So I am currently at work 65 miles from home. On my way in this morning at about 40 miles in or so, my fuel pressure started to flutter and then dropped to 0. I had to baby her through the back roads to get here. I was doing a consistent 65-70mph until it happened. I have a walbro lift pump, vulcan pick-up and have replaced the fuel filter within the last 1000 miles. The truck is absolutly fine now (just went out and drove it around). I would not be concerned except the exact same thing happend on friday when i went to work. The truck drove fine all weekend long so i figured the problem went away. Yes, that was a dump assumtion, but i could not get the problem to repeat itself. I just don't want to have it happen again and kill my injection pump. I have put enough strain on the injection pump getting it to work this morning. I am showing no check engine lights either. Does anyone have any ideas?

 

Possibly a bad load of fuel??? Try the water drain valve and catch what comes out. Have you run bio in it lately?? If so you might have crudded up your new fuel filter prematurely. Good luck with it!!!

Gary

 

Just opened the drain valve and caught a sample. Looks and smells like clean yellow diesel. I have never run biodiesel, but i did have another diesel guy at work tell me it could be the filter.

 

It could be the filter but you also need to check electrical connections to the lift pump. Also is your fuel guage an electrical one or mechanical? I would suspect the guage or a bad electrical connection to the pump. IMO a dirty filter would not cause a drop in pressure from normal to zero and then correct itself with a restart. The same would go for a sticking bypass valve. I would think it would have to be complete electrical failure to the fuel pump or a bad connection on the guage. Good Luck.
As a afterthought be sure and check the ground connection at the fuel pump. That would be a likely place for a bad connection.

 

My gauge is mechanical w/isolator (i know they suck). I know the gauge is right when it reads 0 and the truck is bucking and studdering. I will check the pump wiring. Thanks. Any more ideas out there??

 

I just remembered that as the truck was studdering this morning it would get worse when i made hard left turns and significantly better when i made hard right turns. Would a pick-up issue cause a 0psi condition with almost a full tank of fuel?

 

I can tell when my tank is getting low. I start to see fuel psi drops on acceleration and stopping..

 

On your walbro setup do you have a pre filter before the walbro?
I had the same symptoms, My pre filter was a G-15 fram which is a paper media filter (not knowing)I think it was collapsing with the suction of the pump, I have replaced it with a Napa Gold 3253,Which is a mesh screen 120 micron.

Hope it helps.

 

ditto on Truckman's response. I didn't have the pre-filter and my started running really crappy. Pulled the pump off and the inlet screen was filthy! Called Glacier anf they said to just spray it out with Carb cleaner or something similar. Installed a pre-screen and now it works like new again.

 

I agree with truckman and thellums. I didn't realize that your truck was running badly when the guage showed 0 psi. It very well could be the filter on the suction side of the pump or if no filter a clogged screen on the inlet of the walbro. Good Luck

 

I have a napa gold prefilter. I will check it tonight when i get home and hit it and the pump with some carb cleaner. Here is what i learned on my crappy ride home last night. The problem shows up within 25-30 min without fail every time, under any driving conditions. If i try to restart immediately, the problem is still there. It i shut the truck off for 10 min or so, i get another 25-30 min. My theory is this... the relay for the lift pump is overheating and separating the internal contacts causing the pump to shut off and 0 psi of fuel. Possibly a bad or starting to fail relay. I have not fully verified this yet, but i am going to remove the relay and jumper out the connection and drive around for 45 min and see what happens. Thoughts?

 

Sounds like a good possibility. The jumper will tell you in a hurry. I have one in my toolbox to purge lines without starting the engine. Good luck

 

Could also be the prefilter or pump getting plugged from junk. Shutting it off lets the junk flow out of the screen, and another 20-30 minutes it clogges back up again. Had a couple of gassers do that. Any biodiesel? Could be some algae?

 

Some Napa Gold Fuel filters are paper media,,Thats what I had,,Thats how I found this out..Napa filters are wix filters,You can go to the wix website and cross ref your filter number the website will tell you what media is in the filter.

 

I am using a NAPA Gold 3003 clear plastic paper media pre-filter on the suction side of a 392. I can see the filter media, and it does not look any different when the Walbro is running than whan it is not. Just normal looking filter.
-P