wiring and tuning OBD II not reading tuning device

[MarauderPU]

I need some assistance tuning my motor and troubleshooting my wiring issue.

I have a 2003 Marauder chassis and motor/trans underneath a 63 Unibody pickup. The motor and trans have never been separated from the chassis. I just pulled the wrecked body off and the truck body on.

I used most of the wrecked Marauder wiring harness during this swap. I had been able to use a Diablo tuning device in the past but now something is wrong. We eliminated a mass of wiring that was not being used. I think I may have cut a wire that I shouldn't have. The issue is we only cut wires not previously connected (because we did not use many of the accessories). so cutting a wire that is not going to a ground or somewhere else should not affect the OBDII port

I am cannot communicate through my OBD II port and need to diagnose what the problem is. Without completely tearing apart the wiring harness, is there a way to determine if all the connections on the OBD port are in proper working order?

I was using a Diablo tuning device and now the car does not recognize the device (or any other scanning device), so I know its not the turner.

We methodically eliminated wires not being used, such as all the power seats windows, etc.

when connecting the tuning device, I just get a message that the ECU does not recognize the device. I get the same message when connecting a scanning device as well.

I have loaded a "canned" turn from Diablo which is working fine but I need to be able to turn for the Eaton swap I am planning

My other choice is an aftermarket ECU and sep Trans controller but that is quite involved. I want to fix this with the Ford ECU

Any advice on Wiring gurus in California or AZ would be great or comments from the techies here would be welcome

thanks

Karl

[RubberCtyRauder]

Marty and Jeff at Mos speed shop in GA. They build and tune marauders close and from afar. Even other countries by the phone and email. Sct is better for marauder than Diablo. Marty is a member here and is a contributing vendor

[Merrill]

Saw your truck on a tv show where you were road racing, really cool.
Lots of smart guys here, good luck.

[martyo]

This is not an easy one to diagnose from afar because you have cut into the harness.

Do you have a Marauder wiring manual?

[justbob]

I believe ABS, airbags, LCM, and drivers door module are all routed thru the data link. If you removed the seat harness I'd start there as the seats have air bags.


Builder Of Badassery

[massacre]

I know there is a fuse for the OBD-II connector, when that fuse is blown on our Ford vehicles, the MODIS scanner can't communicate with the vehicle.
Not sure if this is your issue but it's worth a shot.
I'm not sure which fuse it is on the Marauder, but on our Ford stuff I think it's fuse #23 or #25 or something like that.

Or I could be completely off-base here, just throwing spaghetti at the wall.

[MarauderPU]

Guys,

Thanks for the feedback. I did check the fuse for the OBD II and its OK. I do have the Marauder wiring manual on disk (for PC) and its a massive deal. You really have to be in the mood to read that thing.

I used it when I originally put the truck together.

I was trying to avoid going back to the wiring diagram and have a pro see if he could diagnose the issue.

I can dive back into the harness and start tracing wires (would rather do anything else)

[Zack]

You only need 4 wires IIRC to communicate with the OBD2 port.
Get the diagram of the OBD2 Plug.
Its surprisingly easy and all wires go straight to the pcm

[MarauderPU]

That is good to know. I was getting ready to cut open the harness and start tracing.

Now I have the courage

Karl

[Zack]

When I did my Town Car with a Marauder Harness, I used everything but pin 7.
The ISO bus is for ABS and air bags and stuff (*I think*) which does not matter in a different car.