Fuel pressure

[camping fam]

We have a 2006 pusher with a 300isb and recently had some issues with the frame mounted fuel strainer or as Freightliner calls it the rock catcher it was almost totally clogged up anyway fast forward had some issues of what felt like our moho was running out of fuel and after some research decided that after changing the filters and still the same issue maybe we had a lift pump that was beginning to act up especially after the clogged rock catcher incident and so we checked the pressure on the output of the filter water seperator prior to the new pump was 8psi at idle we installed the new pump and a digital fuel pressure gauge what fuel pressure should we be seeing now?

[Skip426]

The 8 PSI, at idle for the original pump, doesn't seem that far off for the , 06 ISB, I'm assuming Common Rail Injection , the big issue the Dodge Cummins, ISB of that era had was maintaining the pressure under load.
The main injector pump, uses only 30% of the fuel supplied to it at wide open throttle, the rest is used for cooling/lubrication, and returned to the fuel tank. If your digital gauge shows, 8>10 PSI, and maintains that at full throttle , and your performance is back to normal. Your OK.
If still in doubt, a call to the Freightliner free help line. may answer you question. Have your serial number handy.
1-800-FTL-HELP
I have the number written out in about 5 places, and of course right now I can't find any of them.

[camping fam]

Yeah FTL help is always great got a young sounding guy on this question he said to call cummins cummins said they measure off of volume.

[Skip426]

Sorry , should have thought of that , Cummins, would either supply the pump or send the specs to the manufacturer; if the pump is not mounted to the engine.
Dodge/Cummins, had a rash of failures of the lift pumps. In, 98>02 24 valve engines and, 03>05 24 valve Common Rail, the lift pumps were mounted on the side of the engine, and didn't last long; due to the heat and vibrations. Finally in 06, Dodge moved the pump back into the fuel tank, and ran an update campaign on any 98>05's that failed.
If you have any more problems , I'd move the pump , off the engine , if that's where it is, and put it as close to the fuel tank as possible.
Electric pumps , push better than they pull.

[camping fam]

Took a test drive today and the pressure at idle was 12psi cruising down the road 10-11psi hills 9-10 psi and on a large hill 7 psi for a few seconds then back up to 8psi then climbed back up to 10-11 psi.

[quadder]

Originally Posted by camping fam

Took a test drive today and the pressure at idle was 12psi cruising down the road 10-11psi hills 9-10 psi and on a large hill 7 psi for a few seconds then back up to 8psi then climbed back up to 10-11 psi.

You said you installed an electronic pressure gauge. What type did you use, and where did you install it?
I have the same pressure problem with my moho, and freightliner changed the filters, and no improvement. They are going to try a new lift pump next.

[camping fam]

I used a digital gauge from www.prosportgauges.com there evo series looked cool and @ $100 or so I went with that one it is set up to run white during the day and then green when the headlights are on. I used a 12mm x 1.5 banjo bolt from www.torkteknology.com this snubber is used by alot of the cummins pickup truck guys and it fits perfect on ths output side of the filter to high pressure pump this was $20.95 I drilled a hole in the dash which was super scary but it turned out fine I actually put the gauge in a spot where if I was concentrating on driving my wife or daughters could see the pressure. I ran 18ga wire from the sending unit they send you with the gauge all the way up front found a good power source per the directions and that was it.

I am not a electrical or mechanical person by trade but I am not afraid to jump in and do something when I need to all an all it was alot simpler than you would think.

I have learned that the fuel pressure makes a huge difference in these machines if you have a lift pump that is weak or starting to go out you might be able to notice it by low power.

Cummins makes a lift pump relocation kit it is around $400 with the new pump I went with this as I am a firm believer in factory parts but you do what you want on that end of it.

Personally I would like to see closer to 15psi at idle I am still messing with a couple of things and in the process of building a garage for the moho so time has been a little scarce.

Please let me know how everything turns out and hopefully you guys will back up and camping real soon. If you have anymore questions please contact me.

[quadder]

Originally Posted by camping fam

I used a digital gauge from Prosport Gauges - Boost gauges, Wideband Air Fuel Ratio, 80mm tachometers, 80mm Boost gauges,Oil pressure gauges, peak warning Gauges. Wideband Air Fuel Ratio Gauges, 45mm gauges there evo series looked cool and @ $100 or so I went with that one it is set up to run white during the day and then green when the headlights are on. I used a 12mm x 1.5 banjo bolt from Tork Teknology this snubber is used by alot of the cummins pickup truck guys and it fits perfect on ths output side of the filter to high pressure pump this was $20.95 I drilled a hole in the dash which was super scary but it turned out fine I actually put the gauge in a spot where if I was concentrating on driving my wife or daughters could see the pressure. I ran 18ga wire from the sending unit they send you with the gauge all the way up front found a good power source per the directions and that was it.

I am not a electrical or mechanical person by trade but I am not afraid to jump in and do something when I need to all an all it was alot simpler than you would think.

I have learned that the fuel pressure makes a huge difference in these machines if you have a lift pump that is weak or starting to go out you might be able to notice it by low power.

Cummins makes a lift pump relocation kit it is around $400 with the new pump I went with this as I am a firm believer in factory parts but you do what you want on that end of it.

Personally I would like to see closer to 15psi at idle I am still messing with a couple of things and in the process of building a garage for the moho so time has been a little scarce.

Please let me know how everything turns out and hopefully you guys will back up and camping real soon. If you have anymore questions please contact me.

That's awesome. Thank you very much. I'll let you know how it all works out. It will, one way or another, since failure isn't an option.
Rob

[onechaddude]

Thanks for the info guys. I am gonna look into this gauge myself as I have a ISB 325 Cummins. I have heard for a couple years about this but wasn't sure of the how to's. I am like camping fam in that I'm not a mechanic but can do what I need to. Albeit maybe a little slow. Thanks

Chad

[Vickie 4369]

Originally Posted by camping fam

I used a digital gauge from www.prosportgauges.com there evo series looked cool and @ $100 or so I went with that one it is set up to run white during the day and then green when the headlights are on. I used a 12mm x 1.5 banjo bolt from www.torkteknology.com this snubber is used by alot of the cummins pickup truck guys and it fits perfect on ths output side of the filter to high pressure pump this was $20.95 I drilled a hole in the dash which was super scary but it turned out fine I actually put the gauge in a spot where if I was concentrating on driving my wife or daughters could see the pressure. I ran 18ga wire from the sending unit they send you with the gauge all the way up front found a good power source per the directions and that was it.

I am not a electrical or mechanical person by trade but I am not afraid to jump in and do something when I need to all an all it was alot simpler than you would think.

I have learned that the fuel pressure makes a huge difference in these machines if you have a lift pump that is weak or starting to go out you might be able to notice it by low power.

Cummins makes a lift pump relocation kit it is around $400 with the new pump I went with this as I am a firm believer in factory parts but you do what you want on that end of it.

Personally I would like to see closer to 15psi at idle I am still messing with a couple of things and in the process of building a garage for the moho so time has been a little scarce.

Please let me know how everything turns out and hopefully you guys will back up and camping real soon. If you have anymore questions please contact me.

Look in to this, it is the End all in Diesel fuel supply systems.
http://www.fassride.com/

Lifetime pump, water separator and filter all in one unit.

I have installed hundreds of these on Dodge pickups.

Ted.

[Ray,IN]

On Dodge CTD's (mine was 1996), the flexible lines that connect to the lift pump can look great, but fail inside and restrict fuel flow as they age. They will cause lift pump failure, which in turn will cause injector pump failure. Don't know if you have flexible lines. Had I kept that truck I would have installed a FASS system too. Some locals just added an electric diesel fuel pump prior to the OEM lift pump.

[camping fam]

I am thinking about adding a fass system at the tank to push the fuel 30+ feet rather than suck it 30+ feet I guess the normal pump setup could stay or maybe do away with it

[Ray,IN]

It could stay, as excess fuel is returned to the tank. A good site to learn more about the ISB engine is: dodgeram.org

[camping fam]

Went for a hour drive today and pulled some big hills fuel pressure stayed around 9 would go up to 10/11 and on big hills drop to 8/7 and would blink on 6 for a second on a huge hill.