im new to this forum but i got some questions bout my truck, one day i was drivin down the road and i just noticed that i was startin to lose my top end power, and now it has no top end. it doesn't smoke at all anymore and it only boosts to about 11 or 12 pounds tops, when it used to push around 40. It still runs great, just no power. I also noticed a fuel leak just a day or so ago, so could that be part of the reason to? I've talked to a few people, and some have said injection pump is going bad, and others have said its my turbo. any opinions or anything would help a ton.

 

Fuel/air= Power less fuel is less power i would fix the leak and go from there plus diesel is a lotta green these days, why waste it?

Chris

 

I assume you are working on a 97 12V? Fill out your signature with the specifics of your truck.

First, I would make real sure your fuel filter and prefilter are up to snuff. Then I would check your fuel pressure at the overflow valve banjo bolt, could be a weak lift pump or bad overflow valve.

The P7100 Injection pump is awful bulletproof, so that would be the last place I would suspect.

 

ya i changed the fuel filter just to check and it did nothing, i installed a holley blue pusher pump on it too and that didn't do anything either, so i dunno if the pusher pump would help, or if the lift pump went out it would still restrict the flow even though there is the extra pump?

 

No, it shouldn't restrict anything, so long as your pre-filter is also clean.

The way pressure is regulated is via. the overflow valve though, located on the output flow of the IP. If it is bad or the spring is weak, you can push all kinds of fuel through it and never build the correct pressure.

With the engine off, and using a broomstick, etc, when you pump the lift pump manual prime, do you hear a high pitched whine from the IP area? I don't know if the pitch would change much between a good overflow valve and a bad one, but I would suspect it might.

 

Find the fuel return hose [ not line ] & pinch a little at a time , with a fuel pressure gage attached , idle should be about 26-28 lbs , high RPM 1500-1600 , should be about 36 lbs , if not , then when pinching return line the pressure get to spec. then you know the overflow valve is ready to replace .

 

k i just fixed my fuel lines i replaced them from my auxiliary pump forward both supply and return. no more leak, but no change.
i also did a turbo swap but that did nothing either, i didn't really suspect it would though.
i haven't checked the overflow valve yet, is there a way to check it without using a fuel pressure gauge?

 

I think you can clamp the ruturn line then let it run for about few minutes. let it sit for a few hours overnight is better and start it if it starts fine then its the overflow valve. Im pretty sure that is the way to check some one will chime in and help me out thou im sure of it.

Chris

 

If you do not test things then you will only fix problems by luck , after so many parts , pinching the return without a gauge may do damage , since you can not see how much pressure your making as you pinch the return , so you have already put in parts that were not the problem [ no change ] .
The shortest [ cheapest ] way to fix anything is to test [ verify ] what is bad , then replace & test again to confirm the fix .

 

i fixed my truck today i'm pretty stoked about it, but it ended up just bein the fuel shut off solenoid. the bolts that hold it to the afc housing stripped out to where it wasn't held in place when the truck started so it wasn't pulling the fuel lever up all the way

 

so u didn't even have to replace the selenoid, just the bolts? nice, glad u got it worked out.