MPFI and Vtec wiring

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MPFI and Vtec wiring

Post  ShopJRD.com on Thu Jan 17, 2008 1:54 pm

Hope this all helps. its info I have picked up over the years.

When you do a motor swap into your EF you are most likely going to have to do some wiring. If you have a DPFI model (dual point fuel injection) you will most definately have to do a DPFI => MPFI conversion, and if you are putting a VTEC motor in there you will have to wire for VTEC. It is a lot easier than it looks or sounds. Throughout all this i am assuming you are staying OBD0.

When wiring please use solder and heat shrink tubing. It makes your wiring last longer and look MUCH cleaner. If you cant solder I think you should put off this wiring job until you can (or get one of your soldering friends to do it).

MPFI: what to do.

You are going to use your stock engine harness as the base of your "hybrid" harness. Not the engine harness that came on the motor, an Si or Hf harness (unless your car is an Si or Hf), or a B18a harness (not even with a B18a). This is a common misconception. People always want to use a stock MPFI harness. The problem is that it doesnt work unless you want to repin the connectors that connect it to the car harness. IMO that would be a lot of work.

The engine harness you got with your motor is going to be used for parts. You need the injector plugs (I cut the wires as far back in the donor harness as I can so I dont have to do any lengthening), the injector resistor plug (dont even cut it off the injector plugs, just trace it back), and the distributor plug. In addition to the plugs off the donor harness you need an injector resistor box. This box can come out of any OBD0 civic or integra.

Now that you have all the stuff lets get to wiring. I like to do all the engine harness stuff first so thats how I'm gonna write it. Keep in mind that this is MUCH easier to do with the motor out of the car.

Engine:

* Connect the yellow wire on the DPFI harness to the brown wire on the injector plug for the #1 cylinder.
* Connect the red wire on the DPFI harness to the blue wire on the injector plug for the #3 cylinder.
* Run the red wire on one of the injector plugs to ECU pin A3 for the #2 injector. I usually like to run this wire into the pass side engine-to-car plug (big white one) then do the other side when I do the interior wiring.
* Run the yellow wire on one of the injector plugs to ECU pin A7 for the #4 injector. I usually like to run this wire into the pass side engine-to-car plug (big white one) then do the other side when I do the interior wiring.
* Connect the 2 yellow/black wires on the DPFI harness (from the old injectors) the yellow/black wire on the injector resistor plug.
* If you cut the injector plugs off the injector resistor plug then you have to reconnect the red/black wires on the resistor plug to the injector plugs.
* De-pin the Distributor plug from the MPFI harness (except the blue green and blue/yellow wires. Cut those as you will use them later) and WRITE DOWN which color wires went where. Then de-pin the DPFI distributor plug and put the MPFi plug on your DPFI harness. Make sure the colors are the match up to what you wrote down. There are 2 white colored wires and they can easily be mixed up. So make sure the white wire that is a "loner" (not in a group of 4) is a "loner" when you re-pin the MPFI plug (I need some pics, heh).
* Run the blue/green wire on the dist plug to ECU pin C1 for the cylinder position sensor. I usually like to run this wire into the pass side engine-to-car plug (big white one) then do the other side when I do the interior wiring.
* Run the blue/yellow wire on the dist plug to ECU pin C2 for the cylinder position sensor. I usually like to run this wire into the pass side engine-to-car plug (big white one) then do the other side when I do the interior wiring.
* Lengthen the TPS and IACV wires. Also, you need to swap the green/white and yellow/white wires on the TPS plug as the MPFI throttle bodies rotate in the opposite direction of the DPFi ones.
* There will be 3 plugs of the exact same type which are easily mixed up. These plugs are for the IACV (blk/yel and blu/yel), the IAT (little white sensor on the IM; orange/yel and grn/white), and for some DPFI sensor (blk/yel and orange). The plug with the blk/yel and orange wires is NOT used. You can cut it off or let hang or whatever.

ECU plugs:

* Connect the orange wire on C1 to pin B10. You can either de-pin C1 and swap it over or cut C1 and solder it onto a wire you put in B10.
* Connect the white wire on C2 to pin B12. You can either de-pin C2 and swap it over or cut C2 and solder it onto a wire you put in B12.
* Run a wire from C1 to the blue/green wire on the dist. If you ran the blue/green wire into the pass side plug then this is very easy.
* Run a wire from C2 to the blue/yellow wire on the dist. If you ran the blue/yellow wire into the pass side plug then this is very easy.
* Cut the wire at A3 and run a wire from A3 to the red wire on the #2 injector plug. If you ran the red injector wire into the pass side plug then this is very easy.
* Cut the wire at A7 and run a wire from A7 to the yellow wire on the #4 injector plug. If you ran the yellow injector wire into the pass side plug then this is very easy.


VTEC wiring.

If you gotta b16, b18c, or ls/vtec and are running a PR3 or PW0 you have to wire for VTEC. This is VERY easy. The best thing to do, IMO, is to make a new harness just for the VTEC wires. I usually find a 4 or 6 pin male/female plug combo from one of the harnesses that I have and go from there. If you dont have any harnesses floating around then a junkyard will definately have one that you can pull plugs from. In the cars I've wired this plug combo resides on the clip (yes there is even a clip for this plug. They were thinking of us swap guys!) right next to the big white pass side plug. What you do is run the wires from the ECU to one end of the plug (the end that clips onto the clip), then make an engine harness with all the wires converging into the other end of the plug. Heres a pic of that "VTEC plug."
the VTEC plug is the small one under the big one.

Engine harness.

* Hook up the VTEC solenoid. Its a green wire with a single connector on your OBD0 VTEC harness.
* Hook up the VTEC oil pressure switch. It is a 2 pin plug near the VTEC solenoid. One of the pins is for ground (the black one) and the other goes to the ECU.
* Hook up the Knocksensor. This is on the back of the block and has a plug exactly like the oil pressure switch except it only uses 1 of the 2 wires in the plug. The knock sensor wire is supposed to be a shielded wire so use a shielded wire.
* Hook up the 2nd O2 sensor. Yes you need it. It is also supposed to be a shielded wire.

Pic of the VTEC solenoid and the oil pressure switch:
read the red writing, f00

Car harness.

* Run the wires from the ECU to the plug that I talked about earlier and make sure the wires match up.

Pin Function
A8 VTEC solenoid
B5 VTEC oil pressure switch
B19 Knocksensor
C8 Second oxygen sensor

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Re: MPFI and Vtec wiring

Post  BOWERS on Thu Jan 17, 2008 2:04 pm

Very good info CJ!
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Re: MPFI and Vtec wiring

Post  Kries on Thu Jan 17, 2008 2:06 pm

BOWERS wrote:Very good info CJ!

x2!!
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