Need help from you again, limp mode?

[fasterthanyou]

Thanks for looking at this thread. I really need your input on a problem I'm having with my truck. I posted a thread about limp mode a couple weeks ago while towing with the juice box on level 4. The truck looses almost all power, suddenly, and you can just get to the shoulder and stop for a few seconds and then it is fine. It has done this towing once on level 4, and now not towing 4 times on level 4. The truck has almost 90k on it, hard,hard miles, but has been maintained to the specs required. I have bought fuel all around and it has nothing to do with this, every time it has been at about 80mph on level ground just cruising along. I'm leaving for a 2500 mile trip Tue night and would really appreciate any suggestions, tranny going south, injectors cloged etc before the trip. Thanks guys, you are the authority on these trucks!

[Pizza Man]

Why do you use a juice if your pulling a trailer? And on the towing subject why did you lift the truck? And why did you put bigger tires on the truck. In my opion Gm trucks are all set for towing stock (except for trailer hitch). I would take the chip out and lower truck back to stock and put the stock tires back on.

[PEANUTGRWR]

FASTER, WE HAVE HAD ONE OF OUR TRUCKS DO THIS EXACT SAME THING. AND THE PROBLEM WAS THE FUEL FILTER WAS PLUGGED. WHY DONT YOU CHANGE IT AND SEE IF THAT HELPS. JUST MY TWO CENTAVOS WORTH

[mackin]

FTY

Are you throwing a SES??? If not, probaby not limp.....
I'm with Peanut change the fuel filter first.....
Got gauges???
What and how much are you towing in level 4???
I thought limp mode wouldn't idle it self out more like you had to shut it off for a bit?? You imply a few seconds as if you never shut it down.....I'm leaning to the F/F....

Good luck...

MAC

[ 10-06-2002: Message edited by: mackin ]</p>

[FirstDiesel]

The first thing I would do is change the fuel filter. The 2nd thing I would do is stop towing in level 4.

[MAD-MAX]

Mine did the same thing was the fuel filter both times...
P.S. nothing wrong with towing in level 4 as long as ya keep a eye on the pyrometer..
Yep don,t know why anyone would like to soup up there D-MAX :D :D :D :D

[FirstDiesel]

Provided you have gauges and provided your not having any other problems occuring.

[GBurton]

Let's see if I understand you correctly. You are complaining about a problem while towing with the Juice box set to level 4. From reading posts on here and reading a friend's Juice manual the people who designed the Juice box clearly state to use ONLY level 1 or 2 when towing. Do you know more about the Juice box than Aaron at Edge? :(

George

[motovet]

Why tow with the Juice? Because it is better in every way! With all the talk of 1/4 mi. times, launching in 4x4,and tires roasting, some may have lost sight of the benefits the Juice brings to towing. Don't get me wrong, I LOVE the new SUPER level for solo cruising,but as good as the Juice is for bad driving habits, it is even better for towing. Holds a higher gear in every situation, reduces shifting, added passing power, and slightly improved MPG's.
You can run higher levels than 2 if the load isn't to heavy and you take it mellow... but watch those guages! You will know if there is to much power for the load cause it WILL go limp. Tranny upgrades should fix all that.I agree the stock tires would deliver the best performance , but they look like sh$#.

[XAM-D]

Fasterthanyou,
What kind of mods did you make to put air lift bags on with a 6" lift. Did you have to have blocks made. Why, Air Lift bags and Firestone compressor?

[fasterthanyou]

Thanks for your input,
I'm not towing in level 4 anymore, that was just the first time I had problem. I am driving solo in level 4 and having the problem. The trailer is heavy, 15k, but everything else is ok with the truck. You can be crusing down the highway with the flow of traffic, 80mph around here, and suddenly the power is gone and your looking for the shoulder. I let it idle for 1 min, and away it went, like new. About towing with the juice, I would have ditched this truck and got a manual if the juice didn't come out. It only towed in 4th gear before the fixed GM's mistake.

[Jim Rokon]

Fore what it's worth, I have only had my Duramax shut down to an idle once, and that was after I installed the Juice, put it on #4, left my driveway and SLOWLY drove uphill from my house. The truck just dropped to idle and I had to stop and turn the Juice off (select trans. into R) to get going. I figured it had to do with not getting the water temp up to where the Juice wants it to be. Was that a correct diagnosis?

[hoot]

I believe your problem is the computer is backing the power down. I noticed this the first time I towed, way before I made any changes to the truck. As time and miles accumulated, it was only backing down at about 80 mph or so, when on propane. No one seemed to have a clue as to what I was experiencing. I first thought it was a tranny issue but I was dead wrong.

For some reason, since it has broken in and had all the computer updates, I haven't had anything unusual happen at all.

Make sure you have all the latest updates. I don't believe you have a serious problem on your hands.

[fasterthanyou]

Thanks for your help all!
I'm going to change the fuel filter today and cross my fingers. I thought it was the tranny cause it would only do it in fifth, and from what i've read, that is the only gear that slips with the Allison. The Juice is one of the very early boxes, low 3.xx numbers. I dismissed the fuel filter as a problem, cause you could pin it from a dead stop to the speed limiter and it would'nt starve for fuel. I know a thing or two bout gas, but nothing about diesel, and I assumed a cloged filter would show its problems on full throttle assults more than light cruz'n. Hopefully I'll make it to NM on time, thanks for your help, I leave tue night.

[Pizza Man]

I would not pull a 15k trailer with your truck the way you have it set up. I think its not safe.
Take the lift out! And go back to stock tires.
As far as the juice goes, I just don't understand why you would buy a truck for towing then mess with the computer on it. I would be scared that any non oem part I installed would cause problems...and apparently it has.

If you are really pulling a 15k trailer put the truck back to stock.

If you have any doubts, there are many "trailer haulers" on TDP that will confirm what I said about pulling a 15k trailer with a lifted truck and big tires.

[ 10-07-2002: Message edited by: Pizza Man ]</p>

[Swayse]

Do not use your truck for any enjoyment. Take out any radio or CB, we need you to keep your mind on your driving. And if you drive a dark colored truck, you need to paint it a light color now, so we can see you better. Where in the world do you think we live, America? :D :D :D :D :D

[motovet]

Yes, I agree. Middle age (20-70) is not playtime. The monthly payment should be plenty exciting for you. And about that YZ young man...

[fasterthanyou]

Thanks for all your help Pizza Man. I'm sure that kind of advice is why the other members use this website. Hope you don't get in front of me in my big unsafe truck, I might not be able to stop! I guess i'll just have to make a pass and blow some diesel in your pie.

[Kennedy]

I'd agree on the fuel filter as first issue, as well as air filter and/or loose foil dingus blocking the filter.

Additionally, there are also a whole slew of PCM and TCM updates that COULD be related. The major ones being correction for false trouble codes. Is the SES light coming on?

[fasterthanyou]

Thanks Kennedy,
I changed the fuel filter and still had the problem twice today, both times same as before. NO trouble lights have come on the display. Today I tried to punch it when it lost power, it still slowed down, like a carb would do when it is out of gas and you have to switch tanks. (that was the last truck) Then I lifted the throttle for about 10 seconds and rolled into it and it was fine. It would shake coming on and off the power at .25 throttle at 50 mph. I lifted again for about 10 seconds and hit tow/haul mode. Couldn't get it to duplicate the problem again in tow/haul. My Juice is set at level 4 in regular and level 2 in tow/haul. Is there any kind of overfueling/boost limiters built in to the truck? That is what it feels like. I would love to get to the bottom of it. I will take my truck in next week and get the latest updates and send my early model Juice back and get it updated. Is it possible my Tranny is slipping even though I don't feel it? Could this be limp mode?

[hoot]

That is exactly what mine did on propane once in a while. I'd hit 80 or so and the power would just drop to zero. I'd let off and coast a bit, while testing the throttle. Finally it would come back. Sorry I can't help cause mine doesn't do it any more. It stopped doing it even before I had the updates done. No explanation.

[Kennedy]

Have you tried it w/o the Juice? As a process of elimination, I'd remove any aftermarket devices to see if it still occurs.

Something we really haven't seen much of has been electronic injection failures. It looks like these systems are going to be pretty darn stout, but I think there could be definite potential for such a failure.

[Brandenburg]

fasterthanyou, what you just described is what my truck will do when it rains. I've thought that it was juice related but I really can't tell because there isn't any low end throttle respone stock at 1/4 pedal, you have to push it more to get any acceleration and then it downshifts.

Now my father's truck, which is also a 2001, has never done this and he has the juice as well.

[ 10-09-2002: Message edited by: Brandenburg ]</p>

[fasterthanyou]

Hey guys,
Just got home from a bad weekend of having fun. Had a blast at the Supercrawl, but got my butt kicked. (rolled over on day one, broke a rear axle day two, and a tie rod, and an carrier later on) Just wanted you to know that I set the juice in tow/haul mode 1 and had zero problems with the power going away. I threw a check enging light in flagstaff, AZ and it cleared itself the next day. Then I threw a check enging light in Farmington, NM on the way home and it is still there. Hauled as* home, as usuall, and never had a problem with the power going away. I'll get the truck to the shop this week and get the updates per your advice. Thanks for your help. Your a great resource of knowlege and a good group of people.

[blue]

My truck has the same occasional limp-home episodes.
I have Juice V3.5, and towed my enclosed carhauler to Texas and back on Level 2. It did it once on the way down to TX, and at least 20 times on the way home. Here is what happens:
Driving under ANY throttle condition (uphill, cruising OR DOWNHILL/COASTING it will powerdown.
You can feel the truck "juggling" the power, surging a bit, then it can go into a "rrUUM rrrUUM rrrUUMM" type revving (in cruise control)and I thought it might be the TRANSMISSION thinking about downshifting but NOT completing it.
It THEN goes into limp mode, where rpm can't go over 2,000; power is low; and floor throttle below 2000 causes a downshift and SLOWS the truck because in LOWER gear, 2000rpm gives SLOWER speed!

I figured the pattern out--I had to let it just coast down to rpm around 1500-1800, then apply a little throttle, and it would UPSHIFT to a lower rpm/higher gear (lugs down some) and suddenly ALL FINE AGAIN! Could INSTANTLY floor it to MAX, including UP TO LEVEL 4 JUICE, and NO problems...until the NEXT _RANDOM_ time the "limp home episode" happened again.

Limp home would last between 5 seconds and 20 seconds...basically, trying to keep throttle floored kept it in lower gears/higher rpm which delayed it getting below ~1500rpm so delayed its "resetting" itself. Switching between level 2 or 4 did not seem to change matters. It was NOT RELATED TO WHAT POWER I WAS USING, seemed RANDOM.
I have 30,000 miles on truck and haven't changed fuel filter yet, but it looks like filter did NOT solve it for Fasterthanyou. I will change the filter anyway.

The truck has had a "Service Engine Soon" light since these episodes started happening on the trip, and still has it now, so something must be unhappy in the ECU computer, some flag getting to critical and resetting. Can I find out what that code is MYSELF or do I have to get a tool or go to dealer?
Do the newer Juice updates have this or FIX it?!?

[ 10-14-2002: Message edited by: blue ]</p>

[fasterthanyou]

Hey Blue,
Just wanted you to know that after reading your post, I'm a little more calm when the motor cuts out. You are very good at noticing when and where the engine still makes power. I kept forcing the downshift and that would make the power go away again. I sent my Juice box back to Edge and they updated it to 4.61. I drove all over without the juice, very boring, and didn't have a single problem. I put the new juice on last night and had the same problem on level 4. It will not do this on level 2 or without the juice, but randomly shuts off power while crusing at 80mph on level 4. I must say that the hot juice is great. Real power, real responsive. I have noticed a weird shifting pattern some times at 3/4 throttle where the motor revs up between shifts on tow/haul level 4. I would like to see if anyone has any final thoughts on what to do next to keep this truck from loosing power unexpectedly. Thanks again.