stock659

I've had a kit on my 2000 for approx. 10,000 miles or less, today on the way home from work I look down at my fuel pressure gauge an the pressure was dopping down steadly and rebounding are 12-14. then a little further down the road it dropped again. this time I pulled over, got out looked around for a sign of leakage, found none. when I returned to the cab the pressure was normal 16, then all the way home. could this be a sign the walboro is going bad this soon? anyone have any ideas? one thing I need to check in the future is the pick up filter in the tank, it could be partially plugging. thanks stock659

Shovelhead

The Glacier Diesel kit (if that's what you're using) came with a small prefilter that gets installed just before the pump in the feed line from the tank.
Maybe yours is getting clogged.

http://store.dieseltruckresource.com/3flinst.html

I just bought two from the DTR Online store so I can change mine and have a spare.
Mine's been on for ~20,000 miles.

stock659

No, mine did come with a cleanable filter I cleaned in june and it was spotless. thanks for you thoughts.

Shovelhead

I wonder if the overpressure bypass valve might be hanging up.

Mine's been low a couple of times when I first fired it up (14-15 psi), but a couple of miles down the road, it's back up to 18 PSI at 65mph.
That's why I'm going to change the filter.

Nor_Cal_Angler

what guages are you running???

electronic (sending unit) FP or mechanical FP??

reason I ask...

I have the (in Sig) Quad Commander...

Electronic sending unit/digital guage...when all the problems came out about the sending unit's quad was suppling I was suprised beacuse I had no problems...then I started getting a bounce with mine as well...

I checked the walbro for all the common already listed items...leak, pre-filter, main filter, pressure regulator/by-pass, small hole for air to enter etc. etc. etc.

after all that I figure it was the sending unit...so I added a needle valve before the sending unit into the IP...snugged her down and backed it off a very little bit...

now I have rock steady FP...it takes a bit longer to read at the digital guage (in cab) ie..shows 0 psi for a minute..then jumps to 2psi then a bit further down the road..5 psi and so on...about 5 minutes into the ride and before I realize..I am sitting solid at 18 psi and it never drops down below 14 at WOT....

just to make sure about every 2 months I test it against a mechinical FP guage at the fuel filter and once I crank the motor over I am at 18 psi...

I figure with the needle valve being cranked down it takes a bit to read at the sending unit.

What I am saying after all of that is.....

could it be time for a new FP guage????

NCA

madhat

Where did you get it?

When I bought mine a long time ago, I got it from a rip off company, and they gave me a crappy bypass. If your bypass is not a round brass part, then you have a cheap one.

If you want to test the flow of your pump, take off the hose going to the engine, put a short length of hose back on it, and get a two gallon container. Turn the key on, see how long it takes to fill one gallon up... should be less than 60 seconds.

sheriffav8r

A good test is to bump the engine and check that the pump turns on quickly and creates good pressure at the IP. I had some problems with the pump cutting out and the truck running like EDIT with the pressure going from the usual 21psi down to 0. Sometimes it would hang up at 13psi or so and still run terrible. I troubleshot it to the quick-connector on the original LP wire next to the engine. I added a relay on that wire and now it runs flawlessly. I believe that if the pump works fine when you bump the motor it should work fine on the road. Any other problem is probably a wiring issue.... P.S. Get the Fleetguard FF5079 screen before the Walbro and use a good bypass (I use the Swagelok and it has performed flawlessly for about 50K miles)....

stock659

I've got a westech electric on the fuel canister and a full pressure from the injection pump into the cab. the kit came from wide open diesel. the pressure regulator is brass and adjustable. a thought a friend had, inside the regulator there should be a spring and ball. what if there are burs from the manufacturing process this could hang up the ball not allowing pressure to build. then if you stop the truck an idle or shut it off the ball would reset itself, showing no problems. anyone have thoughts on this theroy. thanks stock659

Shovelhead

Just finished changing my Walbro pre-filter.
Start-up showed 15 psi. (Grid heaters on)
As grid heaters cycled off, pressures came up.
After running for approx 5 minutes, idle fuel pressure back up to 19-20 psi.

Same as before.

(mechanical ISSPRO gauge plumbed with stainless braided line tapped off of the fuel filter canister)