Lightman

Hey guys. I'm curious- those of you that have fuel pressure gauges, how many miles do you go before you start pulling down to 3-0 psi during medium to low acceleration? I was previously changing my fuel filters every 10,000 miles, but since I've installed the gauge, it seems like after 5,000 miles or so the filter starts getting restricted. When I throw a fresh filter in, I typically get 7.5psi at idle, and around 6-6.5 at cruise. It barely drops below 5psi during normal and mildly aggressive driving. When I have the box turned up, I have to have it in 100hp mode and stomp it pretty well to pull the pressure down to 0psi. After about 5k if I have the box turned up at all I can hit 0 really easily. That makes me wonder how some guys go 30-40k between changes. I may do a fuel analysis test just to be sure my station isn't serving up extra dirty fuel that's prematurely clogging my filters, but I doubt it. The guys that own/run this station are very interested in diesel fuel and fuel quality, and love to talk about it. Any info appreciated!

Lightman

91 views and nobody has a fp gauge and monitors fuel filter life??

AK RAM

The FASS is not really a fair comparison to the stock setup, but after 15,000 miles on the same filter, pressure is now down about 1.5 pounds on average in all situations versus new. For what it's worth.

Sailpipes

Good question. I don't really have enough miles on mine yet to see (just passed 10K). Normally I don't see much movement in the needle though. Just recently I noticed it was staying around 2.5 to 3.5psi. Changed the filter a few days ago and no change. Gonna call to make an appointment this week to have the situation checked out. I installed the gauge around 7K miles I believe. At that time it usually read around 5-6 psi.

Superduty

Where does one tap into the fuel system to install a fuel pressure gage ?

Dodgezilla

I've always had to change my filter at 10,000 miles for some reason..

Jerry R

I only have around 8,000 miles on my AirDog filter but see no change in presure yet for what it is worth.

Lightman

Thanks for the replies guys. It sounds like I may be going thru them a little fast, although a few of you guys have diff setups. I wonder if my station is dirty.

Sailpipes- I had the same problem, low readings/slow response, and found it was because I listened to Geno's and didn't put any antifreeze in the line between the isolator and gauge, since it was a short run. As soon as I did that as instructed by dipricol support, it's much more responsive. I'd say it moves the same speed as the boost gauge..

Superduty - via a tapped banjo bolt on the cp3, or geno's billet tapped fuel filter cap. Mine is at the cp3.

Badunit

I've had a gauge for more than one filter change. I've never seen much difference from new to when I've replaced the filter using the recommended schedule. I don't romp on it hard very often, though, and that's when a dirty filter would show up worst My observations are mostly idle, highway speed, and moderate acceleration. I tend to watch the EGT gauge and the road versus the fuel pressure when I romp on it. I'm thinking of extending the time I leave the filter in and basing the change on fuel pressure versus mileage; it's come out pretty clean the last two times on the recommended schedule.

GrandpasRam

Lightman, my '03 that I just traded out of was stock fueling except for the FP guage. For the '03, I was pulling 8.5 lbs at idle, 6.5 to 7 at normal cuise. Pressure started coming down a half pound at about 9 - 10 K, which is when I would change the filter. Had 35K on the truck. Hope this helps. I don't have guages on the new '05 yet, so don't know what the pressures will be, but expect them to be pretty close to the readings on the '03.

Lightman

Thanks for the info badunit and grandpasram.

Once the filter is 'dirtry', my gauge would clearly dip a few psi under moderate acceleration...like keeping up with traffic or barely accelerating more than they were, say from 0-40mph, would drop me from the 5psi at idle down to like 2psi or 3psi under that moderate acceleration. This was with like 5k miles on the filter! Brand new filter would idle at 7.5psi, after 5k on the abovementioned filter, I would be around 5.5psi.

I'm just trying to determine if I should go thru the $60 expense to test my station's fuel or not. From what I'm reading, it sure sounds like mine is clogging faster and more significantly than others. What makes it even worse is that 50% of the fuel I burn goes through an additional 2 micron racor filter before it even hits my tank, which should EXTEND my filter life... grrr

GrandpasRam, you might see different pressures or behaviors in your 05, since they switched the lift pump to in-tank. That will be interesting to watch. PS nice choice of quads, I ride a prairie as well

GrandpasRam

Thanks for the heads-up Lightman. BTW, that Kawasaki runs really good, the only thing I don't like is that it is full-time 4 wheel drive instead of selectable.

1sttruck

I've always needed to change fuel filters at about half the 'normal' frequency, and I've come to assume that it was due to low fuel pressure. I ran across one maintenance facility that started rejecting delivered vehicles with the Cummins if the idle or high rpm fuel pressure was too low. I'm no diesel mechanic, but it seems that low fuel pressure could be due to either a wimpy fuel pump or excessive fuel being diverted back to the fuel tank. Anyone know how the two systems work together ? Would it be possible to add some sort of adjustment to the fuel return system in order to get a few more miles out of the filters, at least to the recommended change interval ?

Lightman

1sttruck, just curious, but why do you think low fuel pressure would cause the filters to clog earlier?

I know my fuel pressure isn't considered low when compared to other trucks of my year with stock lift pumps - 7.5psi at idle and 6.5psi at cruise is pretty normal. I just notice my fuel filters start plugging and pressure dropping considerably at about 5000 miles into the filter.

Grandpasram I hope that in-tank pump setup proves to give more pressure than the one I have. I know it will be more of a pain to fix/get to if you do have a problem. As for the kawasaki - I have a 650, which has a push button 2wd/4wd choice, so I don't share your issue. I can imagine that gets you a nice upper body workout with the steering though, if it's in 4x4 all the time I have 2400 miles of bomb'ed abuse on that quad and have only had ONE very minor problem.

DR3500

sailpipes, make sure your isolator isn't maxed out, Mine did about the same thing and I drained it of fuel and put more antifreeze in it and it is back to normal.

I change my fuel filter every 7-8K mi. I don't see any noticeable drop in fuel pressure in that time.