Trooperthorn

Hey all.

I am installing the wiring on my crew project. The harnesses are out of a 91.5 ctd. I have the dealer-add-on (what some may call factory) tach and its pigtail, but the 91.5 wiring does not have the plug built-in like the 92-93 trucks do. I also have the pick-up from a 93 that attaches to the front of the engine and reads the notches on the dampner. It has three wires in its plug and is magnetic.

My question is, "How do, or even can I, put these two together to get me a working tach. I assume my 91.5 ecm has no provision for a tach signal. I was thinking I could use a unit from dakota digital or something. Any help would help.

Thanks, Eric

Buddy Stewert

I put in Tach hook up in search and found this.

https://www.dieseltruckresource.com/...ight=tack+hook

Trebor

The pre-92 tach used a two wire CPS and came with the sensor and a partial harness that plugged into the under dash wiring harness. It used a short 4 wire harness adapter that was about 3 inches in length. I posted detailed pictures last year which showed the pick up, the 2 wire harness from the CPS to the firewall, and the extension piece which plugs in under the dash in the 1990 truck that I have. The adapter section shows the color codes. Click on "my photo gallery" to view.

Trooperthorn

Was this CPS, partial harness, and short harness adapter a wrecking yard find?

Do you have any part numbers?

It looks like my best bet may be to can the crank sensor and just go with the Dakota Digital box and the alternator wire.

Any other thoughts?

Trebor

No it was in a truck that I bought a few years ago. The part numbers are long gone. I'd imagine by now even if they were still readable they would have been obsolete for many many years through Chrysler.

Crossy's son

"tdimark" has a couple kits the dealers used to install the tachs in 89-91.5 trucks, comes with everything included to hook up the tach and includes the tach as well..... he asks a pretty penny for them though because of how rare they are. and don't try to beat him up on the price because he'll just hang onto them.