Hi, when I hook up my alternator wire to my msd negative terminal the alternator goes all the way to 8000 rpm and stays there until I turn off the ignition, when I turn the ignition back on it resets to 0. Originally this car had the electronic fuel injection and I am wondering if I am hooking my white alt wire to the correct point on the distributor or should I hook it up to another source such as the alternator? any help would be appreciated.
This car has also been converted to right hand drive so wiring loom is a nightmare....

 

 

thanks very much, enjoying the build on this, planning to change the dash as when they did the right hand conversion they replaced the facia with an mdf model, plan is for an alluminium fascia on it as its looking pretty baggy, can start some pics of the project if anyone interested, want to keep with the original gauges if I can so appreciate any feedback. Planning to revin it to be comp car and every day driver with half cage, and have it on the road in about a month once I have sourced some seats, cage to come later, drivers seat adjuster is kaput and fabric has failed around some high points inside the seat and dont want non matching front seats, are there any other nz vehicle seats (japo unfortunately not a lot of pontiac stock in this area) anyone is aware of that have the same floor bolt plan?.

 

Howdy.
I've got a similar problem. I've probed the connections behind the actual gauge. The ground, the 12+ seem good. The coil connection is what is confusing me. When I connect a test light across the ground and the coil signal, what should I be getting?
When the ignition is on the test light lights. With the engine running it still lights, but seems brighter.

I've even probed at the actual dizzy itself and get the same outcome.
It's driving me nuts!!

 

With the engine running, the white B- wire should show a pulse. However, even at idle, the frequency is high enough that it will look almost steady on a test light. To actually see the pulse, you need a lab scope. This b- circuit is what you need to drive the tach.

 

So even with the ignition on, but not running, should there be voltage?
The problem I am actually having is that as soon as I start the engine, the rev counter just spins all the way around and sits there. Could the gauge be at fault?

 

Yes and yes. There will be voltage on the white wire with key on. It is ignition voltage through the coil primary. The factory tach driver module is a common failure item. You can have it repaired by a speedometer shop or do a search here on TGO for threads on repairing it yourself.

 

Cheers all. Is the module physically attached to the gauge? If so, it might be easier for me to replace the gauge. Here in Australia, it isn't easy to find places to work on T/A's (at least not in South Australia anyway).

Thanks