Cascade Crew

[scott in wa.]

1988 tbi 305 car, to a 91 S/D harness with HSR 350.

I have been poring over two GM manuals this weekend (these books are massive)
The 88 and the 91 manuals, looking for differences in the 88 tbi and the swapped in 91 s/d harness
There are differences in the Bulk head connector which is at the driver’s side fire wall; there are two plugs at this location that make up this connection.
There also appear to be some differences in how some of the sensors are hooked up (I will have to get back to these with examples at a later time).
There may be some difference in the I/P connector right near the ECM This connector does more than just the instrument panel, GM calls this a 15 way I/P connector (HA).

Anyway, yes Iam having fits about this wiring harness that we swapped into our car. It started out by trying to find our windshield wiper wires but lead to many differences in the inside wiring of the car (bulk head connector and the 15 way I/P connector) these will affect how the car will run and how you see set alarms and engine lights.

Questions: Holley Commander or a stand alone wire harnesses,
If you install one of these harnesses into your car, how do you get around that bulkhead connectors and that 15 way I/P Connector?
Also the windshield wipers and gages.

We are thinking about going that route, the commander or some other stand alone harness that will plug into our new 7730 computer.

Help

Scott

[Twilightoptics]

If you purchase the c950 setup with TPI harness this is how it works:


You unplug all your sensors, and plug the c950 in. You need to wire in a wire for the fuel pump relay, a wire for ignition power, 2 leads go to the battery (pos and neg), you wire in one wire for A/C, one wire for Fans.

Wiring diagram is easy.

The rest just plugs in. It comes with a new map sensor and Air Intake Temp sensor. Uses the rest.

What I did to all the connectors: say the TPS connector.... I followed the wires back to where they either go to the bulkhead, or if they mated with a bunch of different wires (IE mass soldered ground or power) and cut them off flush there.

Did that to all the wires I didn't need. Unplugged the ECM and just stuffed the factory ecm connector up into the dash area.



The c950 runs FUEL and SPARK ONLY! With signal leads for the fans and the A/C.

If you don't have wiring in properly for the wipers/etc it sounds like you may have swapped in more harness than you need. You should have left the TBI harness, overlayed the 91SD harness and just hooked up engine management controls.

Again the C950 just does fuel and spark.

[Twilightoptics]

Full C950 manual here:

http://www.holley.com/data/Products/Technical/199R10149-7.pdf

page 110 is the wiring hookup for the C950.

Also a lead for park/neutral.

I don't have AC so I unpinned the AC lead B8 and used it for Cooling fan C1. You also don't need the coil - wire C11 so you could use that for the fans also if you have AC.

My box did, but wasn't "supposed to" come with the late model distributor adapter. Theoretically the c950 comes with the big plug for the large cap HEI distributor on the '85 and '86 and the Vettes. So you need this connector that plugs into the harness, then into the dizzy. It also has a single wire disconnect for timing. I can't find the part number so all the new C950 may come that way.

Also comes with a new heated O2 sensor.

[scott in wa.]

what did you do with that bulk head connector and the 15/ way i.p connector??
what about your gages, and engine light?, ADL? wipers???

How long did it take you to get this in? and running?

What year is your car??

thanks

[Twilightoptics]