LS1 wiring logic
Thread Starter
On The Tree
Joined: Jun 2008
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From: Kansas City
LS1 wiring logic Hi everyone
I am just trying to verify I am going in the right direction so I dont blow anything up.
I am using the LS1 brake switch, PNP switch and shifter, LS1 DLC and complete underhood fuse boxes with all the relays.
So it kinda made scense to keep the LS1 C200 and C230 connectors male & female sides.
They both had the starter relay enable (YEL/BLK) and fuel pump relay enable (DK BLU) signals were comming from the BCM to the PCM which then triggers the respective relays in the underhood fusebox.
From what I have been reading, the BCM just grounds the starter trigger wire once it detects the correct resistance in the key. The details of fuel pump trigger I have not been able to find yet but I am guessing its the same logic.
So if I program out VATS out of the PCM, will these triggers still be needed ?
If they are still needed to trigger the starter and fuel pump relays can I just ground them to the body ?
Also Can I just leave the stock brake lamp, DLC and PNP connectors just unhooked and not worry about tracing each wire and removing them from the stock harness ?
Thanks
I am just trying to verify I am going in the right direction so I dont blow anything up.
I am using the LS1 brake switch, PNP switch and shifter, LS1 DLC and complete underhood fuse boxes with all the relays.
So it kinda made scense to keep the LS1 C200 and C230 connectors male & female sides.
They both had the starter relay enable (YEL/BLK) and fuel pump relay enable (DK BLU) signals were comming from the BCM to the PCM which then triggers the respective relays in the underhood fusebox.
From what I have been reading, the BCM just grounds the starter trigger wire once it detects the correct resistance in the key. The details of fuel pump trigger I have not been able to find yet but I am guessing its the same logic.
So if I program out VATS out of the PCM, will these triggers still be needed ?
If they are still needed to trigger the starter and fuel pump relays can I just ground them to the body ?
Also Can I just leave the stock brake lamp, DLC and PNP connectors just unhooked and not worry about tracing each wire and removing them from the stock harness ?
Thanks
Last edited by screaminChick-n; Jul 27, 2009 at 03:54 PM.
Thread Starter
On The Tree
Joined: Jun 2008
Posts: 109
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From: Kansas City
Anybody here or maybe one of the sponsors could answer ?
Basically how do trigger the fuel pump and starter realys once I get rid of the BCM
Here are some pictures of the wiring. Its shows an i/o switch inside the BCM. I am not sure if that symbol means ground.?
Basically how do trigger the fuel pump and starter realys once I get rid of the BCM
Here are some pictures of the wiring. Its shows an i/o switch inside the BCM. I am not sure if that symbol means ground.?
There are 2 wires in the Harness that control the Fuel Pump Relay.. when I get home I can give you the exact ones for the F-body.
The Starter is easy..run the main 12g wire that is on the IGN Switch in the Start position directly all the way to the Starter.
The Starter is easy..run the main 12g wire that is on the IGN Switch in the Start position directly all the way to the Starter.
K..PCM RED Connector Pin #9 is the Relay Signal, that one goes to the Fuel Pump Relay positive side. There also is a ground side that must be grounded, that one is in the Harness too, it's a Black/White ground.
Im kinda curious about this type of thing too. Ive got my 4.8/4L60E in the 442, and got my Speartech modified harness mostly plugged in. I used the heavy purple starter wire that belongs to the CAR and not the HARNESS. I have yet to put any power to the wiring harness, just the starter. How do I get the Neutral Safety function to work?? Obviously that when I turn the key when I get the PCM in place and all wired up, the engine is going to roll. Will it fire, or just roll over?? My harness came back from Speartech with a heavy purple wire (it might have been there before, not sure), should I use that wire instead because it comes from the PCM??
I have HP Tuners and will be tuning out VATS, EVAP, and EGR.
I dont mean to hijack, but I think screaminchick'n is sorta driving at what Im talking about.
I have HP Tuners and will be tuning out VATS, EVAP, and EGR.
I dont mean to hijack, but I think screaminchick'n is sorta driving at what Im talking about.
I don't know the specifics on the N/S Switch for the Auto..I tried wiring mine in and it never worked..someone had molested the wiring before I got to it.
I wired one in for my T56 but that's a little easier.
I wired one in for my T56 but that's a little easier.
Thread Starter
On The Tree
Joined: Jun 2008
Posts: 109
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From: Kansas City
the_merv,
I think I got the wiring ur talking about plugged in and sorted out. going thru mitchels wiring diagram book, trying to identify the wires for the C220 and C230 connectors, I cam accross the 2 trigger wires for fuel pump and starter.
I think these 2 wires are part of the VATS system and one of the many checks before an engine is allowed to start. From what I have been reading this is how it works.
Once the key with the correct resistance is put in the key lock cylinder, a signal is send to the BCM. The BCM verifys the keys and turns on the i/o switch inside it to send signals to the PCM. This is the YEL/BLK and DK BLU wires that go from the BCM thru the C220 & C230 conn to the BCM.
The PCM them sends a relay enable signal (PCM RED Connector Pin #9 for fuel) to the fuel and starter relay in the underhood fuse box.
I got rid of the BCM, I will be tuning out VATS. I have no idea about what all the tunning part of disabling VATS might involve...somehow permentley diabling the PCM PINS the YEL/BLK and DK/BLU wires go to.
I am not sure if that symbol in the posted diagram (circled red) means an I/O switch that is grounded when in ON position.
and thats my million dolor question .....at least for right now.
But thanks for confirmimg the other info on the pins.
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Thread Starter
On The Tree
Joined: Jun 2008
Posts: 109
Likes: 0
From: Kansas City
Im kinda curious about this type of thing too. Ive got my 4.8/4L60E in the 442, and got my Speartech modified harness mostly plugged in. I used the heavy purple starter wire that belongs to the CAR and not the HARNESS. I have yet to put any power to the wiring harness, just the starter. How do I get the Neutral Safety function to work?? Obviously that when I turn the key when I get the PCM in place and all wired up, the engine is going to roll. Will it fire, or just roll over?? My harness came back from Speartech with a heavy purple wire (it might have been there before, not sure), should I use that wire instead because it comes from the PCM??
I have HP Tuners and will be tuning out VATS, EVAP, and EGR.
I dont mean to hijack, but I think screaminchick'n is sorta driving at what Im talking about.
I have HP Tuners and will be tuning out VATS, EVAP, and EGR.
I dont mean to hijack, but I think screaminchick'n is sorta driving at what Im talking about.
Your are perfectly fine with asking the question....arent we all trying to get or swap started....lol
Even though I dont have 1st hand experience, I might be able to shed some light.
If u connect that large PPL wire that was in ur donor car harness directly to the starter it will work but u will loose all the saftly features that the LS1 PCM has built into it.
If u follow the PPL wire from the Speartech harness , it should end up in a relay. So u just use the ur Stock PPL wire to power ur starter relay in the Speartech fuse box.
The way the PNP and brake switch works is there is a IGN 1 voltage applied to both at all times.
for safety, the car will only crank when u have ur foot on the brake and trans is in P or N.
So when u hit the brake, there is a wire (PNK) that goes to the PCM PIN# 33 . then when u have the shifter in P or N there is another wire (ORG/BLK) that goes to the PNP switch signal PIN # 34.
This coupled with the VATS logic , the PCM will enable the starter relay.
the PNP switch usually have other wires it it, for GND, IGN 1 Voltage, Gear lock out and reverse signal.
Hope this helps a little bit
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Verdad Gallardo My 1995 had a Relay on the main wire going to the Starter that was controlled by the VATS. Basically the correct Key told the PCM to activate the Relay and complete the Starter Circuit when you turned the key to Start. From what I have seen with the car that is how mine operated.
I bypassed that and used that Relay as my N/S Relay on the Clutch Petal.
I bypassed that and used that Relay as my N/S Relay on the Clutch Petal.
After playing some more and figuring some stuff out, I think Ill be ok. The cars neutral safety switch (mounted on the steering column and attached to the linkage) will prevent the engine from rolling, and I think the PCM will take car of letting the engine fire if the PNP switch on the trans is in Park or Neutral. Haha, I think. Find out in a week, going on vacation tomorrow.
