Fith gen H22A7 swap questions

TonyG · Post by **TonyG** » Thu Jul 23, 2020 11:18 pm

Hello everyone, I'm in the process of swapping a h22a7 Into my car, My car is obd1 and the engine is obd2 so I was just curious as to how the wiring looms compare? I will be running on an obd1 ecu and I have the obd1 engine harness there from the old engine as well if I need to adapt the plugs, Thanks.

Post by **Drax** » Fri Jul 24, 2020 8:55 am

AFAIK using the odb1 loom will be your best bet, the only issues i can think of are some wires will be adapting to plug into the a7 peripherals (easy to do) and the injectors will either need to be odb1 or if you want the atr ones you can reverse the impedance of the injector loom by soldering all the injector resistor wires together.

i thin you'll need an odb1 dizzy as well as AFAIK the odb1 doesnt have a plug for the a7 cam/crank sensor, i cant remember which it is. im sure other people will correct me/add on other items as well

Brozilla · Post by **Brozilla** » Fri Jul 24, 2020 11:48 am

Drax wrote: ↑
Fri Jul 24, 2020 8:55 am
AFAIK using the odb1 loom will be your best bet, the only issues i can think of are some wires will be adapting to plug into the a7 peripherals (easy to do) and the injectors will either need to be odb1 or if you want the atr ones you can reverse the impedance of the injector loom by soldering all the injector resistor wires together.

i thin you'll need an odb1 dizzy as well as AFAIK the odb1 doesnt have a plug for the a7 cam/crank sensor, i cant remember which it is. im sure other people will correct me/add on other items as well

Doesn't 4th gen have a resistor box? If so, he could just unplug it and use a cap from 5th gen to short the wires instead of soldering them.
There will indeed be some issues regarding various connectors, most important one being the distributor.
H22A7 distributors do not have an option to mechanically adjust ignition timing and you will need that since you are using obd1 ecu instead of H22a7's ecu. I would suggest using a5 distributor to solve that problem. Probably easiest solution is to swap existing obd1 distributor internals into h22a5 distributor case.

Post by **Vtecmec** » Fri Jul 24, 2020 2:55 pm

Keep the OBD 1 loom, injectors and dizzy, swap new engine. No messing around required.

h10ndr · Post by **h10ndr** » Sat Jul 25, 2020 12:29 am

Vtecmec wrote: ↑
Fri Jul 24, 2020 2:55 pm
Keep the OBD 1 loom, injectors and dizzy, swap new engine. No messing around required.

That's what richy did when I went A7 in the lude. He kept the lude intake as well and injectors

Post by **Vtecmec** » Sat Jul 25, 2020 6:58 am

Nice to see your still around Tim.