I'm alomost done with the big block conversion on my '87 GTA, but I still need to connect the oil pressure gauge to the sender and the tach to my MSD box. Is there a place I can find these leads under the dash without tearing the cluster apart?

I would have thought that these would terminate in the engine bay, (like the water temp which works fine now) but I can't seem to find them. The only wires I have are the ones that ocme through on the driver's side. Everything having to do with the computer and the pass. side harness has been removed.

Any help would be appreciated!!!

Thanks,

Don

 

Your oil pressure wire should come from the drivers side bulkhead connector (tan wire, black stripe) and the tach lead as well (white wire).

If you get under the dash & pop the cover off the backside of the bulkhead, you should find the same color wires there as well.

 

Those are the wires that my manual tells me to look for, but they aren't there!

I guess I'll have to get under the dash to find them.

Where's the best place under the dash to pick them up at? the firewall connector or is there another apot they run through?

Thanks,

Don

 

On my car the tach was on the passenger side next to the fender. There was a clip on the wire that you can just unplug, start then engine and the tach dint move. If you plug it back up and crank her the tach moved so we know that was it. That damn wireing chart said it was behind the block on the driver side.
What ever that just wasted alot of time and battaries to power the flash light.

 

Yup, that's what I discovered too. (Un)fortunately, the entire passenger side of the care has been "de-harnessed" since carburators don't really need an ecu to run them. I'll look in that area for the tach lead.

Any clues on the Oil Pressure wire ? ? ?

 

I'd say at the bulkhead. (On mine) The wires are all wrapped up in tape and that was the easiest place (for me) to get to them when I moved the module for my headlights inside the car.

The wires can be anywhere under the hood but, ultimatly end up at the firewall (bulkhead) connector next to the brake booster. Neither the oil pressure nor the tach lead have anything to do with the ECM harness from the passenger side.

If you were to unplug the harness at the firewall, the wires on the inside of the car should be located on these 2 terminals. You should find them in the same place if looking at the backside of the plug.(I think that makes sense)

 

Ok, good deal.

Thanks a lot for the help!

Don

 

Ok, new problem . . .

I located the pins and the wires just fine (THANKS deadbird!) but I'm getting no response from my oil pressure gauge. It stays pegged at its max as soon as I turn the key on. THis is the same thing it was doing before I hooked up the wire. Just for comparisson, I attached an autometer oil pressure gauge that I had off another car and it showed no response at all.

Do I have the wrong sender? It's the Borg Warner replacement sender and the PN on the cover of the box is S996. It appeared to have only the provision for one wire to hook to it which is all I have connected, straight to the tan wire at the bulkhead connector.

Thanks,

Don

 

Ok, according to carparts.com, I have the right sender.

Only one wire connected to it and that goes straight to the tan wire in the socket pointed out by 'deadbird'.

Whether the wire is connected or disconnected, the oil press. gauge goes straight to max and pegs there as soon as the key is turned on.

Ideas?