Wiring Woes
Thread Starter
On The Tree
Joined: Mar 2003
Posts: 153
Likes: 0
From: Mechanicsville, VA
Wiring Woes Hi all. 
Been awhile since here but now I have a question someone might be able to help with. I have a question about the PNP switch, the harness I had made from Speartech has the correct orange/black wire from PCM, according to Helms it should put out 12 volts mines @10 roughly. Car will start in any gear, always had. Almost failed State Inspection, but guy is cool. Replacing carpet in car so I figured now that I'm at the wiring might as well fix. If I run a wire straight from from starter cicuit
to fix it, will it hurt PCM or affect other issues that the PCM uses that reference signal for ? I have no other issues with swap, runs and sounds fantastic.
Thx All
Been awhile since here but now I have a question someone might be able to help with. I have a question about the PNP switch, the harness I had made from Speartech has the correct orange/black wire from PCM, according to Helms it should put out 12 volts mines @10 roughly. Car will start in any gear, always had. Almost failed State Inspection, but guy is cool. Replacing carpet in car so I figured now that I'm at the wiring might as well fix. If I run a wire straight from from starter cicuitto fix it, will it hurt PCM or affect other issues that the PCM uses that reference signal for ? I have no other issues with swap, runs and sounds fantastic.
Thx All
Joined: Nov 2001
Posts: 1,707
Likes: 33
From: Anderson, Indiana
You are confusing the Park-Neutral Position switch with the Park - Neutral Safety switch. They are completely different things. The PNP is a signal to the PCM to adjust the idle speed when the car is in gear vs. being in park or neutral.
The P-N Safety switch is what prevents the car from engaging the starter when not in park or neutral. This safety switch has nothing to do with the fuel injection harness, PCM, or anything else on the engine harness. It is just a switch on your shifter that breaks the circuit to the starter solenoid based on shifter postion.
Do not try and tie any starter wiring to the orange/blk wire. That could damage the PCM. The PNP switch just grounds the orange/blk wire when in park or neutral, and leaves the wire open when in gear. This wire is not neccesary for proper operation of the engine, but is just a convenience you can hook up if you have the PNP switch available on your car.
Most of our street rod customers just cut it off or tuck it away.
By all means get the P-N SAFETY switch hooked up for SAFETY'S sake!
The P-N Safety switch is what prevents the car from engaging the starter when not in park or neutral. This safety switch has nothing to do with the fuel injection harness, PCM, or anything else on the engine harness. It is just a switch on your shifter that breaks the circuit to the starter solenoid based on shifter postion.
Do not try and tie any starter wiring to the orange/blk wire. That could damage the PCM. The PNP switch just grounds the orange/blk wire when in park or neutral, and leaves the wire open when in gear. This wire is not neccesary for proper operation of the engine, but is just a convenience you can hook up if you have the PNP switch available on your car.
Most of our street rod customers just cut it off or tuck it away.
By all means get the P-N SAFETY switch hooked up for SAFETY'S sake!
__________________
91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com
91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com
