Loose-Goose1255

I'm new to tuning and stuff, and I have a haltech 550 to go with my new TII motor. I'm pretty comfortable with the wiring of sensors and engine management but now I'm hitting an area of unfamiliarity. How would I keep things like my power windows and gauges? Is there a seperate module that controls those or do all of those features connect to the haltech? Thanks for any help, I'm just trying to keep my gauges windows and a freaking radio😭😭

j9fd3s

iTrader: (3)

if you look at the wiring diagram the ECU really only runs the engine, so none of the stuff you mention is affected (effected?)

rotary_fan

I’m in the same boat as you, but haven’t started with the actual work. The following statement is just hearsay:::: I believe I’ve heard you’ll loose the stock boost gauge, wiper and ac controls.. but that is all. I’ve read posts where you can rewire the wipers to make them work as stock and use the haltech to control the ac condenser etc.

Just wanted to throw that out there in case someone with more experience can validate and provide more solid info.

Brrraaap

Well I know on an NA '90 with the engine and ECU removed everything works, can't speak for the AC controls or the wipers, make sure to ground the harness at the ground near the ECU or it does weird stuff.

WondrousBread

The ECU on our cars is stone-aged. It only controls engine functions. It doesn't drive the gauges, monitor temperatures, or anything else. All of the gauges (other than boost possibly) are driven by simple sensors. The tachometer is driven directly from the coils. The windows, wipers, and everything else are just simple logic with switches and relays. In fact, the stock power windows don't even include relays, which is why the switches fail so often.

The ECU doesn't interact with anything other than the AC switch.

You can pull out the ECU tomorrow and everything will still work. Boost gauge might be an exception since you aren't keeping the MAP sensor or the engine harness.

j9fd3s

iTrader: (3)

the wipers are on the engine harness on a LHD car, but its really easy to de pin the connector, remove the wires from the old harness and put them in the new one.
the boost gauge is teed into the MAP/Boost/pressure sensor, the hard part here is that the stock sensor is a 2 bar, and if you use a different sensor the gauge will not read correctly
you could also run the NA volt meter

and then the other one is the wire for the coolant temp sensor, it goes from the sensor to the gauge, so no ecu at all, but its in the harness. this is the one i always forget!

WondrousBread

That's right, I forgot about that. The ECU doesn't interact with any of those electrically, but the wires are in the stock harness.

Check out https://www.aaroncake.net/RX-7/megas...tockWiring.asp

The guide is for a Megasquirt, but this part of the project should be the same.

GtiKyle

iTrader: (5)

Just to add some further useful information

https://www.aaroncake.net/RX-7/megas...tockWiring.asp

JerryLH3

iTrader: (11)

Mazda simply used what they call the "emissions" harness (the one from the ECU that everyone thinks of as the engine harness - even though Mazda calls a different harness the engine harness) as the best available path to incorporate wiper and cruise control wiring. They are in no way affected by the ECU, it's simply wires that got routed in the same harness. One could easily remove the stock wiring from the emissions harness and have them function or create a new sub-harness. There are two connectors by the blower unit that feed wires into the emissions harness for purposes of wiper and cruise control (and a few other things, injector power and possibly one or two other things I can't remember - consult the wiring diagram).