bsummit

I'm about ready to pull my hair out on this one except i don't have any hair. Got a new lift pump last week. My fuel pressure was anly abnout 10 to 11 lbs when it was cool in the mornings. When it gets hot, which it's 92 now, the fuel pressure only gets up to 9 lbs and pulling a trailer, about 5k it drops to ablut 6 lbs. Could the pump be sucking air around the snap fittings in the line between the tank and the pump. The reason I say that is the one at the pump is real loose. I have 2 guages, an electric inside and a manual under the hood and they both read the same.
I am leaving on a 400 mile trip in less than a week. Can I cut the snap fittings off and temparerly use a 3/8 fuel line with clamps until I can get a relocation kit.
Thanks in advance..

JPR Ram

Do a search on this site and the other cummins forum site. But I bet 10 for a hundred that you're having pump cavitation issues.

2500Ram

They could be sucking air but I believe you would see different readings on your gauge if they were, fluctuation more or less, not a steady drop or low pressure readings. I just put in some hose clamps on the supply and return lines thinking it was sucking air but I still have the same readings. My lines were very loose from the hard lines to the rubber lines. It was better for about a day but then my symptoms came back. I just ordered a walbro setup form Glacier Diesel. Hopefully after the install all my FP issues will go away.

Good luck.

bsummit

If I'm having cavitation issues, what can I do to fix it?

2500Ram

If all my reading lately is correct you either need to A, reduce the input restriction and or B output flow restriction. My solution, still not here yet was the walbro GFS-392 with new fuel lines http://www.glacierdieselpower.com/pr...?pf_id=3929852 this is the best deal for a complete kit I could find.

Search the 24V section for the Cavitation video link. Tons of reading and debate weather cavitation is happening or if the spring ball is getting weak in the LP's. (hope I got that right) It's been talked about in the last few days so it's pretty recent.

Good luck. I just got back from picking up the kids from school and my FP reading with normal driving would fluctuate from 11 psi to 4psi to 11 and back 4 times within 3 seconds with NORMAL acceleration. WOT about the same but they will stay one way or the other. This is with a "new" less than 1 yr old lp and about 10,000 miles on it. It's been doing this for at least 6 months.

00' Quad Cab

Here is a cheaper alternative to Glaciers Walbro kit, this is what I have and am very happy with.

http://www.wideopendiesel.com/

Jason was a breeze to do business with.

bsummit

Ok guys, I may have my problem solved. I haven't driven it down the road yet.
I have been using fleetgard fuel filters and the last ones I got they had changed the item number and the filter has a different top on it. I have the tapped filter top that Geno's sells and that's where I get my fuel pressure at. This new fleetgard filter fits real tight into the top of the filter housing and I think it was restricting the fuel pressure getting to my sending units. I just changed the filter with a wix and it has the same top as the old fleetgards. When I cranked up the fuel pressure went to between 13 and 14 PSI and was holding steady, which is about what it should be with a new LP. Will let everyone know if that was the problem after I drive it later today.

bsummit

Ok I test drove it and everything is fine. I have and maintain a steady fuel pressure. It drops to about 10 PSI at WOT and runs about 11 at 70 and 75 MPH. It's not quite as much as when I changed LP's the last time but it's sure better than what it was doing. My next project is the big line kit from Geno's and I hope I'll be through for a while.

PaulDaisy

As a matter of fact, I do notice a slight pressure drop as fuel gets hotter, and on hot days. On cool mornings I get 15 psi. Later on it drops to 13 and 10 at WOT.
-P