When I am at idle, my tachometer sometimes drops to zero and the overdrive light starts blinking. As soon as I rev up the engine, the tach works again and the blinking light goes out.

Could it be my tachometer sending unit is malfunctioning? If so, where is the best place to get one? Or what else do you think it could be.

As usual, thanks a bunch for the help. YOU have kept my baby running for 9 years

Tom

 

The tach sender is a Ford or IH part only. It sounds like it is on the way out. Check the 2 wires that come out of the sender, if they are bare, a new one is in order. Some have reported that removing the sender, and cleaning it helped, but it was a short time cure.

 

What he said ^^^ Typical tach sensor failure. It is the big nut with the wires coming out of it on your IP gear housing to the right of the oil fill tube on the 7.3. Look for bare wires at the top of the nut. It's a dealer only item around 70 bucks.

 

cleaingit wll fix it, i its very short lived. mines been on its way out for about 6 months, it dose the same thing ours dose, but since i have a manual trans it really dosnt matter for me, ill fix it one of these days. if you have an e4od youll want to get it fixed ASAP

 

Thank you all for the come-back. I will get on it right away
Tom