Hello.

I purchased this 96 Prelude SI (Manual Trans) that had a H23 to H22a4 swap done. The chassis wiring was retained and a 97+ engine harness used, but spliced to a million pieces. The car is throwing 6 different codes for things like MAP and IAT sensors having high inputs. It is currently running off of the P14 (H23) ECU, but I was informed that it still shouldn't have these problems, just be less performance and no VTEC.

My question is, can I use a P5M (2000 Prelude H22a4 - Auto Trans) engine harness to get rid of this crap they put on here? Both setups have the external coil, I'm just not 100% sure of the compatability of the 96 OBDII chassis harness and the 2000 OBDII engine harness.

Any input is greatly appreciated. Burning way too much gas at the moment so need to get this bad boy fixed with these gas prices.

 

To my knowledge to many things will go wrong by using the P14. Injector sizes are different between the H22 and H23, plus adding the wiring splicing spaghetti you have there wont help either. So Id suggest starting by taking this setup to the closest 'stock' form possible. The auto tranny ECU won't be your best option either if your car is manual but you can give it a try since I think it'll work better than the P14. I've never done an auto tranny ECU on a manual to see the pros and cons. Maybe someone else can contribute on that part. Your wiring should be fine though. Give that a try, hope it helps. Good luck.

 

You should be able to "convert" that p5m to a manual by following the instructions here http://wikitest.pgmfi.org/twiki/bin/...2P5MAutoManual
I did the 4th gen auto-manual before I chipped and went neptune and it worked like a charm. BIG props to all the guys from pgmfi.org for all the great resources/knowledge they have put online.
GL
Mike

 

Been a while, ended up just buying a new harness from a junkyard.

 

Probably for the best. Good Luck!

 

Be aware there are subtle differences in OBDII emissions items in the 97-99 Prelude ECU's if you use one of those to drive it (slightly different components; in '98 they added I believe some kind of fuel pressure sensor and changed a couple other things around). With those ECU's you also generally have to have the correct Immobilizer system with it with matching keys, although there are some ways of getting around it. Also, if the motor is an a4 (OBDII), you need a '97+ ECU for the injectors, otherwise if you're using an OBDI ECU you need to swap injectors and put in a resistor box.

 

Am I the only person that read this as a question using a different harness, not ecu?

Sounds like a new harness did fix most of the issue, not surprising at all.

As mentioned, that ecu is not correct for those injectors or engine setup, if you can swing it, I would use an obd2 -> obd1 harness and get a tune with an obd1 based computer.

 

+1