this is probably a dumb question but... white plug behind the glove box

[s13point5]

so i as doing some searching trying to find out what my cold start problem is. seems like i need to hook up the orange wire from the white plug on the car side to pin 43 on the RB25 ecu. anyways i go out to the garage to smoke a cigarette and decided to take a quick second to find the plug they were talking about. i seem to have found it. but then i pull my ECU out and i see the white male connector on the harness that goes to the white plug. its not plugged in obviously. but my car runs fine without it. i wasnt told to plug connector in either (but i wasnt told to NOT plug it in). i dont know if im suppose to plug that connector up because my car runs perfectly fine (just has a hard time starting and randomly has a high idle). so what do these wires control that go to this white plug? im somewhat hesitant to plug it in because i dont know what it controls. there is alot of wires on this plug. like i said, only reason im not sure if im suppose to plug that in is because my car runs without it plugged up. also i think i read somewhere that the wire for the tach goes to this plug as well. my tach doesnt work BUT when i first started my car, the tach worked. after i unplugged the ECU one time to do some trouble shooting, the tach stopped working

[mello88]

The orange wire is not off the white plug, it's the orange wire off of the brown plug. It way up above the glove box zip tied to the dash bar near the vent... Goes to pin 43 on the ECU, which goes to a white 16 pin plug on the ECU side. The other pins on that same plug are for the speedo, tach, CEL, and other random dash/instrument functions. Crack your FSM open to the ECU pinout page, trace each of the wires back to the ECU connector and find out for yourself what they do.

[BoostFab]

right behind the glove box (to the right): on a 89-90 s13 the white plug is the same as the brown plug in 91+ s13

[s13point5]

i thought it could be either brown or white? i didnt see a brown plug up there when i looked.

[s13point5]

i didnt see boostfab's post when i posted lol.

[BoostFab]

you are on the right track. word of advice, don't wire in anything you are not sure about, you can easily fry something.

KA Wire Color:................................Purpose:

Yellow / Red stripe....................Tachometer signalYellow / Green stripe.................Speedometer SignalBlue / Black stripe......................Water temp signal

[s13point5]

you are on the right track. word of advice, don't wire in anything you are not sure about, you can easily fry something.

KA Wire Color:................................Purpose:

Yellow / Red stripe....................Tachometer signalYellow / Green stripe.................Speedometer SignalBlue / Black stripe......................Water temp signal

thats why im hesitant to plug that in. but my wire guy has my harness setup to look like i am suppose to use that plug tho. my tach doesnt work but my speedo does. and im using an aftermarket water temp gauge.

[s13point5]

any s13 rb25 owners have this plug actually connected?

[l0nestar]

any s13 rb25 owners have this plug actually connected?

For me (Brown plug / DOHC chassis)Brown plug un-plugged - No tachBrown plug plugged-in - Tach!

I don't recall if I had speedo without Brown plug connected.. If I remember correctly, it would act as though the car was 'in-gear' and increase the 'speed' displayed on my HUD while the engine was free-spinning (not moving) I don't think there was even a driveshaft hooked up at the time, lol!

I'm not using the stock coolant temp gage - I went Defi, so I can't help you there.

Boostfab,Thanks for the quick 'diagram'!

[s13point5]

i plugged it in. my tach and stock temp gauge works now. car doesnt have much trouble starting after sitting for 12 hours or so anymore. the only bad thing that happened after plugging that plug in was my check engine is now on.

[l0nestar]

I don't have CEL, but I do have BRAKE and Battery (over / under charge?) lights illuminating -- everything is good though. my volts are around 14 constant.

[s13point5]

im not getting those lights. actually im getting randomly the seatbelt and door open dash lights. plus the chime for the seat belt keeps going off.

anyways, is lsauto the only way to get my tach calibrated? i tried to do a search for 10k resistor thing but i didnt find much and what i did find kind of confused me. anyone have a diagram or something i can look at to do that mod? and ive noticed since my speedo isnt calibrated, its reading half of what im going. im wondering if i put my 180 speedo in which reads in KMH, it would be closer to what im actually going and i can just look at those numbers as if they are in MPH