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Pinout help

Practical Motorsport Wiring - Professional Level

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Afternoon All

I need some help with sensor pinouts. I started building new harnesses for my rally car nearly 2 years ago using the Club level & Professional motorsport harness courses. The plan was my club level car build using professional motorsport harness ideas, materials & training. I have never liked how the wiring harnesses in the WRX go thru the wheel arches and around under the front radiator support so I'm moving them all in behind the dash and using Deutsch connectors thru the firewall to newly built harnesses. I have previously been running it in club events until I damaged it at an event when I decided I am going to do all those jobs I have been "gunna" do. Changing where the wiring was run was one of them so I got into it & then life intervened!

Due to family issues & the whole Rona situation, (this bit is not a pity party! The Mrs cancer returning & us all dealing with it. Both daughters starting University, each a year apart & the costs of Halls of residence + the draws of everyday life, work & normal motorsport activities) my build got abruptly halted & over this period I have lost all interest in the car & barely looked at it. In the last couple of weeks I have started to kick back into it & now I'm finding I have misplaced or lost a bunch of stuff as well as needing details in the first place.

The car is a 93 Subaru WRX which is running version 5-6 wiring harnesses, Engine, Gearbox, Difs etc etc. Because I started it then stopped I have already potted sensors & no longer have the original harness. I don't want to rely on Dr Google to tell me which pin is which & goes to there because there can be differences. Can anyone tell me what pins go where on the following OEM parts?

2 pin Cam & Crank sensors

3 wire throttle position sensor

6 wire idle control valve. This has 2 rows of 3 pins which I believe the middle 2 are ground.


I am generally of the mind that spoon feeding info will result in failure in the end. But I can understand where you're coming from. So long as you're not skipping the fundamental way these sensors work and are just trying to save some time.


Haltech is full of these tech articles and they happen to have an EJ20 one.

The idle control valve will depend on what ecu your using, an H bridge doesn't need the middle pin ground wires.

I could be completely misunderstanding what you're doing though, If you are going to go straight from the ecu through a firewall bulkhead to the sensors it shouldn't matter the pinouts for the WRX sub-harness connectors..

Hi Tyson

I'm not sure what you mean by "spoon feeding"... I will check out the Haltech pages you mention thou. Thanks.

I am not wanting to shortcut & El cheapo the setup & it has to be done properly to keep it reliable because wifey was never a fan of me having the car for starters & only came around after a while because I was regularly driving it on the trailer in the morning and off in the evening! I do want to make the most out of what I have thou. Hell, building new harnesses, sealing wiring, buying expensive booting, potting sensors as shown in the course is by no means a shortcut!

Anyway. The ECU I will be using is a Link G4+ V3-4 WRX. Originally a plug & play unit which I am setting up as a standalone unit. Why? Because I have gone from the old V3-4 harnesses to the V5-6 harness, ECU (which I no longer have) eng, gbox, difs, everything. Wifey won't allow me to buy a brand new V5-6 Link ECU so if I ever want to get racing again I have to use this one. Hence the standalone set up for what should be a plug & play ECU. Apparently we have more important things than buying a new ECU for the rally car!

I have bought new ECU plugs & pins so everything will be brand new from the rear of the ECU forward. If I can figure out how to post a photo I will share that. The engine bay wiring will be all new, heat shrink labelled wiring in sealed harnesses with Deutsch fittings thru firewall. The issue now is I don't have the original manifold harnesses to show me what pin goes to where in the ECU. I have the ECU pin out from Link but have no idea which pin is what on the actual sensors!

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