2wd, 5spd and have been fumbling through several issues with tons of help and information from everyone here, thanks for that. Ok, heres where I'm at as of this morning. I have replaced the batteries, cables, valve cover gaskets, including wiring on both sides, cleaned fpr screen, installed fpr shim, fp gauge, and attempted to change MAP sensor. Fuel pressure is fairly consistant at 50-60psi, buzz test showed all good, MAP reads 30 while running, BP is at 20, ICP is 2480, IPR duty cycle is 35% while driving, EBPV unpluged, rod disconnected, and valve wired open. Truck runs ok, better than originally, until you reach 2100rpms than it starts missing like its starving for fuel, mypressure gauge is on the motor so I cant tell if im actually losing pressure. On a whim I unplugged the MAP sensor and the truck woke up and started running great without it, installed new MAP and right back to where I started, no power over 2100rpm, I dont understand this at all, truck is smoking white smoke with MAP plugged in, no CEL, cleared codes this morning before collecting this live data info and the only thing that came back was an irrelavant PO476, and a PO275 cyl 5 balance fault, now i'm not only totally confused but seriously concerned!! Any input would be greatly appreciated, I was hoping to be done banging my head against the wall when i got rid of my 6.0!

[whitepowerstroke444]

could have something to do with injectors or injector o rings when you unplug the map it wakes up the truck because it makes the computer guess how much boost is coming from the turbo so it gives it more fuel and since you shimmed and cleaned the regulator i wouild guess something with the injectors. i buzz tested mine and they all read back fine but i changed them cause i was having problems and they were shot when i took them out

[timmy]

Is there any way to be sure its an injector before I actually change it ? Next thing, I have no idea mileage on injectors but over 200,000 on motor, so I assume if one injector is bad then the rest aren't to far behind? Cant
really afford a whole set right now.

[joebob72209]

Don't know if this will be much help but did you inspect the length of your fuel return lines to make sure no kinks or debris blockage? Another possibility is have you checked your compression? A badly worn camshaft will restrict air entry during higher RPMs and work fine at lower rpms. Don't know if this helps at all just ideas. Also what kind of scanner are you using to get all this cool info?

[joebob72209]

Don't know if this will be much help but did you inspect the length of your fuel return lines to make sure no kinks or debris blockage? Another possibility is have you checked your compression? A badly worn camshaft will restrict air entry during higher RPMs and work fine at lower rpms. Don't know if this helps at all just ideas. Also what kind of scanner are you using to get all this cool info?

Sorry about that never mind. I didn't pay attention to the part where you said that it performs fine without the map sensor plugged in. Adding that bit of information in there i would say that you either have a wiring problem or an issue with your PCM or IDM or the communication between the two. Weird you are not getting any other codes though. Are you checking the DTCs / Continuous DTCs / And KOEO codes?