HAC sensor wiring diagram.. HELP plz..
 

I think they only put this HAC(High altitude sensor) in 86 and 87 supras with the 7MGTE engine... I had to send new wires from my throttle body strait to the ECU and it still hasn't been running right. Now I just found out that the HAC sensor gets an input from the throttle sensor. I know that what ever that wir is it's not hooked up now.

So what I need is a wiring diagram for this HAC sensor.

The GTE wasn't available in any '86 models (not in any '86.5 models either ;) ). The HAC is present in ALL KVAFM equipped 7M's, it's just been moved inside the ECU on later models. You need a TSRM or TEWD from '87 or '88. Below you'll find links for '87. It has the TSRM wiring diagrams (Not as pretty, but they work).

http://www.turboninjas.com/mk3supra/

I don't recall the HAC getting a THA signal at all. The HAC is a little black box mounted on the back side of the lower glove box support. It's nothing more than a MAP sensor.

I sold all my pre89 manuals some time ago as I seldom needed them for anything which isn't covered in the '89.

Worried about V or VC
 

The HAC dosn't get THA, i'm worried about V.. I'm guessing that V is the same as VC.

Is there any thing else that goes on VC?

The EFI TSRM doesn't show what wires specifically go to the HAC sensor I know E2 is the ground for all sensors but V doesn't even show up on the ECU pin out that I have.

I put this Diagram together and this is my guess. The second diagram (with only the HAC sensor) Came strait from the manual... Just to show that somthing from the HAC does hook in with the throttle sensor and the Air Flow Meter..

Vc is just a constant voltage signal provided by the ECU to certain sensors... it's a power supply line for lower power devices. Should be around 4.8v with load.

Thx
 

Okay... that makes sense for the HAC to need a negative and a positive to come up with its signal...

Thanx

Are you trying to troubleshoot it or bypass it?

EDIT: If you're looking to bypass it, here's my site with info on MAFT Pro installations and as such info on bypassing the HAC sensor: http://www.fadingworld.com/CRE/Autom...ra/Electrical/ See the GTE install wiring diagram for SD. It's quite easy but for most it's easier to see it than just read it.

I'm going to make a new engine harness and I'm just trying to gather a diagram for the '87.. do the newer ECU pin outs have the same exact names as the one for the '87 and they are just arranged differently?

Look at the diagrams on my site for the '87 - '88 pinouts and cygnusx1 for the '89 - '90. Most are similarly named.... I usually buy an old harness and replace the wires one at a time. Have fun, it sucks!