Loud Injectors/Rail Pressure Spikes At Light Throttle Only STFT?

[Powerstroke Man 6.4]

I've been trying to figure this out for a while now I just haven't gotten to make a thread for it getting rail pressure spikes (rail pressure high alarm goes off on the dash daq its set to 24500) (it started awhile ago/doing it once and a while,now its pretty constant) at light throttle only. I changed the tune down to the 300,275,250,210 same issue.

I replaced the fuel filters with OEM filters as always same issue. STFT with 1,2,3,6,8 are between 0.6-0.9 while 4,5,7 are around +0.25 - +0.29 at idle any problems with those numbers?

Injectors/rattle seem to be getting louder almost got a 6.0 sound at idle at WOT injector rattle is quite loud. Rail pressure and other PIDS are normal at idle and driving truck holds 24500 at WOT.

no white smoke no codes truck seems to not have the power it had before.

Drained the water separator fuel is clear/clean no water/debris whats the symptoms of a tired LPFP? truck got 94K on its second fuel system and LPFP system has 50K and was replaced by Ford.

Change the fuel filters with OEM every oil change 5-7K always run power service silver bottle drain the WS every month.

Thanks

 

[webb06]

When the injectors chatter seems to be loudest is fuel pressure higher than it should be? That's usually what causes the chatter

 

[Tree Trimmer]

sounds kinda like a surge issue.

mine did the same thing. got with matt, did a little data logging to get it narrowed down to what pedal position and rpm and gear, he did a little revising, and fixed.

 

[Powerstroke Man 6.4]

When the injectors chatter seems to be loudest is fuel pressure higher than it should be? That's usually what causes the chatter

What would cause high fuel pressure? everything stock except for the tuner,exhaust,cai,and MBRP cac tube.

 

[webb06]

What would cause high fuel pressure? everything stock except for the tuner,exhaust,cai,and MBRP cac tube.

I'm just thinking the rail pressure sensor

 

[Powerstroke Man 6.4]

sounds kinda like a surge issue.

mine did the same thing. got with matt, did a little data logging to get it narrowed down to what pedal position and rpm and gear, he did a little revising, and fixed.

even if it does it with lower tunes 150HP tunes and lower? kinda hard when spartan don't do custom tunes.

 

[Powerstroke Man 6.4]

I'm just thinking the rail pressure sensor

Ford changed the RP sensor (3rd sensor) last time I took it in should I change it again? Thanks for the info.

 

[tight]

if you have the new software in you're tuner you can turn the sensor off.

 

[Powerstroke Man 6.4]

if you have the new software in you're tuner you can turn the sensor off.

You sure its the RP sensor? I don't think the truck can run without it LOL. The only thing spartan said you can change with 7.10 update I heard is the code for aftermarket LPFP's.

 

[Tree Trimmer]

even if it does it with lower tunes 150HP tunes and lower? kinda hard when spartan don't do custom tunes.

dont matter the tuner.

matt explained it to me like this.

even if you give the same files to 10 different trucks, the way the computer in each truck interprets the multitude of tables will be slightly different. it shouldn't be, as it's a computer, but you need to take into account the "health" of the various sensors feeding input the the computer, and the health of the various components in the truck as well.

mine had no problems for like the first year and a half. then developed a surge. with no change in anything.

we narrowed it down to it was jumping between two tables creating the surge.

he did a little tweak, all fixed.

so, ya. don't matter who's tunes they are.

 

[Powerstroke Man 6.4]

dont matter the tuner.

matt explained it to me like this.

even if you give the same files to 10 different trucks, the way the computer in each truck interprets the multitude of tables will be slightly different. it shouldn't be, as it's a computer, but you need to take into account the "health" of the various sensors feeding input the the computer, and the health of the various components in the truck as well.

mine had no problems for like the first year and a half. then developed a surge. with no change in anything.

we narrowed it down to it was jumping between two tables creating the surge.

he did a little tweak, all fixed.

so, ya. don't matter who's tunes they are.

Spartan wont do "custom" tunes though I 100% agree with you and Matt.

 

[Tree Trimmer]

hence why people are running less and less spartan, and more everyone else's.

1 size fits all is nice, but sometimes you just need a tweak not a complete custom file.

do you by chance have a buddy close by you can try his tunes with? that would at least tell you tuning or mechanical and save you from throwing a bunch of parts at it to find out its the tune.