Ford Powerstroke Diesel Forum banner

Fuel pressure info

26K views 30 replies 6 participants last post by  gwright73 
#1 ·
My 2015 6.7 will not start. Dead engine cranking with P2291 low fuel pressure. I replaced the low pressure pump. I also found the pick up valve in the fuel sender was stuck closed. Both of those issues are now resolved. I cannot fully bleed the fuel systems no matter what I have tried the low pump still squeals and airates. I have borrowed a scanner to check things out and found I have 5000psi cranking pressure on the HPFP and about 100psi from the fuel rail sensor. Any ideas how to get this thing started? Is there a ICP sensor I can unplug? Thanks
 
#2 ·
not sure i understand; you have 5000psi cranking pressure, but 100psi frp? where are you reading the 5000psi from?

if your lpfp is making noise, and you have low icp, highly suspect metal debris in the fuel system. usually caused by an hpfp failure. what i'd do is remove the frp sensor, remove the lh fender liner, get a black spray paint can lid, hold it under the rail where the frp sensor was and have someone crank the engine briefly. inspect the fuel for glitter. make sure to use a black container. if you find debris,you'll need to install the contamination kit, filters, flush the lines, drop the tank to drain and clean
 
#3 ·
trust me, went through the same thing. truck came in, failed lpfp. growling and grinding. replaced lpfp, hear whining noise. thought had air entering for sure the way it sounded. turns out the lpfp whine is a dead giveaway for metal debris. checked using that method, had crap loads of shimmer. pulled the hpfp and disassembled, found the cam rollers were desintegrated.
 
#4 ·
Thanks for the fast replies. I will double check things today and report back later this afternoon. I suspected the HPFP but say a glimmer of hope with 5000psi. Main in still in hot water though. I really don't feel up to a cab off ordeal, that's a pita. Low mileage truck too. It did get some bad fuel so this is where it all started
 
#7 ·
commanded fuel rail pressure to start showed 4350PSI, the most I saw was 875psi. Unplugged the GPCM and gave it a shot of break cleaner, fired right up & throttle took over for a bit. I watched the rail pressure slowly drop below 500psi and it died. I guess the HPFP is shot, that's just fantastic.
 
#8 ·
just make sure you get all the debris out. procedure is to drop the tank, flush it, reinstall, add fuel, then disconnect return line at the fuel cooler and run a 3/8" hose off the cooler into drain pan and run the pump to flush out the debris. then install the contamination kit. you can try just doing the pump, but in my experience, the injectors, if not already damaged, will not be far behind. plus the kit's actually pretty cheap compared to individal parts pricing. you will need to program the new injector iqa's though.
you should take a sample from the frp port. see how bad it looks
 
#9 ·
Pulled the fuel rail sensor. There is a trace amount of metallic in the fuel I would have expected more for a HPFP failure. Any chance that came from the LPFP when it failed and I have a bad fuel pressure sensor not allowing injection? Slim chance I'm thinking
 
#10 · (Edited)
did you use a black container to catch the fuel? that is very important as you will really see the metal against the black.
if you disconnect the frp sensor and crank, it should give max pressure. if you get nothing cranking with it disconnected, you aren't building icp.
the frp sensor is in the rail, which is after the hpfp, and, of course, the filters. so it would need to be coming from the hpfp. these hpf systems are extremely sensitive to foreign material. it takes mere microns to cause catastrophic failure to the pump, and injectors
 
#15 ·
Ok, got to ask.. with a 2015, why the heck are you replacing all this yourself when you are under warranty (unless you have rust in the fuel system).
 
#17 ·
Can anyone here enlighten me on why you can't wash out and flush the fuel rails and high pressure lines? Ford says you need to replace them when you have HPFP failure? The kit is quite expensive I'd rather replace just the pump and do a good cleaning on the rest of the system
 
#18 ·
you can try. but you might end up replacing that pump again. plus the rest of the system. if there's debris gone through the injectors, they're likely done or will be soon. not saying it isn't possible. really depends how bad it is
 
  • Like
Reactions: Pro fuzz
#19 ·
It was suggested to me today that I should have a lot more metallic than the minute amount I have for casastrophic HPFP failure and that it's possible what is showing up came from the LPFP. A bad pressure regulator could cause no fuel rail pressure. I noticed today while messing around on the scanner that I could unplug the regulator and it had no affect on my rail pressure at all. I also notice that with the key on and not trying anything that my rail pressure is jumping from 42.1psi to 98.6 back and forth about every 3 seconds. Now I'm lost. Do I have some faulty sensors/regulators?
 
#20 ·
without seeing how much metal was in there, i can't say if it's acceptable or not. the secondary filter should have caught any debris if it were from the lpfp. your frp will jump around a bit between 0 and 150. that's pretty normal. if the hpfp is shot, disconnecting the reg won't make a difference in pressure, since the pcm will command it to shut anyways. not saying it's not the reg. it is possible. post up a clear pic of your sample if you can
 
#24 ·
good news is, that's a great picture.
bad news is, that is not a minute amount. that is definitely not looking good. that fuel, along with the particles in it, are going straight into those injectors.

i'll say this; if that truck came to me, lpfp whining, low icp cranking, that in the fuel, i'm not hesitating to call a contamination kit on it. and i respect the customers money as if it were my own. not saying a pump alone won't get it running. you did say you were able to get it running with ether, so who knows. but i can't see that metal not causing any damage to the injectors
 
#25 ·
think about this; what does a pump cost? 2-3k? what does 8 injectors cost? 2k? that alone is about the cost of the kit. plus you get the reg, frp sensor, rails, supply/return lines, lp switch. i think ford knows that this problem is becoming somewhat slightly common, and is offering the kit at a very reasonable price to try and compensate
 
#27 ·
i would say so. from the info that you've provided.
what you could do is buy the kit, flush the system, install the hpfp, and if that works, buy another hpfp and return the kit complete. if you're gonna do that, i'd probably remove the rails and lines and flush them on the bench as well. when you have the pump out, open it up and have a look at the rollers under the pistons. see how badly the hardening has degraded.
tbh, if it were my truck, the amount of work involved with all that, i would just bite the bullet and install the kit. up to you though. like i said, not saying it won't work, but i wouldn't leave it up to chance
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top