Hello, wondering if anyone can help me, I’ve put a 1994 h22a2 into my 99 civic coupe ej6, I’m running a p28 ECU with the adaptor harness, I’ve used my original engine harness and adapted it to work with the h22a2 and the chip just has a base map on it.

Now everything works as it as it should and the cars been driving issue free for 6 months now (touch wood). The only issue is that the tach has never worked since I did the engine conversion. Worked fine when it had a d16z6 motor in it.

now I’ve read about the adaptor harness’ etc being funny but mine checks out alright, although when my alternator is unplugged and disconnect from the car my tach works??

If anyone one can help me out with a way to fix this (get the tach working while the alternator is connected) it would be much appreciated. I’m from the UK and I know most people on here are US so sorry in advance if I’ve used some different words but I’m trying my best. Thank you in advance, Dan

 

0bd2b gets its tach from an 0bd2b ecu. You'll have to get a signal from the dizzy

 

Connect the blue/silver banded tach test wire near the firewall on the driver's side to the yellow/green ICM wire at the distributor.

 

Thanks it I’ve tried both of these, done a lot of research etc, I know where the tach comes from and where it needs to go it just won’t work when the alternator is charging the car 🤷*♂️

 

alternator charging the car has nothing to do with the tach signal, you have some wiring issues you need to sort out.

 

How many wires are in your alternator plug... 3 or 4 ??? What pins at the ECU do they terminate ??? List wire color/pin location please.

 

Thanks for the replies everyone, it’s looking like I’ve made a writing mistake somewhere so I’m gonna take my harness out and go over it, Thank you