Removal of unused wiring loom

[DJ]

As part of my Megasquirt EFI upgrade, I've decided to take the plunge and remove all of the old unused wiring in the engine bay. I've been meaning to do this for some time but I figure now is as good a time as any.

For the moment I only plan to cut it back to the bottom left side of the engine bay where it comes through from the passenger compartment. At some later point I'll finish removing the rest of it.

I'll be removing the "fuel pump start" and "fuel pump run" relays and all of that attendant wiring. That'll leave very little wiring from the original loom.

My question is about the "AC idle step-up" relay and wiring. I DO plan to install a new AC system a bit further down the road (already have most of the new system). I can't see where I'll need this relay and wiring for the new system so I want to also remove it from the car.

Am I missing anything here or should I leave this wiring in place until I do the AC system? I guess I could just coil it up down on the bottom left side for the time being until I figure out the AC.

[DJ]

Answered my own question.

After removing all the wrapping I found there was only one wire from the AC idle step up relay that went all the way into the passenger compartment. All other just went elsewhere within the engine bay.

I cut it and tagged it for easy location later if I should need it.

[Will]

You have an MS-II, right? Have you done the mod for using IAC? This solves the problem that the AC relay was supposed to in the carbed car. If you want pictures of how to do the IAC mod on the MS-II, I can take a pic of the jumpers for you, they are already done on my unit. Then you get yourself a small bipolar stepper IAC. I have one from a Nissan because it's a block that can be external, many are mounted directly to the TB.

The MS-II incorporates an H-bridge that will drive the small stepper directly, no need for an external stepper driver. And then you have (hopefully) perfect idle control, with just a tiny momentary dip when the AC cuts in.

[DJ]

Thanks, Will. That's pretty much what I had figured.

I have the MS II, PCB 3.57 which already has the IAC circuitry in place. The only things I've needed to add for my intended usage are the ignition driver and the dual MAP sensor.

I'm using a Jeep stepper IAC with the machined block that DIY Autotune sells for mounting it. Now just need to find a good place to mount it. Idle control has always been the bane of my Lancia existence here in the Rocky Mountains so I have high hopes for the new IAC.