1998 GMC 6500 Stalling after 200-300 miles

[illusionaudio]

My 1998 GMC 6500 stalls out periodically after about 200-300 miles. You have to sit there for about 20 minutes then it starts up like nothing happened. It tends to happen around hills. It spent 6 hours in a cat dealer today and they could not find the problem. Right before it stalls teh check engine light comes on. They hooked it to the computer and even drove it with a laptop in it with no results. They supposedly checked the injectors, and fuel pressure. It is a cat 3126. Any ideas? I was thinking maybe the governor? Any way to bypass the governor?
Thanks, Chris in Cleveland

 

[Weave]

With the check engine light coming on before it is stalling, it probably isn't actually stalling, the computer is shutting the engine down on purpose as one of the operating perimeters is being exceeded. This can be a number of things, but whatever it is, if that check engine light came on, there will most definitely be a trouble code stored in the computer as for the reason why it came on. I don't know how the CAT copmputers work, but by pressing a dash button for my Detroit engine, the check engine light will flash the current trouble codes, and another light the stored codes. I find it hard to believe the dealer hooked it to the computer and it showed nothing. It does not sound like a governor problem, and again the computer serves as the governor also. Some of the perimeters that will activate a shutdown sequence are low coolant level, high coolant temperature, low oil pressure, high turbo boost pressure, etc- basically the things that could cause serious engine damage. Sometimes the sensors on the engine for these become faulty, causing the engine to shut down when there isn't really a problem.
Have you tried the simple things first such as replacing the fuel filters and air filter? Is the engine getting too hot when climbing hills?
-Weave-

 

[illusionaudio]

The truck just got serviced last Friday. I bought the truck last Wednesday. It was on its maiden voyage when this happened. The truck it not getting hot and there are no codes in the computer. The problem is there is no for sure way to duplicate the problem, it just happens. Could it have anything to do with hills?

 

[Sterling_owner]

Just wondering what dealer did you take it too?

2 1999 Sterling Semis
2000 Ford F650 24ft box truck
Now hiring driver in Cleveland, Ohio area.

 

[illusionaudio]

Well it broke down in PA so it was Cleveland brothers In Howard , Pa.

 

[Weave]

Was the truck sitting around for a while before it was bought? This relates to the hills. If so, it is possible there is a lot of sediment at the bottom of the fuel tanks which is blocking the fuel pickups and causing fuel system to loose pressure. The hills can aggravate this situation. If the truck has not been used for a while, the tanks should be flushed clean, most often there is a drain plug under the tanks for this purpose. If they haven't been flushed since 1998, I'm sure they are due. When the engine stalls, does it take a lot of cranking to get it to start again? If so, it is re-priming the system due to air being there from loss of fuel. I'm just taking stabs here, your perticular problem can be a lot of things, I'm just trying to concentrate on problems related to hills.
-Weave-

 

[Jimmy]

Hey,
Read about your problem.Does your 3126 have a hand primer pump located above the fuel filter? If it does have it checked to see if the seals are holding in it. Also check under the cab for a small in-line fuel filter. My freightliner had one it got stopped up caused problem similar to yours but no check engine light came on. I replaced the line & the filter with a auxillary filter mounted on the side of the frame. hope this helps good luck with it.
Jimmy

 

[Weave]

That is what is confusing me most on this problem is the check engine light. If it is coming on in illusionaudio's truck for low fuel system pressure for any reason, that active code should be in the computer as it does sound like a fuel starving problem. Oh well, I've seen stranger unexplained things
-Weave-

 

[illusionaudio]

Thanks guys, when he gets back I will try to drain the tank. The fuel filter should have been changed when they serviced it. It seems as if it is starving for feul because it will just crank. Also you can tell when it is going to start because it starts to shake more right before it starts. My guy just called me and he went 500 miles last night with no problem. Hopefully it was just some bad gas or something. On another note I run for a freight broker and because my truck broke down and the load is WAY late, he said that I would get charged for the load $1600. This doesn't sound right and I have never had this happen before. Oh well????