gorms

Hello all,

I've been noticing sometimes the truck seems to be dragging a bit. I know there are a few issues, one I've been chasing/neglecting is low fuel pressure. I see no more then 22 psi usually, with a fresh filter and opening up the needle valve a bit on the gauge I can see it pulse up over 30. At idle and the needle valve barely open it only registers around 15 psi, on a very cheap gauge mind you.

I've already cleaned the tank/pickup screen which was basically plugged. Waiting for pre-filter screen and new fuel filter from geno's sometime this week to check that all out. Also have a new lift pump on the shelf if pressure is still low, as pressure doesn't increase much with the return line pinched off.

Anyhow, when it's low on power it almost seems like the AFC foot is staying back a bit or dragging slowly. I can still get well over 30 lbs boost not even full throttle, just doesn't seem to "snap" like it does when all is well, sorta hard to describe, seems to take more effort just cruising on the freeway empty.

Then yesterday I was driving it in nice cool weather and I jabbed the throttle a few times and it really felt like someone pulled a throttle stop off, just rips through the RPM range with little throttle. Seems like it should be running like this always, but over time it will start to drag again just like always. Had a fresh oil change at the time (under 400 miles) and fuel from my usual "good" supply.

I know there's a ton of variables, and I really need to get fuel supply up to snuff, but the annoying part is power/throttle response can change within a few days on the same fuel, same temps, etc. And even while being sluggish, still tows the camper just fine at over 7k. It never feels fast towing it anyway.

I'm running no fuel plate, stock 14* timing on a CA 180hp auto pump, stock sticks and turbo. AFC stock, wheel forward a bit and housing full forward, 230k miles so far, and still averaging 20mpg or better empty.

Thanks for any pointers.

gorms

Well had a good day of taking care of the truck. Started out with changing out pre-filter/filter, didn't really help fuel pressure though. It was actually starting to run rough at idle after changing them, pressure didn't change while pinching return line so I changed out the lift pump. In finishing that of course the starter wouldn't work, so grabbed a new one. Worked once then the 30a fuse for the solenoid kept blowing, wire was shorted somewhere......

BUT now pressure is up to 25-30psi, fires up much quicker and throttle response seems to be back and better then ever. 230k on the original so I'd be happy with another 200k before I do that again.

infidel

I've found if the tank filter is plugged that you really have to drop the tank and flush it out or the problem will be right back.

gorms

I did that about a month ago (maybe a bit longer) and it was plugged solid, cleaned the tank out as well. I've been filtering the fuel right at the filler neck now to find the "bad" stations, turns out to be a truck stop on the highway that I have to stop at once in a while that I find all sorts of crap in the screen I wrap around the nozzle.

So now the lines have been flushed, clean filters/pickup screen and clean tank, and cleaner fuel going in. Runs great now!


Actually I did notice, the fleetgaurd filter I got seemed to be smaller then the ones I get at Napa, everyone recommends them though. Just thought maybe a bigger filter (more element anyways) is better.