tach sensor location

[DrRoscoe]

I have a stupid question, On a 1993 chev K3500 with a 6.5 turbo just were is the tach sensor located? Mine quit and look as hard as i can i can't locate it anywhere, Thanks

[DmaxMaverick]

Alternator. Not a stupid question, BTW.

[Robyn]

Just a thought here.
I just bought a 93 6.5 engine to put in my 91 and replace the 6.2

It has a sensor of some sort on the top of the oil pump drive at the rear of the engine.

What does that do??
I thought that was the tach drive as well as the input for the computer????

[DmaxMaverick]

Just a thought here.
I just bought a 93 6.5 engine to put in my 91 and replace the 6.2

It has a sensor of some sort on the top of the oil pump drive at the rear of the engine.

What does that do??
I thought that was the tach drive as well as the input for the computer????

Robyn
On yours, it is for the ECM. Yours appears (as you previously discovered) to have CA emmissions, which has an engine RPM input at the old vac pump location. If it has an OEM in-dash tach, it will be driven by the alternator.

[Robyn]

Sweet.
Well we shall see how much of this stuff can be retro fitted onto the 6.5 engine.

I need the vacuum pump to drive the HVAC system and I might as well use the original so I can hook up the computer too. The TCC IS also run with the ECM so unless I do away with the TCC which I may do. AHHHHHH what wonderful choices there are.