I've posted about this problem on the forum before, but now I have some additional, definitive information. This problem has been going on for almost a year and nothing I've tried to fix it has been successful. At first I thought it was the tranny and had that looked at, including replacing the govenor solenoid. Fuel filter has been changed twice and it's always been OK. I've cleaned the electrical connections that control the injectors and applied dielectric grease. I've checked the wiring harness referred to in the sticky note at the top of this forum about a shorted wire; no breaks were found, but I indvidually taped each wire and put plastic loom around the three wires.

The sudden power loss ALWAYS happens when the temp rises above 200*, but it doesn't happen EVERY time the temp goes over 200*. I assume the system then calls for the fan to kick in or increase it's cooling function. At any rate, just as the power loss occurs, or right after, the temp falls below 200*. It's happened on a slight downhill grade without acceleration when the temp was above 200*. With a cool engine, and hard acceleration, I can't induce a power loss. From that I believe it is not a lift pump issue. At least not yet.

This is a very sudden but momentary event. When it occurs it shakes the truck pretty good. If I'm towing our 5th wheel trailer it's nerve racking. My biggest concern is how these sudden jolts will affect the drive train.

So, what in the cooling system could cause a fuel interruption? Forgive my ignorance here, but could it be the fan clutch? Is there any way it could affect the cam position sensor and temporarily stop fuel flow? Maybe the ECM? (hope not) Would putting in a higher temperature thermostat at least get rid of the symptom even if it didn't cure the problem?

This thing really has me (and a couple of mechanics) puzzled. Anyone got any ideas?

 

Do you have gauges? I had a similar problem with my first 06. It ended up being the air filter. The ecm was not seeing enough airflow and dumping the boost. might not be your problem, but a thought.

 

Nope, sorry no guages. I replaced the stock air filter with a K&N, but I don't remember the date. I'll check my maintenance records to see how that coincides with when the problem started. Thanks for the response. Keepem' coming!!

 

Have You Checked Your Cam Sensor And Crank Sensor For A Short.

 

I think this would have some real possibilities but, quite frankly, I have no idea where these are. Once found, do you just check for continuity to ground?

Any and all assistance regarding the location of these sensors and the procedure for troubleshooting them is appreciated.

 

I think I've got this narrowed down to the cooling fan clutch. Now, is it possible to isolate the fan from the .5 volt reference sensor circuit by just clipping a wire(s)? I've looked into the wire loom coming from the fan clutch, but all I've been able to identify is the two wires coming from the temp sensor by the thermostat. Anyone know which wire I would need to clip or where I can find the appropriate wiring diagram?