Installing Haltech. What can I keep.
 

I started to pull things apart and noticed the stock wire harness might be connected to a few things that I would like to keep.

I would like to keep
Oil Pressure
Engine Temp
etc. All stock gauges


Also can I keep the BAC, Air bypass solenoid valve, EGR.

Thanks.

I'm sure I will have lots more questions as I get deeper into the install.

Also there was a check valve one way that was connected to the stock air inlet tube to the turbo. Is this needed.

Also it says the Control unit controls the A/C. Does this mean that I will not longer have A/C?

Also vacuum rack solenoids harness went with the main harness. I guess I will no longer need these as well with the haltech.

Did not realize that almost all of this stuff gets tossed!

Haltech forum, n00b....;)

This is not fun!!

The only two gauges that won't workt with the haltech are the coolant temp, and boost. Oil temp is on the driver's side wiring harness. If you want to keep boost and coolant you'll have to run wires from the new sensors to wherever the gauge cluster wires come out. You can keep the BAC valve you just have to wire it into the haltech wiring harness it will be an accessory item.

- Steiner

So where is the factory boost gauge ... I've been looking for mine for a long time now.

I don't know if it will work with the new map sensor. I don't have mine hooked up.

- Steiner

I was giving you a hard time because you mentioned a boost gauge indirectly here.

The coolant wire goes through the main engine harness and that is it. There is one other trick to consider or nothing on the dash will light up. It is a harness that is around the ECU harness. It is a harness that stays in the car and the wire has to be taken to GND because usually you wind up cutting the stock harness to mate with the Haltech and it gets overlooked becasue it is not on the main ECU plugs (yellow ones). I think the plug is X05, X07, or X14 and I think it relates to GNDs 5 or 6 in your factory manual.

Before you pull the engine harness, pay attention to the plug that goes to the back of the alternator. I had to take off all the factory tape and follow it all the way back through the firewall. Its a two wire connector that runs to a box on the passenger side kick panel. Something in the FSM or haynes manual says not to run the car with that thing unplugged. Thats the only thing I kept from the stock engine harness. The BAC is an accessory, as mentioned above. Its not necessary, as the car will idle without it.

I just realized something ... I'm talking 3rd gen and you guys are talking 2nd gen ... ooppps.. sorry. :(

Is this for a S4 (1988) Because nothing from the alternator cam with the harness.

Your stock harness should have a white, 2 prong plug that goes into the back of your alternator. You need to keep that wiring...since you will need to splice the FD alternator connector into it.

I'm pretty sure the stock harness does not incorporate the alternator.....

I don't think I will take this project again. Once is good enough for me.

Couple things I found out.

Rust check is insane. Its everywere!
White paint on 10th AE during washing blows out in chunks!

Are you telling me there was nothing plugged into the back of your ALT? That makes no sense...

There is. But I thought it was not on the ECU harness. Know I will have to take a look.

My original post was for a S4 alternator. The wires I'm talking about from the back of the alternator aren't part of the engine harness. They terminate at a different location, but the wires are taped to the engine harness. You have to undo the factory tape to get the wires seperate from the engine harness.