Low rail pressure - nearly stock truck!

[DTL]

My '14 is stock, with the exception of an Innovative SCT tow tune. At WOT, on the 3-4 or 4-5 shift, the truck will lose power and boost and set a low rail pressure code. As soon as I shut off and restart the engine, the problem resolves itself and I'm back to full power. It used to only happen once a month, but now it's a daily occurrence, whenever I go WOT to merge onto the freeway, etc. Do these truck have a fuel rail relief valve, like my old Dmax? I remember a similar condition, that would get progressively worse, with increased rail pressure tunes. Any ideas what's causing this? I'm going to reflash the truck back to stock and see if it keeps happening, but any leads would be appreciated.

Thanks!!

 

[Jacob @ No Limit]

Have the fuel filters been changed recently?

 

[DTL]

Yes, I change them every other oil change. This issue has very specific effects that happens under very specific conditions. It's not one of those "catch-all", "boogyman" problems like you see with clogged fuel filters, where the truck just generally runs like crap.

 

[hunter_.b]

Mine started same thing after innovative tunes. Didn't see it with the pip. Always something

 

[Captaincworley]

Mine is doing it on the Innovative Hot Street Tune as well. Did it twice tonight at the track. I just swapped to the Innovative tunes from the Pip. I ran all the V7 Pip tunes from tow to extreme and never got the code. The 2 passes I made that tripped the code went like this. The 1st time it tripped I staged 1st and started putting a load on the truck to get a good launch. Well the other guy took his sweet time staging and about 3/4way down the track I got a Check engine light with reduce power now. I pulled off to the side after I got off the track and cleared the code. The next pass worked good. The 2nd time it did it, I guess I didn't upshift it like I thought I did and the truck just revved out to 3800rpm before I got it to shift. it started pulling hard then all of a sudden I got the Check engine light along with reduce power now once again. So once again I drove to where I could pull over and cleared the code. I ran the truck hard a few times on the way home and all is was well. I emailed Mike @ No limit about it and he said he was gonna look into it so we shall see what he comes up with. The innovative tunes sure do shift good and pull hard tho

Charles

 

[UpstateDieselGuy]

Your truck may not be able to keep up with the commanded fuel. I haven't had any issues yet, but I know that they have found some trucks HPFP can't keep up.

 

[stevens6.7]

Where does one monitor the Rail Pressure at? Or does it come up on the dash? I don't have the upgrade dash like the Lariat trucks do. I'm fully deleted as well.

 

[jcain]

Without knowing the commanded rail pressure & pulse width, all guesses are just that. Any of you guys having this issue happen to be running large tires and long gears? (35"+ and 3.31?)

 

[Codydiesel]

Nope I'm on 3.31 and 35s with no problems with a 1430 pw tune on a 12 pump and 63 non vgt

 

[Captaincworley]

I'm on a 35" Toyo Mt with 3.31 gears. I never even thought about that being the reason but I'm sure it isn't helping matters. Mine only did it twice and I was stalling on it to build boost pretty good to try and get a good 60ft. I've ran it pretty good on the street just rolling down the road and getting into it with no problems tho.

Charles

 

[jcain]

It's all relative. A 1/4mile is much further than you think. Go mark a 1320' on a secluded street and take a run at it. It'll drain the rail too. Most people never run the street as hard or as long. Brake boosting and dead hooking 4wd is also an added load that'll help drain the rail faster.

 

[DTL]

I put the stock tune back in the truck and all is well. No more codes. I have to say, the transmission is far smoother with the stock tune, as well. I have a hard time believing that the rail is being drained with a "50hp" tow tune. I'm curious if there's something else causing it. I may try someone else's programming. Does anyone have and more suggestions for SCT tuners?

 

[Powerstroke Man 6.4]

I put the stock tune back in the truck and all is well. No more codes. I have to say, the transmission is far smoother with the stock tune, as well. I have a hard time believing that the rail is being drained with a "50hp" tow tune. I'm curious if there's something else causing it. I may try someone else's programming. Does anyone have and more suggestions for SCT tuners?

Are you able to watch actual RP on a monitor?

 

[lincolnlocker]

Where does one monitor the Rail Pressure at? Or does it come up on the dash? I don't have the upgrade dash like the Lariat trucks do. I'm fully deleted as well.

you cant monitor it through the dash even if you have the lcd display. i use the torque app on my phone.

live life full throttle

 

[hunter_.b]

33" tires here. Funny I have been lead to believe I was the only one having issues. Ha

 

[hunter_.b]

Mike a NOLIMIT has been more than helpful sent me a new inovative tune to try, haven't just yet due to rain but will update as soon as I get time.

 

[stevens6.7]

you cant monitor it through the dash even if you have the lcd display. i use the torque app on my phone.

live life full throttle

Oh okay. Well might have to get that app. Thanks man!

 

[lincolnlocker]

Oh okay. Well might have to get that app. Thanks man!

and bluetooth obdII adapter. i have 16 bucks into it all.. i have a thread about it too..

live life full throttle

 

[DTL]

I don't think the SCT x4 can read rail pressure. I'll scroll through the options again though.

 

[DTL]

Bumping this back up for updates! Anybody gotten a tune revision from Innovative? Anybody had good experiences with another tuner on SCT, that they'd like to share??