Here's the issue: My truck has been experiencing an intermittent stutter or momentary power loss. Everytime it happens the engine temp is in the 200* area and it appears the fan clutch has engaged; but it doesn't happen everytime the temp gets to 200*.

I unplugged the connector at the lower left hand corner of the radiator, effectively disconnecting the fan clutch, and drove the truck about 400 miles. It didn't stutter during that time. Within 20 miles of reconnecting the fan clutch it stuttered twice.

I'm going on the theory that there may be a dead spot on the armature of the fan clutch and, that when the dead spot is alligned when additional cooling is called for, it sends a signal via the .5 volt reference circuit to the cam position sensor and ultimately there is a momentary interruption of the fuel supply.

The cost of replacing the fan clutch is unacceptable right now so I'm wondering if either of the following is possible: put a jumper between two or more of the five wires at the fan clutch connector to 1) engage the fan 100% of the time or 2) eliminate the fan clutch from the .5 volt reference circuit.

Thanks for any replies.

 

i would think that if you eliminated the fan clutch altogether, that it would run hot????i probably would do it. maybe a good used fan clutch is in order. i know they are expensive new.

 

I should have been a little clearer in my explanation. I don't want to eliminate the fan clutch altogether, just remove it from the reference circuit so it can't send a signal to the ECM or cam position sensor, whichever it does. Thanks for the reply.

 

Det 1,

I can't help you on the reference signal question, but you are on the right track here. I had a similar but worse problem myself over the weekend. Mine was continually down on power (rail pressure not reaching commanded level) when the fan clutch was plugged in. Unplug...problem gone, plug in... problem back. And I'm not talking down a little bit- more like almost couldn't drive it!! The main way we isolated this was because fan was constantly engaged, so it made sense to unplug it...

Mine isn't totally solved yet, but I drove it about 700 miles with a 5k trailer with the clutch unplugged in 80+ degrees. NEVER overheated, only issue was A/C didnt cool at idle. Get rolling and you've got a/c again.

Thia was a tough one for both of us...never seen or heard of it before- neither had Daves diesel in Muncie where Darren figured it out!!!

 

Det1 have you checked the wires that run under the oil filter and connect to the a/c pressure switch? That circuit is tied into the cam and crank sensors as well as a bunch of other things. It is know to chaff through and cause all sorts of gremlins.

 

You can ground pin #1 thru a switch in the cab and lock the fan at 85% ,it is not an instant turn on but if the clutch is good it should lock up.