Can anyone tell me what the normal operating pressure is for the fuel system, what pressures set a code, and if there is a certain time it has to see a certain pressure before it sets a code? My truck has been into the dealership severa times for the same problem, losing power at full throttle with a heavy load, and they have been able to duplicate it, but unable to find the problem. I hooked up my scan tool, and drove it today and noticed the fuel pressure was all over the place, from about 200 kpa, to about 63000 kpa (about 30-9000psi if my math is right.) I know it wouldn't run at all if that was really the pressure, but shouldn't it set a code? Maybe my scan-tool is not getting a good reading?

 

you math must be wrong.
you need to look at vcv_f , pcv_f, frpv, frpv at koeo, short term fuel trims 1-8, frp# at idle. to start anyway.

codes you could see p0088,p0087,p2291,p0003,p0004 are just a few that I can think of right now

operating pressures should between 5000-27000 psi.
its not uncommon for frp pid value to change rapidly.

 

Thanks for the quick reply cheezit. I fixed a typo on my first post,and checked the conversion. 200kpa=29.007psi, 63000kpa=9137.317psi. Would these set a code, if the low value was only for a second? My scan tool only displays one fuel pressure, and key on engine off is 0. I have an appt at a different dealer on Tuesday, just wondering if this is really a problem.

 

9137 may or may not set a code depending on what speed, load, and comanded pvp vcv was vs. the frp and and frp dsd.
Im sorry if this makes little to no sence to you. I realy dont know how to better explain it.
it will be very hard to fix unless someone get it to do it with the ids hooked up and monitering the correct pids if it wont set a code.

 

Ok, like I said I have an appt. at a dealer on Tuesday, and we are going for a drive with my trailer and his computer. I will tell him what I saw, but this will be my fourth time driving with someone with a computer hooked up, and I am looking to at least narrow it down so I don't have to keep burning fuel once a week on this.

Just to confirm, the 29psi would definitely set a code if that is what the computer was really seeing, right?

 

ahh somehow I missed the 29psi. the truck wont run with much less then 5000psi (4800 is min) and has to see 5000 psi to start.
so if you hit 29 psi your engine just shut off.

 

No she starts and runs good, except when pulling the trailer up hills. The mileage loaded and unloaded is worse too. I am guessing the fuel pressure sensor is f'ed up and giving a false reading, and the computer is trying to compensate? I just kinda thought a low reading like that would set a code.