Good afternoon everyone, i have a 1990 w250 that has recently had some pump work done to it. The pump started leaking and I removed it and had it resealed by a real good injection pump shop. The guy at the shop installed a 3600 govenor spring, he said he trimmed the piston to 2.5mm overstock, and machined the fuel screw for further travel. It was a day and night difference overall on the performance of the truck. My question is that the other day while i was doing about 70mph i punched the skinny pedal and the truck acted like if there was no fuel, this only happens around highway speeds. In town the truck will work just fine. I am overall satisifed with the low end and top end performance of the truck but what could be causing this "defuel" situation?

 

It could be as simple as an old fuel filter restricting the flow of fuel and you only notice it at WOT on the highway.
Or it could be restricting the flow with some partially gelled fuel if you are in a cold place.
I like to start cheap and easy at first.
Do you have a fuel pressure gauge?

 

No fuel pressure gauge but i will start by replacing the fuel filter. Its been about 6 months ago since i have replaced it. I live in southwest texas and it hasnt been real cold down here, it was 42* this morning.

 

That ole' lift pump might not be able to keep up with the volume of fuel.

 

Thats exactly what i was thinking because again, it only does it at highway speeds and at wot. Around town everything is normal.

 

Proper diagnostics is the fastest and least expensive path to a repair.

You're blind without a fuel pressure gauge, either temporary or permanent.

 

In this case, im gonna install one temporary, how would i go about installing it?

 

The way most of us do it is to replace the banjo bolt with the bleeder screw in it on the fuel filter with an alternative that has a pipe thread hole instead, then plumb from there. Part can be had at Geno's Garage.

 

I put a fuel snubber in place of the banjo bolt on the fuel filter and a NoShok 0-30 psi fuel gauge (made in Germany) on my truck. Nice to know that my lift pump is working. I bought the stuff on Fleabay for about $40. The down side is that I can't see it from the cab. You could rig a tube and put the gauge in the cab but I'm not big on fuel in the cab. Pics to follow. I'm still getting used to the new photo system.

 

Mine is the pipe thread banjo as I said, small copper to a sending unit mounted on the firewall, pinched with my trusty dusty vice grips for snubbing. Gauge is electric.

 

Hi - I see 2 parts at Geno's -

1/ BF-LONG-TAPPED with large diameter fuel ports for $7 (+ $4 for two gaskets)
Steel Tapped Banjo Bolt - 3/4 SAE Fitting-Geno's Garage

2/ BF-BBS010 12mm banjo snubber with gaskets for $22
'98.5-'09 & '89-'93 Dodge Cummins 12MM Banjo Snubber-Geno's Garage

They look similar in design - which one would you suggest ?

 

I just spent 1/2 an hour on Genos web site.
Looks like the parts are a little different than when I got it but.
I ordered the:
Part # is:
Vulcan_Test_Kit

I though they had some banjo bolt that already had Schrader valve in them, but the 1st bolts you listed would work.
You would just need to get your own valves for them.
I got several banjo bolts and installed them on a few of my 12v trucks so I can check fuel pressure as needed on each while only having to by one gauge.

 

Would the larger ports give a false reading?
I plan to install a mechanical fuel pressure gauge on the banjo.

 

No, it shouldn't.
You would just need some sort of pressure snubber to keep the psi pulses even, or it will destroy most gauges quickly.

 

You can get the snubbing needed by remotely mount the sensor, feeding it with small copper tubing, and pinching said tubing almost shut with a pliers.