vtec wiring questions AGAIN!

so i made my wiring harness and ran it throught the firewall and have the wires waiting to be inserted into the ecu harness here is my questions/problems.
-I took the plugs out of the ecu harness of OBD-0 harness will they not insert into the OBD1 harness?
-Where do these 3 wires go i searched and looked at teg tips i see 4 differences between the pr4(took out) and the p61 (goin in)
- A4 vtec spool solenoid
- A20 purge control solenoid
- D3 knock sensor
- D6 vtec pressure switch
i know the knock and the vtec pressure switch but which one do i put the oil pressure wire into A4 or A20

  • Also does anyone have a picture or diagram of the plugs so i know where they go cause i have a chilton not a hanes and it really doesnt show any ecu wiring stuff, pretty much A20 means nothing to me cause i have no clue what plug that is or where that spot is.

-Also on a sidenote if i dont run the knock sensor plug right now will that cause some problems other than the check engine light.
thanks again



OBD-0 pins will not “snap” into an OBD-1 Harness. You may bbe able to get them to work, but you run the risk of having the pins come out every time you push the plugs into your ECU. You need OBD-1 pins or OBD-2 pins. They will “snap” into the harness.

Put the wire from the VTEC Spool Solenoid into A4.

Put the knock sensor wire into D3

Put the signal wire from the VTEC Oil Pressure Switch into D6.

Put the ground from the VTEC Oil Pressure switch to chasis ground.

You don’t need to worry about anything else. The car will run great. If you don’t wire the knock sensor right off the bat, you will get a check engine light unless you are running a chipped P61 that eliminates the knock sensor (most do).

As far as counting what pin goes where it’s really simple. Count from the left to the right of the ECU when it’s upright. Far left (Largest plug) is plug “A”, next over (smallest plug) is “B”, and then it skips right to (medium size plug) “D”. Pins start from 1 on the top left and 2 being right under it, and then 3 being next to 1, and 4 being under 3…and so on and so forth.

Somthing like this (This being plug “A” on the ECU or looking into the back side of the harness where the wires plug in


1_3_5_7_ 9_11_13_15_17_19_21_23_25

thanks dan
you know your the only one who ever answers any of my questions.
anyways thanks again

oh hey while i got you here dan i remeber you saying you had old harnesses laying around would you be able to sell me about 3 obd-1 plugs from an old harness, if not i will hit up the yards.

Justin, I have some harnesses floating around, but no OBD-1 harnesses at the time being. I may have a few OBD-1 pins though. What do you need off the OBD-1 harness? Many of the plugs are the same between OBD-1 and non-OBD.

well you just told me i needed some obd1 pins to snap into my obd1 harness was wondering if you had any of those around, i have a 93 ls. I pulled pins from an obd0 harness and used them in my wiring harness so i just need 3-4 obd1 pins to solder on in the obd0 pins place, no hurry though, i am up at WSU right now and the car wont be driven till early may so keep a heads up for me
thanks alot

hey did you gather up any obd1 ecu pins yet? i am driving the beast again and the obd0 pins just dont want to cut it. thought i would check with you before searching for a junk yard.