How to bypass the injector resistor box?

Jack · Post by **Jack** » Tue Jul 05, 2016 2:34 am

I'm doing a H22A7 (ATR) swap into my 4th gen. The ATR uses high impedance injectors, the Prelude uses low impedance. Hence the Prelude has an injector resistor box mounted on the bulkhead that looks a lot like this:

I'm led to believe that I can't just leave it unplugged, and I have to cut and splice the 4 black wires into the red one? I've done quite a bit of research on this over the last few days, and can't seem to get a clear understanding of what I need to do? I'm not electrically minded at all, so pictures are very welcome!

Thanks.

Post by **Merlin** » Tue Jul 05, 2016 8:48 am

The best way is to use your 4th gen injectors, especially if you are using a 4th gen ECU.

Still, if you are using a 5 gen ECU with a conversion harness you would still be better off using the 4th gen injectors, loom, dizzy, alternator etc...

mercutio · Post by **mercutio** » Tue Jul 05, 2016 4:54 pm

The atr injectors have a better spray pattern but other than that there isnt a lot of difference easier to use the 4g injectors

Post by **NafemanNathan** » Thu Jul 07, 2016 9:27 pm

http://www.ludegeneration.co.uk/post9863.html#p9863

Jack · Post by **Jack** » Fri Jul 08, 2016 2:45 am

mercutio wrote:The atr injectors have a better spray pattern but other than that there isnt a lot of difference easier to use the 4g injectors

Although the engine has high mileage I'd like to give it the best chance of producing decent reliability and power, the engine is designed to work with the ATR injectors so I'd rather stick with them really. Also don't fanc opening up the injector holes in the inlet as I'd no doubt find a way of drokking it up

NafemanNathan wrote:http://www.ludegeneration.co.uk/post9863.html#p9863

So you literally just cut the plug off, splice all the wires together, remove the box and plug the plug back in? Awesome!

Post by **Merlin** » Fri Jul 08, 2016 9:26 am

What ECU are you using?

Jack · Post by **Jack** » Sat Jul 09, 2016 12:26 am

Merlin wrote:What ECU are you using?

To get it running, I'll be borrowing my mates Hondata S300 (mapped in a H22A7 DC2 with intake and exhaust, like my lude) so the map should run it fairly well. Once it's up and running though I'll be using my chipped P28 and getting it mapped on Crome.

Dino · Post by **Dino** » Sat Jul 09, 2016 8:25 pm

I guess thats Rorys DC2 youre on about?

TheHondaTuner · Post by **TheHondaTuner** » Tue Aug 30, 2016 2:48 pm

So the plugs on the injectors are different. And they just need to be replaced? Same cabels just different plug? Plus the Resistorbox wich looks very easy.
What would happen with stock ECU?

Post by **Merlin** » Tue Aug 30, 2016 3:29 pm

TheHondaTuner wrote:So the plugs on the injectors are different

I don't think they are. The only difference is that the dissy and alternator plugs differ between OBDI and OBDII. Really, for simplicity, you don't want to be mixing OBDI and OBDII bits. When I put an engine from 5th gen (OBDII) into my 4th gen (OBDI) I took everything off the engine that made it OBDII and replaced it with OBDI parts, and used a 4th gen P13 OBDI ECU.