Cold temps / 2000rpm low fuel rail pressure limp

[Mark Rinker]

-12 this morning, truck #3 started fine and ran well initially - but then RPMs dropped and were limited to 2K and limited upshifts as a result. SES illuminated. Tried cycling ignition after truck/tranny warm, code wouldn't clear. Hmmm...usually the LBZ limp on super cold mornings will clear up after awhile...this one didn't seem like a fuel filter plugging, either.

Fuel filter is nearly new <1000miles, already had a tank of pre-treated fuel, so had to stop by a buddies shop (Sunday 5AM!) for a plowtruck tire fix and he offers to throw the scan tool on it before we summarily waste a new filter. Low Fuel Rail Pressure...reset code...back to normal. We'll see if it repeats at next cold startup. Glad I didn't waste a good fuel filter on this one. Ahhh for the "good old days" :) of the LB7s that ran until they plugged on days like this...no SES...no limp...

Anyone else see this? Our other '06 (#1) plowed and ran fine all morning in the same temps, same fuel, same Delco filter change on the same day...weird.

Also - can you believe the luck of picking up a nail while plowing on the coldest morning of the season? Nothing like a tire swap at 4AM and -12 to wake a guy up...yes I was crabby and the driver told me as much...:cool:

[Mark Rinker]

Truck sat all day in subzero temps - off the plug, started fine, warmed up fine, no repeat of code or RPM limit, temps -8.

Clearly no filter issue, clearing the code seems to have solved the problem based on tonights unscientific test. Truck is plugged in tonight...we'll see what tommorrow brings...

On another note, ran a skidsteer tire off the bead in these subzero temps. Two tire issues today - the Bobcat tire is so heavy and hard to manage when this cold...got it warmed up, used a 2" tow strap to compress and pounded it back to contact and got it to seat. Fighting the cold...Minnesota style...goodnight!

http://www.thedieselpageforums.com/tdpforum/showthread.php?p=247446#post247446

[Shed]

<Mark, Sounds like one of my "lucky" nights! Just makes life interesting don't it? What happend to your 01'?

Problem with my truck this a.m. Sounds similar to your problem. Temps -8 with -30 windchill. Ran yesterday, filled with fuel and treatment (been running treatment for a month), plugged in overnight, winter cover on. Started fine to warm up for 15 mins. Got in and drove about 1.5 miles to the interstate taking it easy to warm her up. As I accelerated she hit the wall. Would not go over about 1500RPM and chugged. Once I got out of the pedal it seemed fine. She would idle all day if I let her, but no power. SES light came on after about 4 mins. of this condition. I have not checked the code yet.

I limped her home and dumped a quart of PS911 into her and let her idle for about 45 mins. I took off in the rice burner for work. So whats your opinion? Gelled and not clogged? New Filter (only has 4k on it)? More treatment per tank? What code should I see if it is just gelled?

Thanks for your imput Mark, I like talking to you because your weather is similar (but even colder) to mine. Hope your days get better! Shed

[Mark Rinker]

If your truck is an '01 LB7, I would guess you have water frozen in your filter element, restricting flow.

Check the code - see if its fuel rail pressure related. You might be able to clear it and get back to normal, but my experience with the LB7s is that the filter is the culprit if you are losing power - not the ECM. On my LBZ, the ECM is the culprit first, then the actual filter...

Remember, miles on the filter isn't really relative - its all about fuel quality. All it takes is one tank in this weather - and it may not even be the tank you currently have on board! The filter separates water, and when it gets cold, that water left in the filter, freezes.

[Shed]

Thanks for the advice Mark.

I'm completely clogged now, the quart of 911 did'nt clear up anything. I'm going have her towed to the dealer and have the filter swaped. I'm not sitting out on the driveway in this weather! Have yet to be able to check the code.

When I filled up yesterday it was cold like today (-4) and extremely windy at the pump, it seemed like the hose was frozen and the pump was just crawling. Could this have anything to do with my condition? Sorry to hijack your thread. Thank you again!

Shed

[Mark Rinker]

Can you get it inside, and some heat directed under the front? I hate to see you pay a tow bill!

It doesn't take much to correct this problem...even temporarily until you can drive it to service. Also...do you now anyone with a handheld LB7 power programmer by DiabloSport or Tech II Scan Tool? You may be able to check and then clear the code and get it to shape up...although my guess is your filter is frozen, by your description and the LB7 behavior I have seen under similar conditions. The 'chugging' you describe is the key - indicating true fuel restriction/starvation. My LBZ is simply rev-limited at 2K rpms, if you request more with your right foot, it drops fuel altogether, but no starvation or 'chugging' behavior, its smooth and runs fine to exactly 2K rpm and no more, no less...

If you have a shed or garage and a bullet style heater, place it well back from the truck (3' to 5' away, no closer!) on the ground and direct it straight under the bumper of the truck. Place some cardboard on the floor in an 'L' shape, directing the heat upwards at the firewall. Keep the hood almost shut, but on the first latch so hot air can rise around the engine, and escape from the top slowly. Also, plug in the block heater.

After 15 mintues or so, pop the hood and see if you can feel heat making its way up from beneath, finding its way into the open spaces (occupied by fuel filter) at the rear and sides of the engine. If its working, leave the hood on first latch and let it heat for 30-45 minutes.

Or...one thing I have always wanted to try, but never have - take a hair blowdryer directly to the filter element for 15 minutes...maybe that would thaw out the frozen water long enough to drive it to service? If that doesn't do it, then you might need the tow...or at least a friend to help replace the fuel filter...!!!

*** DISCLAIMER: THESE EMERGENCY HEATING METHODS ARE THE OPINIONS OF MYSELF ONLY - AND NOT THOSE OF THE DIESEL PAGE, ITS OWNERS, ETC... SO IF YOU LIGHT YOUR TRUCK (OR HOUSE) ON FIRE, DON'T COMPLAIN TO JIM (MORE POWER)...ALTERNATELY, YOU CAN SUE ME...BUT THERE ISN'T ANY MONEY... :o ***