OBD1 to OBD2 'Blue Top" swap - Honda Prelude Forum

Paladin · 01-12-2013, 05:21 PM

Ok, so I'm newly registered, but I've came to the forums from time to time looking for answers and I've been doing fine until now.... I'm stumped. lol

I have a H23A1 that I locked up almost a year ago, and now I'm finally getting around to fixing it. I'm getting a H23 VTEC Blue Top with the ECU and wiring harness. I know it's OBD2 and my prelude is OBD1. I'm just wondering what all problems I'm going to run into before I put in the engine, or what all else I need to get so everything will match up?

Paladin · 01-12-2013, 05:35 PM

Also, I'm getting a S2000 gauge cluster for my Prelude and I'm not sure if the AP2 cluster will plug in fine or if I need to get an AP1 cluster....

Chett says · 01-17-2013, 07:47 AM

Are you going to switch the blue top to OBD1 or leave it as OBD2?

Paladin · 01-19-2013, 10:44 PM

I can do it either way. I'm getting the ECU and wiring harness with the motor, but im actually not sure what would be easier to do, or what would be better for the engine?

TypeT · 01-20-2013, 02:47 AM

obd1 can be tuned if youre thinking about building your engine more...

of course if you get "custom" map that would be better than stock

indylude18 · 01-20-2013, 07:16 AM

The original ECU for that engine is from an automatic accord, it won't work well in a prelude. You'd be better off using a p23 or p72.

Paladin · 01-21-2013, 03:15 AM

ok now you're going over my head. What is a p23 and a p72? Are those different types of ECUs?

indylude18 · 01-21-2013, 08:07 AM

Yes. They are OBDI ecus that can be chipped and tuned.

Paladin · 01-21-2013, 05:19 PM

oh ok, so the ECU in mine now wouldn't work right for the engine i'm trying to put in? I need to get a p13 for the h22?

Paladin · 01-21-2013, 05:22 PM

i meant the ECU from my h23a1 wont work the same for this blue top? and i have to get the one for the h22?

TypeT · 01-21-2013, 11:10 PM

Quote:

Originally Posted by Paladin

i meant the ECU from my h23a1 wont work the same for this blue top? and i have to get the one for the h22?

your old h23 isnt even vtec engine!

and h22 ecu wont work perfectly either, its not designed for h23 vtec so if you dont have ecu with that h23 vtec engine you have to go with chipped ecu and get it tuned with custom map

Paladin · 01-23-2013, 07:49 PM

I'm getting the ECU that goes with this engine, but it's for an automatic.

indylude18 · 01-23-2013, 10:09 PM

The Accord ECU will not work....that's why you need a chipped OBDI ECU.

I got mine from here: Phearable.net - Electronic Fuel Injection Tuning Solutions - Hondata, Neptune, Crome, Ectune, AEM, Honda Tuning, Widebands, Fuel Pumps, Turbos, ECU Chipping, Chipped Ecus They already have an H23 bluetop basemap on file. It runs rich, but it runs.

schmitty915 · 01-24-2013, 06:04 AM

Quote:

Originally Posted by TypeT

your old h23 isnt even vtec engine!

This.

Your goal should be to go OBD1 so you can properly tune the ecu.

You either need to read up on how to adapt the stock H23A1 harness to accommodate the H23A or try to find an OBD1 H22 harness.

Is your car an automatic or manual stock?

Honestly, you really need to do your research.

Quote:

Originally Posted by TypeT

and h22 ecu wont work perfectly either, its not designed for h23 vtec

I ran my H23A off my p13 for a month before I could get it tuned and it runs fine but as a temporary solution only.

OP - If you want an idea of how to run it properly, this is how mine is set up:

Stock: 94 H22A1 (manual transmission)

Swap: H22A1 harness, H22A1 distributor, H22A1 injectors, Professional Products 68mm throttle body (H22A1 throttle body will work), Euro-r intake manifold (although stock H22A1 manifold will work), Neptune chipped/tuned p72

Quote:

Originally Posted by indylude18

The original ECU for that engine is from an automatic accord, it won't work well in a prelude. You'd be better off using a p23 or p72.

I think you meant p28.

Paladin · 01-25-2013, 05:36 PM

My car is a manual. I've found a chipped p72 ecu on ebay that can be custom mapped to my h23, but will i still be able to use the h23a1 harness just fine or what?

schmitty915 · 01-28-2013, 08:08 AM

You'll have to wire in VTEC if you're using the H23A1 harness.

Look up write-ups on H22 swaps to learn how.

Oggi · 02-04-2013, 09:22 PM

hello,

I have a 1993 prelude automatic and i did a swap to a 1998 h22a with a manual lsd tranny. I was just wondering if i have to remove anything and what i have to change. I am still using the auto harness and the cluster is auto too. I feel like some power is missing and i was just wondering if i need to change anything, like the ecu i think it might still be with the same one in there from the last auto engine.

Can anyone help?

Paladin · 02-18-2013, 11:32 PM

Ok, so, I've gotten everything to do my swap. I've got an ECU that has been chipped and mapped out to the Bluetop engine. I've gotten the VTEC sub harness to add to my wiring harness. I have both tech manuals for my Prelude; the Service Manual and Electrical Troubleshooting Manual. I'm starting the swap this coming weekend with some of my good buddies. I'm going to try to take some good pics and post them up as I get the chances. Wish me luck!

Paladin · 02-28-2013, 07:04 PM

Paladin · 02-28-2013, 07:25 PM

So, instead of dropping it into my car right away, i'm going to hold off and let my buddy build it while I'm on deployment. When I get back in Oct., we'll drop it in then.