Duramax losing power - Montana Owners Club

NCFischers · 08-06-2010, 09:54 AM

My '03 Duramax lost power today. I pulled away from a light and could only get 2000 RPM from the engine. I pulled over to the side of the road and floored the accelerator. Tach only went to 2000. I let it idle for a couple of minutes and floored it again. This time RMP's went to 2300. A few more minutes, did it again and it went to 2700, then 3000. Finally, I could red line the tach. Drove it to my mechanic and he now has it on the diagnostic computer. Anyone have this problem?? So far, we're at a loss.
On edit:
Diagnostics showed nothing and there are no service bulletins on it. He did find that both the batteries (Exide) were weak under load, one was starting to boil over and one cable connection was a bit loose. They are only 2 years old. New Interstate batteries to be installed Monday.

SlickWillie · 08-06-2010, 11:43 AM

If it had stayed at 2000 RPM, I would say "limp mode". But, IIRC, it won't gradually increase in RPM when in limp mode. Sounds like a fuel issue to me.

Just out of curiosity, did the tech say what the flow rates on the injectors looked like? I've never noticed where you mentioned having them changed. Pretty long injector life for a LB7 engine. Not saying that is the issue here. You'll notice smoke and gradual loss of power when they start going.

skypilot · 08-06-2010, 12:12 PM

I agree - sounds like a fuel filter problem.

NCFischers · 08-06-2010, 12:15 PM

Will,
The truck has just a bit over 100K on it. The injectors have never been changed. No smoke issue even when I accelerate rapidly to pass someone without the trailer. My mechanic didn't mention the flow rates but I'll ask him on Monday. He just changed the fuel filter and I just cleaned the air filter.
Jim

Mudchief · 08-06-2010, 04:41 PM

Jim, most likely the fuel filter. 2000 rpm means you are in the limp mode. When that happens you can turn the engine off and let it sit for a few minutes then the computer will reset it and it will run ok until you get on it again. When my fuel filter gets dirty the truck will do that every time. I don't go anywhere without a spare filter.

lasater · 08-06-2010, 05:11 PM

2 days ago, I was pulling the Monty over the Bighorn mountains in northern Wyoming between Buffalo and Thermopolis. I lost power. during a hard pull. After a short idle period, power came back so, I thought...fuel starvation. 15 minutes later, it did the same thing. This time, I stopped, pulled out my OBD II reader and plugged in. I got a code of P-0299, Low Turbo Pressure. I eased it on into Thermopolis. Just as I was approaching the Fountain of Youth RV Park, the MIL lit up. I took another reading and had 2 codes of the same. After babying it on in to Hill AFB, UT, I took it into a Dodge dealer this morning. The tech checked it out and said that all that was necessary was to re-flash the computer. It seems this is not an isolated problem. They have a fix for it but they are not doing a general recall.

The RAM is running fine, now. I just hope that re-flashing also improves the mileage. That would make the worrying I did worthwhile.

NCFischers · 08-06-2010, 05:18 PM

After doing some reading on the Duramax Forum, I believe the truck went into limp mode. After the computer reset itself, the truck runs fine. I'll keep an eye on it for the next few days. The big test will be next Wednesday when we head to the Mid-Atlantic Rally. One more thing to be thinking about while towing.

SlickWillie · 08-07-2010, 03:43 AM

Quote:

quote:Originally posted by NCFischers

After doing some reading on the Duramax Forum, I believe the truck went into limp mode. After the computer reset itself, the truck runs fine. I'll keep an eye on it for the next few days. The big test will be next Wednesday when we head to the Mid-Atlantic Rally. One more thing to be thinking about while towing.

Jim, the 2000 RPM sounds like limp mode, but I was of the impression you had to turn the ignition off for a few seconds to reset the ECM. I would have thought you would have codes stored also if it went into limp mode.

NCFischers · 08-07-2010, 06:16 AM

I did turn the ignition off but just briefly. No codes showed up when diagnosed.

Art-n-Marge · 08-07-2010, 07:01 AM

If a device needs to be reflashed I hope it's because the "software" is corrupted. Otherwise they are hiding the root of the problem and hoping it does not happen again. What caused that in the first place? If they just reflash the device, this doesn't imply what caused the device to "lose its brains" like it did. I hope they "dumped the flash" for some engineer to review, but I doubt that.

Who knows when or where this might happen again since it doesn't appear they found the "root cause". I was in Quality test and control for over 33 years. I've been "trained" to recognize when a root cause has been fixed, or a problem has been fixed temporarily. It does not appear the problem was fixed. If you're lucky you won't see it again, but I hope your Dodge does not turn into a Toyota (note they tried to sweep their problems under a rug instead of looking for the root cause).

I had a friend where the dealer kept pulling crap like this on him. He and I bought the same '04 Ford 3/4 tons within months of each other, but his was giving him fits. He was a manager of mine in the Quality Engineering field and us problem-solving experts are driven nuts when working with dealerships who think "Slap and go" is how to treat a customer. He eventually lost confidence in them and the truck and downgraded to a Nissan 1/2 ton. Fortunately his trailer and boat are okay with that TV.

Best of luck to you and stay safe!

thor · 08-07-2010, 05:45 PM

i have a 2003 duramax .sounds like a fuel filter to me.it went from 2000 rpms then sat then went to 2700rpms .sounds like the filter was getting plugged then fuel filled back with time .when was the last time the filter was changed?

camper4 · 08-08-2010, 12:00 AM

I've lost power twice and both times I needed dealer help. Once it was a computer reboot and the second time it was low fuel pressure requiring fuel and air filter changes.
I did have a third time, right after fueling up at a truck stop, the engine ran rough but had power. After a few minutes of running it was fine. I suspect that was a fuel problem.

NCFischers · 08-08-2010, 01:11 AM

The fuel filter was changed a couple of months ago and I just cleaned the air filter. Since then, I've only filled up at my local Hess station where I buy all my fuel when I'm not on the road.

Exnavydiver · 08-08-2010, 05:21 AM

Jim, go buy another filter anyway. This whole evolution is a carbon copy of my problem and a new filter fixed it. Try all the simple things first. My filter was only in the 50% range and when I dumped it out is had a load of trash in it. Even if you got good fuel a thousand times in the past there is a chance that he got dirty fuel this time from his distributor.I got a WIX filter this time around. It was about 41 bucks at the local independent parts store... Dave

Tom S. · 08-09-2010, 09:55 AM

Quote:

quote:Originally posted by NCFischers

Will,
The truck has just a bit over 100K on it. The injectors have never been changed. No smoke issue even when I accelerate rapidly to pass someone without the trailer. My mechanic didn't mention the flow rates but I'll ask him on Monday. He just changed the fuel filter and I just cleaned the air filter.
Jim

I hope that doesn't mean what I think it does.

NCFischers · 08-09-2010, 11:49 AM

Tom,
I have a K&N air filter and I cleaned it about 3 weeks ago.
Jim

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