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Discussion Starter · #1 ·
When towing, or heavily laden with the in box camper, if I take my turbo boost above 30 psi, I tend to get a code, telling me I have low fuel rail pressure. With my Mini Max, I delete the code, the only reason for doing so is that with that particular code (there may be others) my cruise control won't work with the remaining code. All is good again once the code is deleted! Or that is, until the next time I push the truck above 30 psi for a good length of time.
I don't know 'why' this is an issue, as the truck never falters when the code is set, it just sets a code. I don't know if it would make any difference, but to date my Mini Max is always set on the 'Wild' setting, so perhaps I should try the stock setting, but I can't see it making a difference?
Not being fully understanding of the 6.4's fuel system, but could it be the 'fuel pump' itself? I'd just like to understand why this situation occurs, and why it may be so, otherwise the truck runs like a champ!
Just did a 10.200 kilometre trip from the U.S. Canada border up through the Yukon and Alaska in August, and the above situation was the only issue I came across! The only way I know a code is set...is my cruise control is unusable when there is a code set. Thankfully, a quick stop...do the delete and all is good again!
Headed up the Alaska Highway again, getting home last week from our annual hunting trip, and again, this happened twice, as I was pulling a heavily laden enclosed trailer.
The truck doesn't get much use, other than for hauling purposes, so getting a better understanding of this issue would be appreciated!

Thanks in advance for any advice/comments/options!
 

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There are a lot of things here...

First, there is an update for this.. Gotta get a dealer to flash it... It didn't 'fix' it, though, it just widened the parameter to accept more fluctuation. So.. it's up to you.

Second: fuel filters!!! Make sure and change the things no less than every 10k miles.. that said, always have some extras onboard... You never know when you'll need them from either bad fuel or gelling in cold weather. Filters will limit flow when dirty, and cause what you're seeing.

Third: don't tow on wild!!! By the way, wild was discarded long ago.. you need to update that thing. Your problem may disappear with that... Don't tow in anything above tow in any of the three families of tune.

Fourth: check filters for shards of metal!!! Will indicate if your hpfp is failing. If it is, get rid of that truck, or be prepared to shell out about $5k for fix.

Fifth: if everything is good up to this point, consider a better lift pump and better filtration. Airdog, fass, fuel labs all make good systems. They'll cost around $800 or so, but you'll be able to filter mucho better, and it's unlikely your upper bowl will ever 'run out of fuel' again... If that is contributing, that is. I run an airdog150 and won't consider another product, but that's just me.. excess fuel goes back to the tank, as it does with the hfcm, but more is shoved to the upper bowl, which is what feeds the hpfp, which means it's less likely to run out in high load circumstances. Running out is BAD, and in my opinion at least tied with bad fuel for hpfp failure.. the hpfp's purpose is to pump fuel to the rail from 4800psi (idle) to 25k+ psi at wide open throttle... But. the hpfp uses fuel to lubricate itself and to cool it. When there is no excess, guess what? It gets hot, and it doesn't lube... Both will kill it with a quickness...

As an extra, and VERY common with issues like you're 'splaining, is very simple: check the level of your fuel coolers coolant.. often times, people forget about those things.. and when they do, the first thing they experience is a p0087,.p0088, p0192 or p0193 code... Why? Hot fuel expands, and expanded fuel compresses, poof, loss of expected pressure... It uses gold coolant just like your main cooling system does.

Report back!!! Later....
 

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Discussion Starter · #3 ·
Thanks for the post! I change my fuel filters every second oil change, or since I'm on an extended filter regime with full synthetic, it's 'every' oil change. I've 'never' seen any kind of moisture when draining the filter reservoir, and my filters look basically new when pulled out, but get changed anyway. The talk...some time ago, with the Mini Maxx, was that you get your best fuel mileage on the highest setting, which is why I do so. I constantly monitor my EGT's and all other pertinent info while on the road (my truck is used mainly for vacation purposes) and has never faltered even when a code is set.
Could you explain where the 'check' is for the fuel coolers? Is it under pressure, as if checking it, it's good to know if it's going to spill out! I did just have my coolant changed in the spring, albeit I don't remember them saying anything about checking the fuel cooler coolant? It was a Diesel Shop that did the work as well. They did use the Gold coolant, just as I did the previous time.

Overall, truck runs like a champ...but I will try to run on the stock program the next time I run loaded. Thanks.
 

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the fuel cooler is on a separate system from the main cooling.. there is a reservoir in front of your booster and aside your degas that is black and has the cap that is akin toa radiator cap on a car... it has a little glass window on the front of it, but it is useless. basically, pop the cap with the truck off and fill it up with gold coolant.

unloaded, you absolutely get better mileage on street or performance (hot and wild for older software versions)... loaded, it just isn't worth the risk of floating a head with all that pressure...
 

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PS2000,
Thought I'd mentioned this once before--had the same symptoms on my '09 (which unfortunately died at 207k miles)--cruise would shut off, and throw a code on fuel pressure, but can't remember the code number. Had the LPFP replaced and the problem disappeared. Code was poss P0087 or something close to that.
Joe
 
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