Duramax- Help?

On the way up to Mille lacs last weekend my engine would start stalling out when I was pulling the boat. I pulled over on the shoulder, and put it in park and the engine would not rev over 2000 rpm. So I shut the engine down and restarted it, and it would instantly run past the 2000 rpms. I could then drive for another 50-75 miles and the same thing would happen again. It only happens when I am towing the boat.
Anyone have any Ideas?
Thanks

If there’s no check engine lite that came on, I’d start with the fuel filter.- -jerr

X2 on the fuel filter.

What year???
Wallster ><((((>

It’s going into “Limp” mode if won’t run over 2000 rpm. Are you running a programmer? other mods? ahat year is it?
Was it overloaded?

Some potential reasons…

There are quite a number of factors that will cause the Duramax to go into limp mode. A DTC setting in just about any system can cause a limp mode result.

Here are some common “limp mode” causes:

1. A plugged fuel filter. This will usually cause a P0093 or P1093 DTC. (depending on the model year) The limp mode will be evident after 10 seconds of pulling or accelerating hard, although if it’s really plugged it can cause a limp mode with less fuel demand.

2. An injector terminal fretting problem. This is common on 04-05 LLY engines and generally affects #2 and #7 cylinders although it can affect others. It will set a number of DTC’s. There is an updated 90 degree connector and support brackets for these two injectors that repairs this problem. When it goes into limp mode, the truck will barely crawl and the engine may or may not start. It also will have a loud injector rattle.

3. A leaking-down fuel injector. This will usually set a P0093 or P1093 (as above) and may manifest itself by being hard-starting or long-cranking. A number of other concerns can cause a P0093 or P1093 DTC, so it will require some diagnostics at the dealer to narrow down. The limp mode generally will manifest itself with higher fuel demands, similar to a plugged fuel filter.

Another way to get your duramax into limp mode is to forget to replace the fuel cap, get on a on ramp and give ‘er the beans! Apparently the fuel system doesn’t remain pressurized properly and just when the duramax goes looking for an extra dose of fuel it gets none and gets crabby about it.

I’ve done this one twice. Both times I was refueling in a hard rain and was in a hurry to get back in the cab. My fault for sure. Other than that my 2005 hasn’t had any issues.

My 05 did just what James said #2, this happend while comming home from the lake pulling my boat on monday.
Wallster ><((((>

If it happens while driving, a injector leaking down, is not likely the culprit, but definitely sounds like a fuel issue. I am not totally familiar with a Duramax, but it could be what is called the pick up pump… this pump pulls fuel from the tank and supplys to the high pressure pump for the engine. It could be getting weak and when it gets hot, after driving awhile, performance is compromised and fuel is starved, causing the chugging/hesitation and throwing in limp in. I would definitely lean towards a fuel issue and not electrical. Typically, a true misfire will not cause a vehicle to go into limp in either…. there are only some many things, by law, that can allow limp in, as it can become a liability if you need to go faster than 30 mph… Limp in is something designed to save you from causing more damage to your engine or transmission, unknowingly.

big G

This is a 2001 GMC with approximatley 160,000 on the truck. I have had the fuel filter replaced about 10,000 miles ago,and have kept the factory recomended fluid changes, and maintenance as scheduled.

What confuses me is that when I shut it down and then start it up again it runs fine,and the only time it happens is when I am towing the boat. The sevice Engine soon light comes on and does not go away while driving, but if I park it overnight and drive it the next day it runs like a top.

I guess I will have to take it in for service.

Thanks for the Ideas, it will help me to pin down what is happening with my dealership.

The reason shutting it down works, is because it is resetting the limp mode, and it will work fine until the conditions are repeated and it goes into limp again. A little free advice for someone having drivabilty issues. Pull over where it its safe…shut the vehicle off and restart. This fixes more things, or at least resets the modules so vehicle can be operated normally, until you can get repaired. To take it a step further, disconnecting the battery positive cable for 10 minutes, will also reset most modules Some things you can try in an emergency.

big G

If the engine light is on, stop by a parts store. You can use there code scanner for free.

OUCH!!!!!
$831.79….. Fuel rail Pressure sensor

Thanks for the information guys
I was a little apprehensive about it being the fuel system.

Quote:

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OUCH!!!!!
$831.79….. Fuel rail Pressure sensor

Thanks for the information guys
I was a little apprehensive about it being the fuel system.

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$831.79………doesn’t surprise me, I own three diesels. When they break, fixing them breaks the bank!!

James, you know far to many codes for just having gotten that truck.