Oh yeah, she accelerates & runs better w/ the MAP unplugged! I tried 2 MAP sensors. I think seeing as it runs off manifold pressure & not fuel pressure, it's exasberrating the problem by further leaning the fuel out. I think. The only things that have seemed to help are new IDM, shimming the FPR & unplugging the MAP.

 

If your maintaining anything above 30psi, fuel pressure is not your issue.

These trucks will not cross the road without the turbo, the MAP sensor controls all the fueling maps, without that it will never run right.

To test fuel pressure rather easy find the fuel bowl drain valve, put a clamp where it goes from the drain valve to the metal tube that runs down the motor (this is so it does not blow off when you do the next part...) then hook some 3/8" fuel line to the end of the drain valve and connect that to a pressure gauge.

Once this is done, start the truck and open the drain valve. You will then see the pressure the pump is putting out. As I said, anything above 30 psi will not really cause any performance issues.

Anything between 50-70 is completely normal.

HPO is where its at, but I would check all your boots for leaks, and your up pipes as I showed above.

 

If you replaced your IDM without IDM codes then you did it for no reason. They don't wear out, they work, or they don't.

Ya really just have to get it on a scanner. Check your HPO and Duty cycle. Run a buzz test and a cylinder contribution test as well...

 

I did scan it also after replacing the injector sleeves. It gave IDM & TPS faults. After I put a new IDM in it shows no fault codes so I started unplugging/plugging things in as a process of elimination. We're more of a tires/brakes/align shop so the diesel troubleshooting is new.

 

I'll plug the MAP back in but trust me, it boggled the other mechanic & myself that it ran better unplugged. I've tried to 'test' & clean all the other sensors involved. Ran diesel kleen through her too. I'll plug the scan tool back in & check the cycles. Buzz test & everything else were good. That's exactly the advice I was hoping for. One guy tells me turbo, my guy says fuel & I'm dreading HPOP.

 

sounds like the turbo to me but im not an expert

 

I really do hope it's a turbo. Justifies me upgrading it at the same time! Hopefully today I'll get to drive it w/ the scanner hooked up & rule out the fuel & HPOP. Will update soon. Thanks everyone for the input.

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HPOP tested 500psi @ idle & 3000psi @ WOT

Fuel pressure is good at the bowl

Made a fitting to pressurize the intake & check for leaks in my tubes.

Buying boost gauge today.

 

This is a total shot in the dark but it sounds a little like what my 97 was doing when the EBPV got stuck closed. It couldn't get out of it's own way but didn't throw any codes. It's pretty simple to check so it's worth looking at before you go replacing stuff.

 

Tried cleaning out the tube-nothing. Un-plugged the sensor @the pedestal-nothing. Should it run better or worse un-plugged? Think I'm getting ahead of myself though. Need to check BOOST to rule out the turbo, which I had thought was done but was wrong.

 

Ok, heres my updates.
Pressurized the intake & no leaks in the tubes.
Fuel pressure @ the bowl while powerbraking is 65psi
Straight piped the exhaust (in case it was plugged) & while it made a noticable difference still feels underpowered.
Cleaned the EBV sensor & tube & tried unplugging it.
HPOP idles @ 475-500psi & about 2900-3000 @ WOT.
The turbo impeller spins freely & no play.
I could only get about 10psi boost @ WOT!
Only code I got was 1266 low to high short cyl 6.
After straightpiping I can hear the turbo trying to boost.
Once again, the damn thing runs BETTER when I unplug the MAP even w/ a different one?
Does this seem like a turbo issue?
I still need to check the donuts for leaks but I hate to replace a turbo & have it be an electrical/sensor issue?