WheelPowerRacing

1994 Civic EX (D16Z6 SOHC VTEC removed)
P72 chipped ECU (Knock sensor disabled)
LS/VTEC with GSR head & stock intake
1994 stock GSR wiring harness P72

Here is my problem. I know the IAB to ECU wire is the pink with blue stripe (ground). The wire terminates to the ECU at A17, no problem there, empty spot, inserted wire/connector. The problem is out at the firewall. I assumed that the other end of the A17 ECU wire would terminate in an empty spot on the passenger side connectors. However when I trace & ohm out the IAB pink/blue stripe wire in the motor harness, it goes to the connector on the drivers side. That spot already has a wire in it. ( I think it goes to the evap purge on the d16z6 harness) Anyone have any experience with this? I can d-pin the wire and replace it with the ECU A17 wire, but want to make sure before I create more problems.

P.S. since I am using a p72 stock harness does the yellow/black (+12v) on the IAB's already splice into the yellow/black at the jumper connection

WheelPowerRacing

help???

rick_rabies

this is what i did. find a type R style intake manifold and put it on. problem solved they are $50 around town and its lighter and you dont need that bracket underneath the mani so things are easier to work on

WheelPowerRacing

Easy fix, but I want the dual intake because I believe it to be an advantage in Auto-X.
After spending the last several hours comparing my GSR and D16z6 OBD1 harnesses I have reached the following conclusions (which may be incorrect):

1. The GSR harness has a separate plug (pass shock tower) for the evaporative purge. The d16Z6 chassis harness uses the termination points for the GSR IAB's for its evaporative purge.
2. The easiest fix would be to:
A. de-pin ecu A20 (Evap Purge) and place it on ecu A17 (IAB's). Then I do not have to move the IAB termination in the engine compartment or harness at all.
B. Use a jumper connector to connect A20 (Evap purge) to the GSR engine harness connector red wire that connects to the evap purge at the passenger shock tower. I would unplug the knock sensor wire (not used) and plug the red evap wire into its hole. Then use the wire jumper wire on the chassis side.

Would this work? Does the evap purge being disconnected fault the ecu? On a dedicated race car would you remove the Evap solenoid and canister and if so what would you do with the line going to the fuel tank?

omgwtfbbq

hack off the IAB plug on the harness side....send your own wire through the firewall to A17, and tap your other wire to a 12v+ (I tapped mine into B something @ the ECU, i think it was a black/yellow wire).

IABs opened on time, every time....didn't have to worry about all this shock tower BS.

Also, keep your EVAP. Wire it the same way as the IAB since your civic shock tower doesn't use the same 2 pin plug that your gsr harness has. Wire the red to A20, and the other wire to the same place that you are sending the secondary IAB wire to (the 12v).

I did this same swap in the same car that you are doing....and this is what I did, and my car had no CELS and never gave me any problems.

omgwtfbbq

I just read my post and it sounds like a bunch of jumble.

anyway, I'm basically trying to say that you are having trouble trying to run everything through the stock harness. I avoided this problem by cutting off the connectors and running it my own way, straight to the ECU.

WheelPowerRacing

Thanks for the info. I just hate hacking and splicing. Everywhere there is a splice is an increased chance of failure and increased difficulty troubleshooting. Even when soldered. The factory pin connections last for hundreds of thousands of miles. The last thing I want is to pay entry fees, haul the car 2 hours and then spend the day under the hood while at the track. Trying to spend the time and effort now doing it the best way. But from the modified Hondas I've run across so far, twisting the wires together and black tape is par for the course.

omgwtfbbq

I've worked with electrical for years, so I had the confidence to cut the connector off of my harness, and wire it straight to the ECU. I soldered everything and rechecked all my work after. no problems.

In fact, I had to recently resolder an entire firewall side harness into an integra engine bay (some genius cut all the connectors off of the shell). when it was all said and done....not one problem after. Car ran great, no CELs, and still hasent given one problem. I guess it depends on your skill level.


anyway, if you know what you did to your car, and you run into problems later, then you know where to look to fix it. If you are unsure of a connection, test it. if it doesnt test out right, redo it.


simple.

WheelPowerRacing

For anyone looking for guidance on this issue, I did what I stated in this post and it worked perfectly. All factory spec connections, no splices to fail. Easy and quick. My P72 engine harness is unmolested, a plus if I resell it in the future