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Us the c100 its easy. Only handful of wires you keep to run to your holley hp harness and starter
c207 you can go without except for the alternator wire if you have a 2 or 3 wire like my 89 did. The small wire is the charge indicator and to excite the alternator
I did use the factory starter wires and and other accessories from the c207 harness. I used a split grommet from summit. They sell different size ones. I had to run a couple wires for my gauges in through there along with the usb and wires for the digital lcd screen.
I couldn't find a grommet like that before. Cool, I'll have to check out Summit again for it.
Us the c100 its easy. Only handful of wires you keep to run to your holley hp harness and starter
c207 you can go without except for the alternator wire if you have a 2 or 3 wire like my 89 did. The small wire is the charge indicator and to excite the alternator
Thanks Orr, I was under the impression that was where the exciter wire was for the alt. I'll have to check some threads for which wire it is and get that taken care of, the rest seeeems to be pretty straight forward now.
Us the c100 its easy. Only handful of wires you keep to run to your holley hp harness and starter
c207 you can go without except for the alternator wire if you have a 2 or 3 wire like my 89 did. The small wire is the charge indicator and to excite the alternator
Little late to the party, but the C207 info isn't correct
Several years and engines require a wire or three from the C207/C221. You'll have to look up what goes where. I posted a comprehensive C100/C207/C221 pinout list in the additional info thread on the LSx forum. Sometimes it's just a ground wire for the gauge cluster, others like the MIL lamp, P/neutral circuit, TCC brake input and several 12v switched inputs (originally INJ/ECM power). Earlier cars with the CCC were more accepting to dropping all of the pass side wiring and several even disconnected cleanly. Later EFI cars simply do not
For clarity, here are the most common C207's
85-87 carb
B LT GRN back up lights (Manual)
C BRN/WHT MIL
F PNK/BLK 12v IGN to ECM
G DK BLU back up lights (Manual)
M BLK/WHT gauges grd
N ORN/BLK P/neutral (auto)
P PPL TCC brake input (auto)
85-87 EFI
C BRN/WHT MIL
D TAN/WHT 12v to fuel pump
F PNK/BLK 12v IGN to ECM
G PNK/BLK 12v IGN to emissions
K BRN speedo
M BLK/WHT gauges grd
N ORN/BLK P/neutral (auto)
P PPL TCC brake input (auto)
C221
A PNK inj bank 1
B DK BLU back up lights (manual)
C TANk/WHT fan relay 12v IGN
D PNK inj bank 2
F LT GRN back up lights (manual)
88-89 EFI
B PNK/BLK inj bank 1
C BRN/WHT MIL
D TAN/WHT fan relay 12v
F PNK/BLK 12v IGN to ECM
G PNK/BLK inj bank 2
K BRN speedo
M BLK/WHT gauges grd
N ORN/BLK P/neutral (auto)
90-92 EFI
B PNK/BLK inj bank 1
C BRN/WHT MIL
D GRY speedo (v6 and TPI)
F PNK/BLK 12v IGN to ECM
G PNK/BLK inj bank 2
K BRN speedo (TBI only)
N ORN/BLK P/neutral (auto)
"You can use the i/o harness to control your fans if you want to set it up that way."
Yes, I want close to factory control as I can on everything, so i will go that route, but I'm still wondering if I need anything from the c200, not sure what all it was for. Does the fuel pump need it or?? I'm planning on using all my factory gauges. I put in a brand new a/c conversion system made for this car, so the wiring is the same (except for the compressor is on opposite side). I'm thinking with the holley harness, that I will have everything I need to plug in for the ecu side of the harness (sensors, injectors, etc) and was thinking with the exception of what I mentioned previously, that the c100 harness that I left on would have everything I else that I needed to hook up the acc's/starter/etc.
Also, did you mount the ecu under the dash like the factory was? If so, what did you use to "plug up" the entry hole in the kick panel for the harness? I read someone using spray foam (and not working to seal it up), and another using original rubber grommet, but painfully taking it apart from the octopus mess of wires and glue. Neither way sounds good to me, and I definitely don't want to leave it open.
I re-used the factory pass-thru. It was a pain to get it apart without breaking it.
Good find Tuned Performance, but man that's steep. Exactly what i'm looking for, but a 100 bones. My only option I can think of doing with it (to make it clean and sealed good enough), would be to seal and rivet on a cover that has a hole made into it that fits a standard grommet size over that factory hole. I just don't want to trash the factory harness laying over the sad abandoned 305 in the corner...
That's actually very cool and isnt really bad in price compared to what were doing to ours holley hp efi system and a custom wiring harness by efi connection I'm hoping he used that for our build..
12-11-2019, 08:05 AM
