killerken25

Ok, so my problem is that my 91 dx hatch is obd0.. the dizzy for the z6 head is obd1. I know that I can make my own harness, but im not 100% on which wire connects to what. Every tutorial i see online is for the 7 prong circular obd0 plug. if that was the case it wouldnt be too hard. but i have the 6 prong square obd0 plug. Does anyone know the wiring diagram for this? please help. Ill post a link of the only one i can find. but like I said, i have the square prong obd0 not the circular 7 prong obd0




http://img91.imageshack.us/img91/934/obdconvertes7.jpg

jlicrx

in order to use the Z6 VTEC head and get everything to work correctly, you will need to convert the car from DPFI to MPFI, by using a MPFI intake manifold and making all of the necessary DPFI to MPFI wiring changes to your DX engine harness - you will also need to convert it from OBD0 to OBD1 using an OBD0 to OBD1 ECU jumper harness, OBD1 P28 ECU and the Z6 distributor

FYI - you cannot use the Z6 distributor with OBD0 ECU

killerken25

i have a P28 ecu in the car right now. I purchased an OBD0 to OBD1 step up harness for the ecu.. i dont want to do a full Obd1 swap. right this second im not 100% worried about the vtec. I just need the car up and running for work. The MPFI is done i just need to wire the dizzy. I dont have time to order a Obd0 to Obd1 dizzy harness so i was going to make my own... like i had mentioned though, all the tutorials i find are for the 7 prong obd0 dizzy thats in the SI or an integra. I have the 5 wire, 6 prong obd0 adapter

24TEN

iTrader: (2)

The difference between the square plug and circle plug is two wires for an additional sensor that the MPFI distributor uses. The remaining 5 wires use the same colored wires. To use the Z6 distributor without buying a subharness, follow the write up for the 7 pin circular plug conversion to OBD1 and add the remaining two wires. Those two wires are originally a blue/yellow and a blue/green for OBD0, back track those two wires to the ECU pinouts on the MPFI conversion write ups and add them accordingly to the where they would be on the P28.

killerken25

so basically just do a normal swap but leave the 2 injectors for MPFI out. so run those through a resistor box straight into the ecu?

24TEN

iTrader: (2)

I'm specifically talking about the distributor plug, nothing to do with the injectors. You will have to address the fuel injectors as well unless you purchased an OBD1 jumper harness that includes a subharness for the fuel injectors.

killerken25

so at this point there is no such thing as just making my own harness?

24TEN

iTrader: (2)

That's what you'll end up doing, not an entire harness but basically just adding what you need.

If that jumper harness just converts your car to accept an OBD1 ECU then you are missing the MPFI conversion. With our cars, the MPFI conversion is the VERY FIRST thing you need to do before any kind of swap. Once this is taken care of, the rest is cake.

killerken25

well i just need the car to work for now. i dont need speed or acceleration at the moment. can i put my DPFI back on for now and leave the injector sensor wires off just to get back and forth to work then buy the sub harness and re-connect everything then?

24TEN

iTrader: (2)

You can, but the distributor would have to be bolted down the ghetto way because your old distributor won't fit correctly on the Z6 head. If you're ok with that then you should be just fine (can't say it will run flawlessly but it'll run). I've seen it done that way a few times, it's essentially just ran as the original DPFI setup but has the VTEC head attached.

killerken25

what would you suggest to bolt it down with? i tried using the bolts and all 3 dont fit. the top one is too high and the bottom ones are also a bit higher. my first thought was zip tie. but that probably wouldnt hold on enough to keep it in place.

24TEN

iTrader: (2)

That's exactly why I say the "ghetto" way. Some people run just two bolts, others enlarge one of the slots, while others still will even cut a leg off completely. If it were me in your exact situation, I would remove the internals from both distributors and see if it's possible to swap them over temporarily (not sure if that's possible to be honest, but I've done the swap from a Z6 housing with Y8 internals and vice versa). I'm not going to lie, my daily has it's distributor only held down by two bolts BUT I'd never recommend doing that for anyone. Do as I say, not as I do LOL

killerken25

yeah ide rather just do it right... im just gunna put the stock head back on for now until i get the rest of the parts. might just do a full obd1 conversion.