aftermarket tach to the obd1 port?

[gp90se]

Ive got a 4" tach laying around, and I was thinkin, if you can get the RPMs from the obd1 port (orange wire) can the rest of it be wired up into the port or do I need 2 get power from elsewhere?

[Justin]

The orange wire won't get you anywhere, but I think you can go to the white wire in pin C of the 6 pin connector at your ign. module. That's where the GPs get their tach signal from for the cluster. I'm guessing it puts out a 6 cyl signal.

[gp90se]

I think the orange wire will work....

 

http://www.w-body.com/forum/viewtopic.php?t=4551&highlight=rpm+orange+wire&sid=211dbf696c1397a711c170b208fcc9c4

 

Look at Lee's post

[Hairdo12]

If your tac can read the GM chatter from the ALDL then connect it to the orange wire. If it is a pulse counter like almost every after market tac I've seen then its either the white wire mentioned (I personally never used it) or the small purple wire by the ICM. I use the small purple wire for my remote starters tac signal and an aftermarket tac b4 the ub3 came along... by the way I believe in the topic mentioned above they are talking about using the orange wire for a digital dash cluster and that is why they need the orange ALDL feed.

[3pt1lumina]

I don't know about aftermarket stuff but when I wired my ub3 tach, I had to use the white wire with NO black stripe on it. I ran a wire from inside the engine compartment by the ECM over inside the car. Works great but I don't know if this helps in this scenario.

[jeremy]

please don't put a 4" tach in a w-body....

[gp90se]

I have it laying around, there's no tach in my buick, might as well put it in.

 

EDIT: ive been edited

[dbtk2]

4" tach in a w-body = you need to be shot

[Justin]

I don't see what's wrong with putting a tach in a car that probably doesn't have it from factory. If I had the tach laying around and didn't have one in my CS I'd sure use it. This site is becoming annoyingly narrow minded when it comes to modifications done to cars.

[gp90se]

Justin, this is what happens when ya have know it alls who have it thier way or no way. It's your car, do as you please to it.

 

But anyways, anywhere in the cab I can pickup the tach signal without running a wire 2 the bay?

[Crazy K]

What car are you working on? The tack wire will not be inside the car, unless it had a factory tach. Refer to FAQ lumina cluster info for how to find the wire, it's very simple, but will have to be run.

Besides, it would look so tachy... pun You should upgrade to a deluxe cluster instead.

[Justin]

What car are you putting it in?

[gp90se]

the 89 buick

[Justin]

Yeah even if you had the UB3 cluster in that car you'd have to run a wire from under the hood. The wire you need should be a white wire in the 6 pin connector on your ignition module, the 3rd pin in, letter C. I'm sure it goes directly from the ignition module to the ECM, so you're going to have to run a wire inside. It's not that terribly difficult but Ws aren't the most fun to get through the firewall.

[Crazy K]

thats true that it's at the connector, but A simplier much less obvious wire location was found by me when I dissected several wiring harnesses and parts as listed below.

 

Read for info.

http://www.w-body.com/forum/viewtopic.php?t=36972

 

The wire is only in the the engine side of the fire wall and doesn't continue into the car. white wire is the only one on this harness and so simple to do!

[WhiteMonteZZZ]

I know when I had my dash apart in my Monte and was testing a shift light I was going to put in my T/A, I used the white wire going into the gauge cluster on my Monte and it triggered the light just fine. Shift light uses the same signal as a tach. And the 95-99 tachless Luminas all already have a tach signal wire going into the gauge cluster.

Just curious as to roughly when this change occured.

[Justin]

The grand prix uses the white wire for the tach as well, but the regals and Cutlass's use the orange data wire. I was surprised when I was upgrading my friends' '89 GP as well that we had to run a wire from out in the engine bay.