h22 swap into h23 prelude

jam05pr

Member
Hello everyone,
This is my first time writing in this forum. I just had a question about swapping a JDM H22 Obd1 into my Obd 1 H23 prelude. I know that it is a simple swap but I was wondering if I could use my h23 wiring harness and what i would need to do to it to make it work. The motor didnt come with a p13 ecu so I was wondering if I could use my p14 and just add a rpm activated switch. I also hear that I would need to change the jdm fuel rail, is this true? If anybody can help with this I would really appreciate it. Thanks.
 

phunyguy

Junior Member
Don't quote me on this.... im still learning myself. i heard of problems with a p14 running an h22... problems with fuel mixtures... as far as the fuel rail and such i think they are the same. wiring i have no clue though....
 

H22AdelSol

Senior Member
If you wanna run your new h22 without VTEC you can use your p14. The air/fuel ratio of the p14 is not the same as the p13. Go get the p13.
 

tab

Super Moderator
Keep your JDM fuel rail. Use a P13. Run two wires to the new ECU for VTEC, and one ground. It is a simple swap. If you get an H22, come back and we will help.
 

imprt92

Member
i just did this swap! the fuel rail you will need to change if your new motor is jdm . use the one from your h23. the wiring harness is the same other than the dist. the h22 has internal coil so your p14 wont run it! unless you take the coil and dist from your h23 but i did this and mine isnt runing right! im waiting on a p13 hopefully this will correct the problem. oh use the injectors from the 22 when you change your fuel rail. if you get a p13 you should be able to use the h22 dist , but i havent figured out the wiring i think you will need to splice some wires. let me know how it goes and i will post again if i come up w/ anything that might help you.
 

tab

Super Moderator
You can use the JDM fuel rail. I did. I just lengthened the fuel line slightly to reach the other side of my motor. If however, it is easier to switch the fuel rail, then by all means do that.

Internal coil only needs one wire to run. Piece of cake. Look through the other threads.

Your swap is the simplest to do. Thank god someone got the right OBD engine for their car!!!!

Two VTEC wires, and a ground. One wire for your coil. Maybe switch the fuel rail. Use your stock harness and vacuum line stuff. You might switch your EGR, if the new one doesn't plug in.

Use a P13.

Nothing could be easier, right?
 

jam05pr

Member
Ok, I finally got my jdm h22 and its already in my prelude. The car turns on and appears to be running pretty good. I left the jdm fuel rail and switched the distributors. I just had one question regarding the vtec. Since I am using my H23 harness which doesnt have the vtec wires how would i connect the vtec to the ecu(p13). If anybody can explain to me how to do this I would really appreciate it since an H22 isnt an H22 without vtec. Thanks.
 

jam05pr

Member
Thanks for your reply. This is really going to help me finish this little project. I'll let you know how it goes as soon as I find the p13 ecu. If anybody knows of someone that has an obd1 p13 manual ecu please let me know because i might be interested in buying it.
 

reckedracing

TTIWWOP
VIP
FREE WIRE DIAGRAMS ON AUTO ZONE.COM

you need to make your wires match the wires for the H22 vtec lude...
good luck

TIPPY TOWH
 

jam05pr

Member
Ok, I finally got to test drive my jdm h22a prelude. It is running like crap. i am guessing it is because I am using a p14 ecu. Could this be the reason that it is really slow or could it be something else.

I also was curious why the p13 ecu comes with dual stage vtec and what exactly is it. Thanks.
 

imprt92

Member
i also am using my h23 ecu for my h22 swap. mine is runing like crap also! does yours cut out at around 5000 rpm? mine is doing this as well. i bought a p13 it should be here any day now. ill let you know if it helps me. maybee we can give each other ideas on what we find out. ill let you know
 

imprt92

Member
by the way did you get the dist. wires figured out? if so what wires [ what color wires ] are they? and did you change your rail or just make the hose longer?
thanks
 

jam05pr

Member
I really dont know what is wrong with mine. It just seems too slow even though it doesnt have vtec. I would think it would still be pretty quick if it didnt have vtec. Does yours feel really slow compared to the h23?

For the distributor all I did was change the h22 one for the h23 since I used the h23 harness. I'm pretty sure someone can tell you how to do it with the h22 dist.

I used the jdm fuel rail and just added a longer hose.
 

tab

Super Moderator
The H22 is slower without VTEC. VTEC makes 200 HP, H22 w/o VTEC I heard makes 125 hp, about the same as a F22.

Got VTEC? On DOHC honda engines, VTEC makes a huge difference.
 

jam05pr

Member
Thanks for that info. I thought that maybe it was my motor that was messed up but i guess not since it is running smooth. Well, I guess i'm going to have to get that p13 ecu pretty quick because i hate the way the h22 feels without vtec.

If i get the p13 ecu my car should accelerate faster too right since with the p14 it feels so slow going through the rpm's.
 

tab

Super Moderator
If i get the p13 ecu my car should accelerate faster too right since with the p14 it feels so slow going through the rpm's.


P14=wrong fuel maps, no VTEC. Same story.

The VTEC engine essentially switches cam profiles at 5000 rpms(H22). On DOHC engines the profiles change on both intake and exhaust sides. On SOHC engines(like F22B1), the profile changes only on the intake side.

Sooooooo, the DOHC VTEC engines use VTEC technology to create more power. The SOHC models use VTEC more for the purpose of economy. This is why a VTEC headswap on an F22 is a big waste of money IMHO. ;)

Get the P13. :spin:
 

jam05pr

Member
hey guys and girls(if there are any), my swap has been complete already but I had one question. I am using the h23 tranny and was just wondering if this would cause a problem with the way the car performs.
 

imprt92

Member
im not sure what the difference is but i know they are geared diferently. i think the h22 is geared tighter meaning shorter.
 
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