First let me say for the electrically challenged,,, this forum is the best! Ok,,, I’m looking for a review of what I’ve done and what I’m planning,,, plus a few questions on where to get parts (drive by wire stuff).

Here’s the overview. I’m taking part of a damaged 1999 C5 (drive by wire) harness and a 2000 F body harness and making a good one. I also picked up a PCM (2001?) at my local Corvette salvage house and I’m trying to mate everything up. I’m running a Vintage Air Mini system as well as a single Spal 16” fan. Also,, I wont be using the C5 tanks and pumps,, going with fuel cells and external pumps.

First, I’ve removed the following from the F Body PCM connectors:

TP pins - Blue 8, 60 - Red 24

Transmission pins - Blue 17, 18, 53, 79 - Red 6, 8, 44, 47, 48, 51, 63

Fuel Tank pins - Blue 23, 46 - Red 54, 64

EGR pins - Blue 41, 47, 55 - Red 7, 41

AIR pins - Red 4, 36

EVAP pins - Red 34, 45

AC pins - Blue 45 - Red 14, 17, 18, 43

Rear O2 Sensors - Blue 25, 28, 65, 68

Cruise Control pins - Red 13, 37

IAC pins - Red 76, 77, 78, 79

Spark Retard - Red 53

PNP - Blue 34

TCC - Red 2, 42

Tach - Red 10 (doing this a different way)

VDT - Red 30

Engine Cooling Relay 2 & 3 - Red 33


Does this look correct????? Did I pull something I might need??????



So what I believe I’m left with is a very basic harness. I need to supply power to the system via:

Blue 20, 10 Amp, orange wire, constant power
Blue 57, 10 Amp, orange wire, constant power
Blue 19, 10 Amp, Pink wire, switched power

Also switched power is needed for :

Injectors & coil packs driver side – pink wire 15 Amp
Injectors & coil packs passenger side – pink wire 15 Amp
O2 sensors & MAF – Pink wire 15 Amp
TAC Module Pin 7 – Pink wire 15 Amp

Does this look Correct???

Grounds:

1 - Blue 1, 40 - Red 1,40 - Low Oil Switch, MAF
2 - O2 Sensors
3 - Coil Packs

Does this sound correct??


SPAL Fans –
The fan came with its own relay, so the thought is to connect it to Blue 42, Engine Cooling Fan Relay 1 as the fan is only a single speed. Also,, Vintage Air makes a pressure switch (Trinary) that is a safety switch as well as a fan trigger when the AC is turned on. This should keep me from having to deal with the PCM knowing the AC is on.

Does this sound correct????


Last but not least, I need to incorporate Drive By wire into the harness. I’m looking for the TAC Module C2 connector (with pigtails I hope) and a TAC module. Anyone have one they might like to sell?????

Any comments and or suggestions are greatly appreciated!

Thanks!

 

Why are you eliminating wires for the trans? Are you going to use a stick trans?

You should probably have the PNP switch wire since the PCM uses it to control idle speed. I don`t see any problems with the rest of the wiring, but I have never wired anything with drive by wire throttle either so?

 

is that the factory5 kitcar? how far along are you?

 

if he is putting it in the GTM it will use a g50 or g50 variant trans so therefore he wouldnt really need all the trans stuff i suppose. As far as the PNP switch I didnt use it on mine...all i saw it for was it limits RPM in P or N so you cant over rev the motor above i think like 3k rpm. Correct me if I am wrong but i dont see any need for the PNP if you dont need it.

 

I did a bit of research on the PNP pin this morning. As I’m planning to set up the cruise control,, it shouldn’t be an issue as I’ll have to put a switch on the clutch and brake pedal to disengage the cruise control. I’ll still research it a bit more,,,, although it looks like both need a 12v signal that goes to 0 when the pedals are pressed.

As far as the trans,, yes it is a G50 Porsche box. I’ve got the suspension and steering in and all of the aluminum panels have been drilled and powder coated, AC/heat system is in as well as the cooling systems modifications. . The motor is about ready to drop in so that’s why it’s time for the wiring.

Let me ask an additional question if I might. The kit uses a Painless Chassis Harness with a 30 Amp switched circuit to run the motor. Normally the kit calls of it being spliced into the C5 fuse box although I don’t have that. Is a 30 amp circuit enough to run all of the motors switched circuits? When I add up the amps on the LS1 switched circuits I come up with about 60 amps. Am I looking for trouble if I don’t use relays here?

Thanks again

 

Fred,
Was the C5 harness badly damaged? Why didn't you use the C5 harness instead of the Fbody? If you plan to use the drive by wire then stick with the C5 harness and use the underhood fusebox. This way you don't have to play around with the TAC wirings and everything else. All you have to do is hook up Batt, IGN and the starter wire to the fuse box and it will start up. Also if you plan to have AC in the car then why did you remove all the AC wires from the PCM? If you plan to use the DBW then you will have to use a C5 firmware. The way you have the harness right now you have to use the Fbody firmware. GL
Nice project
Vinh

 

Well,,, the C5 harness had the two 80 pin and the fuse box connector cut off by the auto recycler,,,, and there was no fuse box or PCM,,, that’s why I using the f body harness. I thought about getting another C5 harness but I got a good deal on the F body harness and I knew I’d be ripping it apart anyway. I already have the pedal and pedal to TAC wiring, the wiring at the TB,,,,, I just need to TAC C2 connector and the TAC module

I may still end up getting a C5 fuse box,,, but I don’t have the connector from the motor as the F body doesn’t do it that way. I’m trying to find a reasonably priced alternate solution.

As far as the AC wires,,,, since it’s an aftermarket AC and I can trigger the fans externally (I think!!!) I didn’t see the need to hook it into the PCM,,, but maybe I’m missing something here. Am I???

I did get a PCM from a C5 so it will had DBW

Thanks!!!

 

Fred,
I see. If you don't have the fuse box it's OK. No a problem. The problem is if you use the fbody harness and you want the DBW then you will need to add more wires to the PCM for the TAC. Then reprogram your PCM to a C5 firmware. Make sure you have a 99 and up PCM. This is where you need John at Speartech to help you out with the wiring. If you need any help let me know.

For the AC the PCM controls the AC system and it needs to monitor the AC status. For example when you turn the AC on the PCM needs to raise the RPM and turn on the fan etc. The C5 firmware is very sophisticated. It controls every little thing that you can imagine. I guess because it wants to save the engine incase of something goes wrong. GL
Vinh

 

Real good point about the RPM when the AC is turned on,,, it didn't even cross my mind. Would you happen to know,,,, is it just AC status that I need to worry about here???? I'll give Speartech a call,,,, maybe they can hook me up with what I need.

Thanks!!!!!

 

There is one more thing with the AC system is there is a pressure switch on the high pressure side line. If for some reasons it detects too much pressure in the line it can shut down the AC automatically. Now if you have manual control it would blow up right? lol.

You are a brave man for someone who is a rookie with wirings. One thing I forgot to mention to you is the pin out of the PCM connectors are different between the Fbody and the C5. So you will need to make up your mind which system you want to go with either fbody or C5. Otherwise when you switch from an fbody to C5 firmware you will need to repin the PCM connectors. I did this for my swap and it wasn't fun. GL
Vinh

 

Depending on what style compressor he is using it may have a overpressure release valve on it, that was how the older style GM`s got away without running a high pressure cutoff switch.

You don`t absolutely have to let the computer know the A/C is running, if you don`t it will not step the idle RPM up, but the computer will compensate for the added drag and open the throttle enough to make the motor idle at its baseline RPM.

 

First the good news,,,, I called John at Speartech today,,,, he hooked me up with the needed connector for the TAC module (with pigtails) as well as the TAC module. Nice guy and a real pleasure to talk to. I wish every supplier was!

The AC system I’ve put in is a Vintage Air Mini system. They have a switch they call a ‘Trinary Switch’ that appears to handle high and low pressure so nothing gets damaged as well as controlling the fan when the AC is turned on. If you are curious take a look at:

http://www.vintageair.com/downloads.asp

See the ‘Trinary Switch’ pdf,,, seems straight forward but maybe my inexperience is leading me.

I’ve also come to the conclusion that I’ll add a fuse block with a number of relays to handle the power to the motor,,, better safe than sorry.

Thanks again!!

 

How was the build on that GTM? I built a cobra back in 2000 and love it. I got a notice for the GTM a few months back but I already have to many projects to get one right now. Besides a good G50/50 to hold any kind of real power cost like $14K

Mike