I bought this truck used and noticed that It has a chrome fuel rail ..I am thinking that that is not stock?
2nd question When I start the truck (cold) I noticed that the voltage will jump up to 14 volts than down to (guessing here) 10 volts and back up again. It will do this 3 or 4 times. I am thinking that it is the glow plugs going on and off but with the truck running I would think that the batteries and alternator would be able to keep up with that...At least not drop the voltage so fast ..Every thing in the truck dims when that happens even if the only thing on is the dome light.
I did notice that the wire going to a relay (kinda looks like a starter relay) was burnt pretty bad at the connection to the relay..I cut the connector off and re soldered a new one on it..cleaned all the battery connections etc.
Any Ideas what else may cause this?
Thanks

 

your truck has a grid heater not glow plugs. your volt gauge is right. the grid heater draws a bunch.

 

Is it normal for the grid heater to come back on once the truck is running?

 

My truck does the exact same thing but when it warms up or start driving it it stops.

 

seems a waste since it is running...

 

yes they cycle several mins when cold. all the models does that even my 91