This one is throwing me for a loop. Got the trans back together and installed after I replaced the input shaft/hub. Trans works great. Now the motor is doing weird things.

Seems to have an intermittant power loss on the upper end. Several times on the way home I would floor it and it feels like its' de-fueling....hard. Won't make boost over 18-20# and won't rev past 2K. Won't hold 70MPH on hills I used to burn up. Boost and speed both fall when going up a grade.

If I ease into the throttle, it'll run hard, then fall flat on a slight hill. Other times it'll pull hard until I mash the throttle, then it feels like its' de-fueling again. I did manage to hit 36# once on the way home, but it still won't hold boost.

Can't find any fuel leaks, intercooler piping/boots look fine, valet switch and fuel solenoid are both coming up.

The only thing I can possibly think of is I removed the quick connect on the fuel return line (near the starter) but I checked it and its' not leaking fuel.

Any ideas?

 

You may want try an adapter with an valve stem on one end and something that attaches to the turbo compressor inlet on the other end. Use that to pressure test the turbo, intercooler and charge air piping. My guess is that the AFC isn't seeing boost and therefore it's not fueling as hard. Just my guess tho... seeing as I'm overvalved.

brandon.

 

I have the same kind of probablem with my 24v. Only I can build more boost than that. I get to about 35 and then it starts to fall off, then comes back until higher boost levels then drops off again.

 

I just when out and checked the turbo.....I can move the shaft up and down with my fingers....

 

Ouch!!.. Dont do anything else with the truck until the black cloud over your head moves away

 

Looks like it's time for twins.

Oldsmokey, are you seeing any codes? It sounds kinda like the VP is going out.

 

I do have codes, I cant remember which ones but two of them were injection pump codes. I read some where that a loose pump wire can cause these two codes to be set (I did have a loose wire). Ive been driving with these codes for about 5k miles. I guess I should get the codes cleared and see if they come back. Also it falls on its face at 90 mph every time at wot, but not when I let off a little. It feels like someone is switching levels on the box. From 1 to 5.

 

If it's P0216, then get ready to replace the injection pump.

 

Thats not bad.......depending on how "much" movement there is. Its the front to back that you really don't want.

 

Talked to Harry @ Piers this morning.....shaft play is normal. So I got that going for me.

Leaning toward a fuel pressure problem at this point, just need time to go hook up the pressure gauge...

 

Finally ran the problem down.....

Lost ever more power today, wouldn't get out of it's own way. Turns out it was no coincidence I was down to 1/4 tank of fuel. Had three holes rubbed in the return line in the pick-up/sender unit in the tank. Fixed the fuel level sender while I was in there. Didn't quite put the unit back together right, and got stranded around the block. Another story, but I was able to walk home, get some tools, and fix it in about 1/2 hour.

Came home, dropped the tools off, and took it for a WOT test run. Still falling flat. Has to be the fuel pressure. So I Mickey Mouse some fittings together and get the gauge hooked up, fittings are leaking, but the fuel pressure seems fair.

Then it occurs to me.........valet switch in on.

So here I sit at 1 AM local time, after wrenching on it for ~ 7 hours.
Runs like it should now, I'm back up to +1200EGT and 43 lbs of boost.

Thanks to all of y'all who weighed in on this......

 

Yea, now one else has ever made a mistake........it's called learning!

Jim

 

Conrad:
First sit down relax and let out a good yell or cry then grab one of your favorite beverages and relax. It's good to go, you fixed it and a lesson learned. Good news that all is OK now.
Bruce

 

Bruce, Jim

Thanks guys. I feel better now.

Turns out it was the lift pump anyhow.....can't figure out how I got 43lbs of boost with 0 psi fuel pressure