Forgive my first post, I have been read earthing problems on this site for a long time, just now registered. I have the engine in and starting etc. waiting on the driveshaft shop guy to fab my shaft, but my problem lies with the gauge cluster. I hooked the tach signal wire to the alt (a delco 150 amp 22si) and when the truck is running the tach does not work. If the key is in the on position, the tach works. As soon as I switch it to the "run" position the tach dies as well as the voltage meter. Any ideas? The volt gage stays dead the entire time the key is on, however when the key is cycles from run to on it will jump a bit and then rest back at the dead position.

 

Any help would be appreciated if you know any little tips. Worst case I'll go aftermarket on all my guages. Not cost effective though. I have about 1200 bucks in this truck now as it is.

 

Anyone? Could it be a wiring problem with a ground loose or bad connection? Could a bad ECM do this?

 

Checking all the grounds is the first thing you should be checking especially the one on the rear of the passenger side cylinder head.a 6.5 will do many bad things with poor grounds.

 

Not sure if you can read this but it may help.

 

Thank you, I will attempt
To follow wires on that diagram. The ground on that side of the engine head for the 6.5 should be grounded to my engine now? The dt360 I swapped in its place is grounded very well!

 

Make sure all grounds are cleaned as well even grease and grime between the starter and engine block itself can give major headaches.

 

Man that sounds great hah, I can only imagine the headache I'll run into if it's not a ground issue.

 

Not a ground issue. Could it be ECM?

 

Hmmm.. I know when I put my Cummins in my 92 that had a 6.5 it had two wires that plugged in alternator that run tach and volt gauge problem could be alternator itself wiring or stepper motor in cluster but not likely because all probably worked well before the swap?