JDM H22A Swap into a 5th gen... what do I need to know? - Honda Prelude Forum

Keith · 10-07-2004, 12:45 AM

Hey guys,

Well it looks like if I don't find the problem on my motor soon, I'll be getting a new/used motor. I would like a JDM motor (higher compression), OBD1, closed deck. What do I need to know/get in order to get it to work in my 5th gen? I know that I'll need a conversion harness from the OBD2 to OBD1 ECU. But some questions I have is;

- Do I have to worry about the OBD1 distributor?
- Don't JDM ECUs have a speed governor? If so, what is the bypass for it?
- The power steering on the 4th is different from the 5th gen... can I just use my 5th PS components?
- Are the TPS and MAP sensors different from the 5th gens as I've seen on some 4th gen Preludes?

Any input or experience would be greatly appreciated.

Keith

JustXtreme · 10-07-2004, 07:09 AM

i can answer one question yes the JDM Ecu has a governor on it

Zbone · 10-07-2004, 07:29 AM

^^ can't you use a chipped P13 to overcome that?

JustXtreme · 10-07-2004, 08:22 AM

I don't know what that is but i want to know a way around it

Zbone · 10-07-2004, 09:16 AM

Quote:

Originally Posted by JustXtreme

I don't know what that is but i want to know a way around it

OBDI (conversion) W/ P13 ECU (remapped). do a search on ebay for "P13 ECU" and see what you come up with. or, do a search here on PO. I know this issue has been covered before... Basically, if you are OBDII (97-up, USDM) your tuning capabilities are limited... if you convert to OBDI (up to 96, i believe) you can have the ECU "chipped" to remove the govenor/rev limiter, rework the fuel maps, and change vtec engagement... some companies will "chip" an ecu based on your specific setup. just be careful, and go with a reputable company.

anyone else?

kotetu · 10-07-2004, 09:36 AM

I'm curious as to how fast you need to go? I mean, if the ecu is limited to 115mph, or 120mph, isn't that fast enough? how many of us actually go faster than 120?

1/4 mile runs rarely hit 120 in preludes (FI guys may be an exception), and when does autoX run up that fast? Even when I drive to Las Vegas, I rarely hit more than 100mph. It just seems to me to be a waste of time to worry about a speed governer.

In terms of programability, I have heard the p13 isn't the best. Don't most people go with a P28 and hondata or something like that?

Also, if your car is OBD2, but the engine is OBD1, what about the harness that is already running into the engine? do you need to do a custom job between the engine and the rest of the car?

JayZ98 · 10-07-2004, 01:45 PM

Quote:

Originally Posted by Keith

Hey guys,

Well it looks like if I don't find the problem on my motor soon, I'll be getting a new/used motor. I would like a JDM motor (higher compression), OBD1, closed deck. What do I need to know/get in order to get it to work in my 5th gen? I know that I'll need a conversion harness from the OBD2 to OBD1 ECU. But some questions I have is;

- Do I have to worry about the OBD1 distributor?
- Don't JDM ECUs have a speed governor? If so, what is the bypass for it?
- The power steering on the 4th is different from the 5th gen... can I just use my 5th PS components?
- Are the TPS and MAP sensors different from the 5th gens as I've seen on some 4th gen Preludes?

Any input or experience would be greatly appreciated.

Keith

Hey Keith,

I am in the same position as you are needing to drop another engine. Check out my lovely thread in NA as well!

I have done a good amont of searching and pm'ing here to people who have done this already.

So far, I have came to the following conclusions:

1 - If your not planning on switching to OBD1, then u can use the OBD2 distributor, US OBD2 ECM and engine harness, injectors, crank/balancer pulleys. (This is my route cause it will be a little cheaper initally)

If you are planning on switching ECM's, I would junk the jdm P13. I would run a P72 (94-95 GSR), conversion harness. That is what I hear is good while keeping allot of the OBD1 equipment on the engine. The maps are somewhat close to the Jap A/F maps.

2 - Connection for the crank position sensor is in a diff location. USDM H22A's the sensor is located on the block, compared to the JDM H22A where it is located in the distributor (obd1). We will need to run the cable from a OBD1 distributor to the sensor coming off the firewall if you switching ecu's.

3 - Secondary Header flange will not bolt up to us cat. So if you dont already have a aftermarket 5th gen header you will need one. Axle's will fit just fine to the Manual tranny.

4 - The transmission cabling I have heard mixed things on. Some say we can use our existing cable's without a problem. Other say u need to buy the entire change over (not just the long block) with cables that work. I guess well know for sure when we get em, though I am buying the entire engine to be safe.

I believe the ps system is the same in what it does and will work with our cars. I am not too sure about the TPS/MAP sensors.

When I get my motor in about two weeks, here is the list of things I am changing. Then some more serious and perhaps unessary down the road.

Water pump
Timing belt (balancer too if you are using)
Manual Tentioner
The usual plugs, wires, cap & rotor.
Oil & S2K Filter
Various gaskets/seals. VTEC solenoid, Cam seal, distributor & balance shaft.
New some hardware as well.

Can anyone else add some info here? Maybe not first hand, just differences that you know of. Thanks guys!

Zbone · 10-07-2004, 01:50 PM

http://cgi.ebay.com/ebaymotors/ws/eB...category=33596

Check this out, it will work for your application...

JayZ98 · 10-07-2004, 01:57 PM

^^ Looks like just a US P13 with the OBD1>2 harness already installed. That would work, I dont know about the "JUN chipped" though.

Has any one heard of them doing this? I have not. I would be a quite leary of just plugging that in my new engine. Especially, cause I dont see any mention of offical documents that can verify this. Not to mention its from ebay.

Keith · 10-07-2004, 09:18 PM

Quote:

Originally Posted by JayZ98

Hey Keith,

1 - If your not planning on switching to OBD1, then u can use the OBD2 distributor, US OBD2 ECM and engine harness, injectors, crank/balancer pulleys. (This is my route cause it will be a little cheaper initally)

If you are planning on switching ECM's, I would junk the jdm P13. I would run a P72 (94-95 GSR), conversion harness. That is what I hear is good while keeping allot of the OBD1 equipment on the engine. The maps are somewhat close to the Jap A/F maps.

I would like to go OBD1 so maybe I'll look for a P72 ECU or a USDM 4th gen ECU (P13)

Quote:

Originally Posted by JayZ98

2 - Connection for the crank position sensor is in a diff location. USDM H22A's the sensor is located on the block, compared to the JDM H22A where it is located in the distributor (obd1). We will need to run the cable from a OBD1 distributor to the sensor coming off the firewall if you switching ecu's.

Yeah, I read about that. Hopefully, that won't be difficult... I would like to see some pics of people who have done it before.

Quote:

Originally Posted by JayZ98

3 - Secondary Header flange will not bolt up to us cat. So if you dont already have a aftermarket 5th gen header you will need one. Axle's will fit just fine to the Manual tranny.

I already have a DC Sport CC header... I have a 4th gen JDM tranny with LSD.

Quote:

Originally Posted by JayZ98

4 - The transmission cabling I have heard mixed things on. Some say we can use our existing cable's without a problem. Other say u need to buy the entire change over (not just the long block) with cables that work. I guess well know for sure when we get em, though I am buying the entire engine to be safe.

I don't think this should be a problem since I already use a JDM tranny.

Quote:

Originally Posted by JayZ98

I believe the ps system is the same in what it does and will work with our cars. I am not too sure about the TPS/MAP sensors.

The PS system is a tad different from the 4th gen to 5th gen to compensate for spacing issues.

Thanks for the info... keep it coming and give any specifics if you got them.

Keith

JayZ98 · 10-09-2004, 12:05 PM

Quote:

Originally Posted by Keith

I would like to go OBD1 so maybe I'll look for a P72 ECU or a USDM 4th gen ECU (P13)

I already have a DC Sport CC header... I have a 4th gen JDM tranny with LSD.

Yeah, ideally I would like to do this as well. I think it would be $250 total (ECM & harness). Plus extra labor if a shop would be doing the pinout and wiring.

So have you already been using the M2B4 tranny? Did you need to replace or modify your US shifter cables? Or even JDM shifter assembly to make this work on your 98? You have a SH right?

I don't believe there is any modification required or that you have to order the optional cables from them. Either from hmotors or osaka; Hmotors told me I need to purchase the complete changeover.

I know people have been running this tranny for a while without any issues.

Quote:

Originally Posted by Keith

The PS system is a tad different from the 4th gen to 5th gen to compensate for spacing issues.

Thanks for the info... keep it coming and give any specifics if you got them.

Keith

Hmmm. Spacing as in wheel clearence and turn radius? I hope the differences are not that relivent that we would need to change the PS system over to the existing 5th gen.

Yeah I would love to hear more from some people who have done this personally. I think Billy in your thread mentioned that he had already done the JDM swap in a 5th gen. Or maybe it was the US model. Perhaps he could shed some light on specifics for us here? *ahem

JayZ98 · 10-10-2004, 09:24 AM

y0 y0 y0 Anyone gots the info!?

TruNinja619 · 10-10-2004, 10:01 AM

Quote:

Originally Posted by Zbone

OBDI (conversion) W/ P13 ECU (remapped). do a search on ebay for "P13 ECU" and see what you come up with. or, do a search here on PO. I know this issue has been covered before... Basically, if you are OBDII (97-up, USDM) your tuning capabilities are limited... if you convert to OBDI (up to 96, i believe) you can have the ECU "chipped" to remove the govenor/rev limiter, rework the fuel maps, and change vtec engagement... some companies will "chip" an ecu based on your specific setup. just be careful, and go with a reputable company.

anyone else?

its up to 95.....

96 (even though its a 4th gen) has an OBDII ECU

is it ok if you use a USDM OBDI P13 on a 5th gen..... b/c he's basically using a 4th gen motor....

Keith · 10-10-2004, 12:34 PM

Quote:

Originally Posted by JayZ98

Yeah, ideally I would like to do this as well. I think it would be $250 total (ECM & harness). Plus extra labor if a shop would be doing the pinout and wiring.

Hmmm... prices I'm looking at are about 200$ for the USDM P13 ECU + 100$ for the harness... That's about the going price anyhow.

Quote:

Originally Posted by JayZ98

So have you already been using the M2B4 tranny? Did you need to replace or modify your US shifter cables? Or even JDM shifter assembly to make this work on your 98? You have a SH right?

Nope, not at all... tranny just bolts right on

. I have a Base Lude...

Quote:

Originally Posted by JayZ98

Hmmm. Spacing as in wheel clearence and turn radius? I hope the differences are not that relivent that we would need to change the PS system over to the existing 5th gen.

No, the power steering + reservoir set up in the engine bay differs from the 4th gen and 5th gen... I guess that's not JDM specific tho...

Quote:

Originally Posted by JayZ98

Yeah I would love to hear more from some people who have done this personally. I think Billy in your thread mentioned that he had already done the JDM swap in a 5th gen. Or maybe it was the US model. Perhaps he could shed some light on specifics for us here? *ahem

Yeah, I think Billy was referring to doing engine swaps in general, not JDM 4th gen to 5th gen specific. But I think I'm going with it this week... I'll definitely post my experiences with this swap.

Keith

JayZ98 · 10-11-2004, 07:52 PM

Cool. I am leaning toward the JDM p13 then have it chipped to run with hondata or something. Glad to hear the cables and shifter assembly is the same and that it is only engine bay space on the PS system that may be a concern.

How do you plan on going with for the long block assembly? I am looking to get a little more competitive price from steve @ hmotors for a complete engine and M4B2 tranny.

Good luck with everything Keith! Please take notes and pix if you can and keep me updated here!

I would appreicate it as I might even drop this in myself with a good friend in probably three weeks. I just would need a few things.

ScottH23 · 05-11-2005, 01:53 PM

Hi guys im using my friends account here, but i just want to bring this thread back to life and ask a few questions.

As of now we have a 5th Gen Lude with a JDM OBDI motor in it. Everything is connected but as we try to start the motor, it would crank and wont start. We check the fuel pressure and its 45 on the fuel rail. Then we check for the spark on the spark plug wires but nothing is coming out. Can anyone help us out on trouble shooting.

So far the only code that is throwing out is Code 1. We are still using the wire harness from the OBDII. Is that a problem? We're still using the OBDII distributor. The ECU that we're using is the JSpec P13 and we are using a harness converter with this. Could any of these cause our car to not have any spark?

If you guys need more information to help troubleshoot plz tell me....
Thanks
Dzuy

Keith · 05-11-2005, 04:14 PM

First, you should sign up for your own account... using another person's account is frown upon here...

Secondly, did you swap oil pump housings so you can use the OBD2 CKP + TDC sensors?

Keith