89fast5oh

I am swapping a 1991 TPI harness into my 85 that was originally TPI but had the wiring harness removed.

Looking at the C100 connector pinout most all the wires line right up except for a few of the "C" and "D" pinout wires.

What will need to be changed to make the harness's compatible?

I've looked at the AustinThirdGen wiring diagrams, but without knowing where the other wires come from that go into the harness, it doesn't make much sense.

John in RI

iTrader: (167)

There were a lot of changes from the 85 to the 91 C100 connector. Even the headlight side of the connector changed alot. ( For example,... the wiper wiring was moved from the engine side of C100 in 85 to the headlight harness side of C100 in 91. )

Here is the 85 C100:


Here is the 91 C100:




Having both the C100 diagrams should tell you where all the wires are located and what they are all used for. I'm sure that you are aware that the 91 TPI system was a Speed density system and teh 85 was a 1-year MAF system,..... it will take some effort to get everything working properly - regardless of what type of TPI you are planning to use.

Good luck !

89fast5oh

I should point out that my car has a working C100 front light connector, but the engine harness connector is gone. Car was converted to carb, the C100 bulkhead connector was cutout and wires soldered straight through. All lights front and back work, the starter and alternator systems works fine.

Do the C100 connector pinout initials correspond to any other wiring schematic? Going by the Austinthirdgen.org page, there is only 1990 or 1992 so I am going by the 1992.

The pinouts I am most confused by are the:

1992 C100 harness C7 - BLK/WHT "Engine". - What is that wire? Where does it go? What schematic do I look at to find out?
1992 C100 harness G4 - GRY "Engine: Fuel Control" - Is this the fuel pump relay wire?
1992 C100 harness G8 - BRN "Starting and charging system: charging coolant fans (coolant fan relay)" - From the fuse panel to the alternator?

1985 C100 harness F8 - BRN/WHT "Charging System" - Is this the wire that runs to the alternator from the ignition switch?


I am not too worried about the 1985 wiring as I don't assume I need to even worry about it at this point.

If I can locate and decipher all the different wiring diagrams, I should be able to figure this all out in time.

The main question I have is that other than the power distribution, starter, and charging systems in the C100 bulkhead, (i know about guages and wipers) what really makes the whole system run? If there is power to the PCM and the previously mentioned systems is that all it takes?

To really take the complications out of the equation we could say that I am just swapping TPI into a older GM vehicle.

John in RI

iTrader: (167)

Yes,.... the 85 used a 2 wire connector for the Alt. and I believe that pin F8 is that circuit.

You will have to add what-ever is needed by the 91 system to the 85 wiring, whatever it might be. Fuel pump, Fans, VSS info for the PCM, Vats signal to the ECM,... whatever is missing from the 85 wiring and need by the 91 set-up will need to be added.

You will also need to focus on the C207 Dash-to-ECM connector as well as C100. I'm pretty sure there will need to be changes / modifications at that plug as well.

Here is the 85 C207 pin/circuit locations
1985 C207

Black Plug

PIN Color From / To (Notes)
A Brn ALDL / ECM (AIR control)
B* Dk Blue BU Fuse / Back Up Switch ( V8 T5 )
B* Red ALDL / Fuel Relay ( V6 - TPI )
B* Org/Blk FP FUSE / Fuel Relay ( L4 )
C* Brn/Wht ECM / CE Light ( L4- V6 - TPI )
C* Wht/Grn Light Driver / ECM ( LG4 & L69 )
D* Blk/Org FP/INJ fuse / Fuel Relay ( L69 )
D* Tan/Wht Puel Relay / Fuel Pump ( V6 )
D* Lt Blue Puel Relay / Fuel Pump ( TPI )
D* Tan Oil P Sensor / Oil P Gauge ( L4 )
E Wht/Blk ALDL / ECM (test)
F Pnk/Blk IGN fuse / EGR-ECM
G* Dk Blue BU Fuse / Back Up Switch ( V8 T5 )
G* Pnk/Blk Gage Fuse / MAF Relay ( V6)
G* Pnk/Blk Gage Fuse / Burn Off Relay ( TPI )
G* Pnk/Blk Gage Fuse / Air Cond Relay ( L4 )


White Plug

PIN Color From / To
H Tan/Blk ALDL / TCC-ECM
J* Ppl Starter / Fuel Relay ( L69 )
J* Org ALDL / ECM ( L4 - TPI )
K Brn ECM / VSS
L Tan/Wht Fuel Relay / Fuel Pump ( L4 - L69 )
M Blk/Wht VSS,P/N switch / Grd
N Org/Blk ECM / P/N switch
P Ppl Brake / TCC
R Ppl/Wht Crank Fuse / Cold Start-ECM ( V6-L4 )


On several of the diagrams the wire color changed from one side of the plug to the other ( dash harness vs. ECM harness.) In this case I used the DASH harness color. I did not take the time to pull out each of the dash harnesses from Stock to review tham - so It's possble that I missed a wire or 2. If anyone spots a problem just let me know and I'll edit.

Here is the C207 connector for the 90-92 ccars




You'll have read thru all the wiring schematics for each system to locate the circuit in question to find out exactly what's what. Best $$ you'll ever spend on this project:

1991 Chevrolet Camaro service shop dealer repair manual
http://www.ebay.com/itm/1991-Chevrolet-Camaro-service-shop-dealer-repair-manual-/310711248459?pt=Motors_Manuals_Literature&hash=item4857d5664b&vxp=mtr#ht_1355wt_660

Slowride02

there is a 6 pin plug as well do you have the sheet on that?

John in RI

iTrader: (167)

For 1985,....

Plug C221

A Pnk/Blk Inj2 Fuse / Even Fuel Injectors
B Lt Green Back Up Switch / BU Lights ( V6-T5 )
C Brn Fuel Pump-Fan Fuse / Fan Relay ( V6 - TPI )
D Pnk/Blk Inj1 Fuse / Odd Fuel Injectors
E
F Dk Blue Back Up Fuse / Back Up Switch ( V6-T5 )

85RS

The wire for the tach pin is black/white, anyone know what that's about? I traced it a good ways through the harness and it hits a conectorcand then disappears back into the harness, havent finished tracing it yet...85 sc, originally a mpfi 2.8l

John in RI

iTrader: (167)

The TACH wire for the 85 V6 is WHITE on the dash side of C100,........ and WHITE/BLACK on the engine side. It passes thru the firewall on PIN 'D6' on the C100 connector. Here's the schematic for your 85 MPFI:

85RS

Thanks for the reassurance bud, cleared it up for me!

85projectZ28

I know this is an old post, but I’m working on mine now and this helped. JohninRI, post #2 was exactly what I needed! Thanks!