FUEL RAIL PRESURE

[BUKWAKR]

whats everyones fuel pail presure @ idle, Scott said it should be around 5500-5600 psi. Mine stays in the 5000 psi range and then this morning I noticed it jumping between 5500-5700 psi then it fell off to 5000 again my mileage with the spartan tuner is off by 2-3 mpg verse what most of you guys are posting and was wondering if this may have something to do with it. My truck is a 250 c/c lwb with a delete pipe tuner and intake and around town i'm seeing 12.6 to 13 mpg. I'm heading down to VA. friday so i'll get some good highway numbers.

Darrell

[b_hugie]

I see right around 5200 psi at idle. There are a lot of factors that could influence the mileage you are getting - Driving style, tire pressure, driving conditions, altitude, cat. converter (on or off), which spartan tune you are running, etc. On an average I would think you should get better than 13 if you are running stock tires and the spartan 210/250 tune. If I take her easy i can get 15 around town with some rather large tires on my truck.

[BigIslandBoy]

Are your fuel rail pressures constant at idle? Mine seems to flutter between 4900> and <5200 . Just wondering if this is normal? Truck runs great other than at idle with the a AC on it like it misses once in a while.

[fdxgnd]

Mine surges as well. Loaded the 275 tune yesterday and it didn't do it until this morning. Seems to do it when it is colder. It didn't do it when I drove home today and it was about 55 degrees. I never had this issue with the 250, but I will keep watching to see what this may be.

[fdxgnd]

I'm gonna bring this to spartan's website and see if we can get some help.

[jason1168tx]

I think the issue might be with the EGR valve. I notice what feels like a slight miss at idle whenever the EGR valve opens or closes. I also think that the EGR valve opening and closing may be what is making the engine feel like it is surging under moderate (15-30psi) boost conditions. I would like to see Spartan or SCT disable the EGR system and just leave the valve closed. Sure would help with EGT's.

[fdxgnd]

My egr is disabled. I had my truck out in colorado at elite diesel. They replaced both turbos, injectors, egr delete kit, and wastegate. Still, fuel rail pressure surges.

[Pahrump]

Mine moves around a little, but does not affect driving at all. There are tons of things that can make this different between trucks...intake, amount of oil on filter if its oiled....cover on or off your intake, exhaust mods...tons of things.

[Rudy's diesel performance]

mine moves too, does not look like its surging though

[fdxgnd]

I agree with pahrump. Mine doesn't do it all the time. Only when it's cold outside. Doesn't affect wot at all. I can feel it if driving around town going up hills. Fuel rail pressure fluctuates about 2000 psi. Truck kind of gets sluggish. Once the temp outside warms up it seems to stop. Doesn't really bother me that much because when I really get on it it does what it needs to.