I've been diagnosing what I think is a low power, sluggish takeoff problem in my new 94 F-350 powerstroke. Yesterday I checked the fuel pressure and it was almost unreadable. I have a high dollar snap on fuel pressure gauge that has always given my great service and when I hooked it up to my truck the needle was jumping back and forth about 30 psi real fast. Never seen that before.

I even hooked it up to my tractor (also with mechanical fuel pump) just to see if I broke my gauge. It was a steady 50 psi at idle on that pump.

Is it normal to have the gauge needle jump so wildly on an early powerstroke is my question. It looked like 50 psi was about in the middle of the needle bounce range. It's a 49 state so I guess that is in spec but is it good enough really?

My whole FPR and filter housing is new as of 3 months ago from the ford dealer. The last owner had it replaced after he took it in complaining of low power. He said it didn't help. I got a good bit extra power after changing the oil the dealer put in it and using a whole 14 quarts. I switched to synthetic too. It has the recalled dipstick in it still. It's still nowhere near the power of my bone stock 97 powerstroke though.

The 97 will pull my horse trailer through the canyon near us without even downshifting. It's the E4OD trans in it. It stays right on 65 like it's nothing.
The other day when I tried it in the 94 I was in 3rd gear by the time I came over the top and only doing about 30mph. The 94 has the 5 speed ZF but there shouldn't be that much difference.

 

the bouncing needle is normal, nature of the beast.

does this truck still have a cat on it?

 

A fluid (Glycerin) filled gauge will give you a more accurate reading. Otherwise just do an averaging of the fluctuation.

Rog

 

i think he said its flucuatin 30 psi back and forth that seems odd

 

X2

Check the pressure at idle and WOT.

Bill

 

A fluid filled gauge would be nice. I have a hydraulic bale tensioner on my baler and I was never able to read that gauge before I put a fluid filled one on it.

When I push the accelerator the pressure does go up. It looked like to about 70 psi. Maybe I'm barking up the wrong tree trying to find out why it's feeling weaker than my other truck. It's almost no chance it's fuel pressure if it's normal for the needle to bounce. I'm about to junk the factory air filter on it and do a big donaldson filter on it like I did with the other truck and I'll see what happens. It could just be the difference between that big heavy clutch and the automatic for all I know too. It's just different and hard to explain.
It never had a cat on it as far as I can tell btw.

 

Does not sound to be fuel.
I would look into the boost side of things.
(turbo/mapp/ex leaks ect)

Bill

 

I did tighten all the air hose clamps a few days ago and looked at the compressor wheel. It looked brand new. I checked the air filter too. It's new. That's about the extent of what I've looked at on the air side.

This truck is pretty quiet out of the turbo compared to my 97. I remember when I did the air filter mod on that one the whine got a lot more noticeable but I can't say I noticed any more power.

Do any of you own 2 trucks like I do, one with an auto and one with a stick that can notice a difference in the way they drive and pull hills?

My 97 could be a fluke too. Another 97 F-350 dually I work on a lot seems real low on power compared to my F-250. That 350 has all kinds of Banks stuff on it, turbo, intercooler and the works and I can outpull it real easy even when I'm hauling twice the weight.

Maybe I should be investigating the 97 more! I've had it 3 years and never once found anything aftermarket on it. I bought it from the original owner after he died and it was always maintained at the dealer by me mostly. I seriously doubt it's chipped or anything.

 

Your 97 could be a cail truck and it will make more power.
Rear gear on both trucks the same?
Sometimes its just the smallest over looked thing.
Something like the map line is clogged. You checked the connections,
but did you see if it was clear. They have a habbit to clogg or leak
(dry rot).

Bill