Over the least few weeks I have been testing the fuel system trying to find out if it's the reason why the truck is low on power, boost and EGTs.

-Started with fresh fuel filter.
-installed a fuel pressure gauge on the cowl. (plumbed to fuel bowl)
-dropped the tank, did the ITP kit and checked for clogs. added a pre-pump filter. tank was very clean.
-tried 2 different shims in the fuel pressure regulator. No shim was 40-50psi. 0.023" shim was 40-55psi. 0.055" shim is 40-55psi. the pressure reading can be anywhere between the numbers under most conditions; hot, cold, light accelerating, idle. Pressure drop from idle to WOT is usually 5-8psi.

So it seems that the pump cannot provide enough volume to keep the bowl pressure regulated. Adding a thicker shim has a minimal effect, none under WOT. The SOTP meter is the same at 40 or 55psi. Wondering if a new pump that would hold 68psi will change anything.

I would prefer not to buy a new pump unless the old one really is 'inadequate'. whatcha think?

thanks

--------------------------------------------------------
Justin
2000 F-250 PSD Lariat - 4" lift, 35s, Superchips, 4" exhaust, gauges,
6637, CCV, hutch/poon, 1000W stereo, car seat.

 

You would notice some difference, but not much.
Mine would drop to 20 at WOT and it still would accelorate to the rev limiter, just be really flat on power above 2500 rpm.

 

The factory fuel pressure is around 55PSI +or- 5psi. with .023 shim I was idleing at 70psi, but could drop the psi to 30 when I got on the loud pedal.

I did not like that much of a drop so I went with a new fuel system. I would start witha new FPR spring, and poppet and FPR housing (its alot cheaper than the pump)if still no pressure then go for the new pump.

 

i shimmed mine with a BB then plumbed a gauge in for giggles (thanks again for the fitting brandon) and my fuel pressure is a constant 95-100 psi. i have read that its okay for it to be there, the only thing it will have an effect on is pump life or longevity. Now my brother in law on the other hand that has had some fuel pump issues as well (thanks again Brandon for helping s out) just installed a Walbro 255LPH hi-pressure pump on his and wow. drives like a bat outta hades BUT his new consistent fuel pressure is 140psi (no shim)!! He posted a thread asking for opinions on how this would or would not adversely affect things but no one has responded yet. i am curious to hear as well as when my pump dies i thought of going with the walbro pump too. Also, FYI, there are some chinese knock off walbros out there and thos eseem to be the ones people are having problems with. If you get one buy from an authorized walbro dealer (still cheaper than a stock pump, less than $140) but those are the ones the dodges seem to like and have good luck with them lasting many years as well. Just my .02

 

The fuel filter lid is made out of plastic. There is no way that I would trust that to 140 psi.

 

I m the b i l with 140psi and like you am worried about plastic top also. My psi is not great for pump life and i have read other problems . Hope i will have this worked out soon. One good thing pump is ok price and i'm testing it real hard we will see how long it last or what gives up first.

 

I consistently hold 68-72 psi. I have not seen it go down very much at WOT. Like OP said ~5psi, depending. I would sure change it and keep the old one as a spare.

 

If you watch e-bay you can pick up a new Motorcraft pump for @ $120

 

Real quick, need to get going to work.
You could solve your excessive pressure problems by installing a larger pressure regulator. I believe that your much bigger than stock fuel pump is simply overcoming the tiny little pressure regulator in the fuel bowl and the pressure is going too high.
I recommend something less than 75 psi. 60 is better.

 

Another thought.
Fuel volume in all cases is much better than a bunch of fuel pressure.
Maintain 60 psi across the board is much better for making good power than having 100 psi and it drops off at WOT.

 

My fuel pressure is 15-20. Truck runs like crap but will throttle up to 3000 rpm’s a little on the slow side. The problem is when you put it in gear it goes limp and has intermittent surging. I’ve checked the pumps, checked the fpr, even did the bb trick. I don’t have any leaks anywhere. Could my pump just be bad? Thanks

 

you have been found guilty of practising necromancy......

Seriously though, welcome to the forum, you should start your own, new thread with this question, that way its easier to keep everyone on track with diagnostics, and recommendations.

 

If your fuel pressure is low all the time, check the pressure regulator on the outlet side of the fuel filter housing.

 

I think pretty dam awesome Kwikk is still an active user and replied.

 

Mine suddenly lost fuel pressure bigtime today and is now barely drivable, but then it dawned on me that last pump I put in way back in 2018 was like 175,000 miles ago, so it's got some hours on it. That's a pretty solid guess at that age isn't it? Wasn't the filter...it was way past due at 25k or so but putting a new one in didn't fix anything. Nor did filling the tank...it was down pretty low and I've heard the stories about the foot falling off the sending unit in the tank. Ordered a new Bosch one from Rock so we'll see if that fixes anything. I've never touched the fuel bowl or regulator and assume that's all original. It made it 320 miles back to Elkhart from Conneaut, OH just earlier today is the funny part, then started acting up on the way back from the washy-wash. Sometimes it's better to be lucky than good I guess.

I didn't see the need to start a new thread either. Did a search and this one hit the nail on the head so figured I'd add to it.