1991 topkick shuts down while driving.

[scotts dump]

I have a 91 gmc with a 3116cat
All works fine then fast beeping and I loose power to fuel solenoid. Fires right bank up then dies it again after reset. Any ideas?

 

[Coaldust]

Welcome to the HEF! We love a good medium duty, 40 year old, GMC thread. Especially, with 3116 power. It’s been two weeks, or so, since we had a good chat about them.

The fuel solenoid could simply be tired. Is it getting hot? I would put an inductive amp meter on it and watch the draw. Might even pull the valve cover and make sure the fuel linkage isn’t jammed up or a sticky injector rack.

 

[heymccall]

Fast beeping says voltage loss.
I'd start by looking to see if the ignition switch is swelled or deformed, and, whether or not the connector is heat damaged or corroded.
The ignition switch is on the lower column, linkage actuated from the lock cylinder.

If it were the stop solenoid, I'd think that there'd be no accompanying beeping.

 

[scotts dump]

Interesting I did notice low voltage on guage when running 12.5v or so. I though this may be a lazy regulator and or alternator however truck has no problem starting and cranking. Would expect to see 13.5 to 14.5 or so charging voltage. Maybe electronics don't like lower voltage while running. I will definitely check out the ignition switch mounted on the column. Thank you

 

[scotts dump]

When you turn on key you get beep-beep. Crank it, it fires right up 10 to 15 second pause (quiet) then beep-beep -beep (twice as fast as cranking). Truck runs 30 seconds or so then cuts out. Cycle the key and you get another 30 seconds.

 

[heymccall]

Our '07 C7500 will shutdown on low coolant.

 

[scotts dump]

I was told to check that out. Coolant level is ok. Unplug sensor no change short across wires equals no change. ?

 

[Delmer]

Is the fast beep from the brake warning when the electric back up comes on with hydroboost brakes? can you stall the engine to replicate the sound? Thirty seconds sure sounds like an automatic shut off, especially if it's close to exact and consistent. Is there anything aftermarket under the hood?

 

[scotts dump]

Truck has air brakes so no hydro boost. I will check out the alternator with a voltage meter and a carbon pile. Or while beeping I could just set up some jumper cables to a running truck and this should boost voltage. It may just stop the beeping and shut down. I will give it a go and let you know. Thank You All Truck has 118000 on the meter runs good but no powerhouse.