AcesHigh vtec trouble

I just completed the h23 to h22 swap but the vtec is still not wokring...after a lil reasearch i found out its my ecu. I now know that I need to get a vtec ecu. My question is will a 97-01 vtec computer (which i already have b/c it came w/ the engine) work w/ a 92-96 or will i need to get a 92-96 vtec ecu?

Well this question is basically for anyone who knows the answer but after readin Aces forum on the h23 to h22 swap (http://www.automotiveforums.com/vbulletin/t211027.html) i figure he would know for sure so i put his name in it just to catch his eye and hope he can help me out. if you know the answer tho please help

um...for starters, most people will probably recommend you get the p13 (4th gen) ECU because it is OBD-I, so they'll probably tell you your wasting your time with a 97-01.

Hey. As stated earlier, the 97-01 P5M ECU is OBDII, and will not work with your car without an adapater harness. If you took a look carefully at the wiring harness in your Prelude Si, you'll notice that it doesn't fit with the OBDII ECU even if you try to force it in.

You have two options here. One, buy a OBDII to OBDI conversion harness (which costs roughly a hundred bucks), or buy the OBDI P13 ECU from a 93-95 Prelude VTEC. Also make sure that the ECU you use matches with your transmission. I would recommend the P13 over the P5M because I'm not sure how well an OBDII to OBDI works. Second opinions anyone?

Hey. As stated earlier, the 97-01 P5M ECU is OBDII.


96-01 ;)


I would recommend the P13 over the P5M because I'm not sure how well an OBDII to OBDI works. Second opinions anyone?

I'd say go the P13 route too. I'll soon be switching over to OBDI, so i'll let you guys know how it goes.

AHA! The 96 OBDII ECU is, in fact, a P13. It has similar pinouts as the OBDI, but has connections for OBDII. If you compare it to a P5M, it is different. Bwahaha.

You've gotta be kidding me. :eek7:

Take it out and see, I believe it has a P13 sticker on it. It should say something like xxxx-p13-MT.

Well if you're right. I guess i'll just go with the obdII workaround.

ok heres the deal...i let a family friend who is a mechanic do the swap for me (first mistake) and he did say somehting about he could not get the wiring harness on the 01 ecu to match up w/ my car so he had to use the 93 non vtec ecu to get the engine to run. And he swears up and down that the vtec is kicking in, and i know for a fact thats its not especially after getting on here and doin the research that i have done. So my best bet would be to get a 93-95 vtec ecu? About how much would that run? i have found a few on ebay anywhere from $125-$250. Is any of that reasonable pricing? And does it matter if it is a JDM ecu or not?

and thanks Aces b/c right after i read that h23 to h22 conversion forum w/ pictures i ran out to my car and popped the head and found out that it is prewired for vtec :) lol

Yup, that's pretty much what I tried to say before the OBDII P13 thing. The wiring harness on your car (Prelude Si) is OBDI and cannot accommodate the 01 P5M (this is the ECU code for +97 ECUs). Your stock Prelude Si ECU is a p14, which does not activate VTEC. It also redlines at 6500rpm and has inappropriate fuel curves for an H22A.

Now, if you want to make the 01 ECU work, you need a conversion harness that attaches to your stock harness. This can convert the OBDI harness into an OBDII and you can then plug the P5M into it.

The quickest and least headache-inducing way is to just buy an OBDI P13 from ebay. Typical pricing is around 180 bucks, so anything you can get for under 200 is usually a decent deal. (Sometimes you get lucky on these). Since you are already prewired, all you do is plug it into the current harness. No fuss, no muss.

Good luck man.

these are the conversions you are talkign about right?
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33596&item=7929449870&rd=1

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33596&item=7929433410&rd=1

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33598&item=7929345768&rd=1

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33596&item=7929175655&rd=1

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33598&item=7929043951&rd=1

and if you were going to do the conversion which one of those would you use...i know the consensus will prolly be the cheapest one but im over my head here a little this is my first experience w/ anything like this and i know cheapest isnt always the best way to go

or do yall think im wasting my time and just need to go ahead and get the p13 ecu?

As long as it works, I would say the cheapest one. The OBDI p13 is tried and true, but I'm sure OBDII -> OBDI (and vice versa) would be okay. It's just I've never heard anyone report about it yet.

The OBDI p13 is tried and true, but I'm sure OBDII -> OBDI (and vice versa) would be okay. It's just I've never heard anyone report about it yet.

ok well since i already have the 01 ecu ive decided to get the conversion harness...ill post as soon as it is done to let everyone know how the obdII - obdI conversion went for future reference

well nearly a month later lol.....ive finally got the conversion harness and it will be going in this weekend...i went ahead and got one that has the wires colored and labeled instead of just one color so it will be easier to add a vtec controller in the future...basically all i have to do is unplug wiring from my ecu...plug that into the conversion harness and then plug harness into the 01 ecu. that should have vtec up and working properly correct? like stated before i am prewired for vtec so i can either plug up vtec solenoid to the connector or splice the wire, run the ground somewhere to the engine block, and splice the pressure switch wire that comes out near fuse box and connect to the pressure switch and im good to go when ecu is plugged up?

Yeah.. I believe VTEC is just two wires from the ECU. and Trust me, you'll know when VTEC kicks in. If you're not sure, it's not.

-J

well nearly a month later lol.....ive finally got the conversion harness and it will be going in this weekend...i went ahead and got one that has the wires colored and labeled instead of just one color so it will be easier to add a vtec controller in the future...basically all i have to do is unplug wiring from my ecu...plug that into the conversion harness and then plug harness into the 01 ecu. that should have vtec up and working properly correct? like stated before i am prewired for vtec so i can either plug up vtec solenoid to the connector or splice the wire, run the ground somewhere to the engine block, and splice the pressure switch wire that comes out near fuse box and connect to the pressure switch and im good to go when ecu is plugged up?

Yeah, besides those wires you need to run, you should be plug and play then.