I have a few questions and yes I searched and searched.

1. I'm hearing a lot of people saying use the jdm p73, do NOT use the p73 usdm one, why though ?

2. Since the ecu ( p73 ) is obd2 and the body harness is obd1, will it plug right up to the p73 ? If not what conversion harness do I need, and obd2 to obd1 or odb1 to obd2 ?

3. Since it was an auto, all I need to know is can I still use all these mounts in the pic ? Or do I need a special one from hasport ? I am hearing way to many conflicting stories on this.



4. To retain power steering and a/c, is there anything special I need to do ?

If anyone can think of anything else to look out for or buy ahead of time please mention it.


Modified by 90blackcrx at 8:32 PM 1/29/2005


Modified by 90blackcrx at 1:25 AM 1/30/2005

 

1.USDM doesn't have the speed limiter.that's the only real advantage i can think of.
2.your body harness will not plug right into the OBDII ECU.you can get a conversion harness(OBD2[a or b] ECU to OBD1 chassis.you'll have to add the necessary additional wires on the chassis harness for the extra OBDII sensors.if you use the ITR engine harness instead of your civic engine harness,it will plug right in to your civic chassis harness and have all the wires needed.if you use your Civic engine harness,you'll have to change some plugs(injectors,distributor,alternator),extend some wires,and add the OBDII sensor wires.my recommendation is an OBDI ECU.i believe(somebody please correct me if i'm wrong)you'll have to get the immobilizer removed/disabled before you can even use the ITR ECU.
3.you'll need an auto to manual upper passenger side mount.the others are as shown in that diagram.
4.for P/S and A/C,use the Integra pumps.they will hook right up to your civic lines.
Chris

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TeamNextGenChris &raquo;</TD></TR><TR><TD CLASS="quote">1.USDM doesn't have the speed limiter.that's the only real advantage i can think of.
2.your body harness will not plug right into the OBDII ECU.you can get a conversion harness(OBD2[a or b] ECU to OBD1 chassis.you'll have to add the necessary additional wires on the chassis harness for the extra OBDII sensors.if you use the ITR engine harness instead of your civic engine harness,it will plug right in to your civic chassis harness and have all the wires needed.if you use your Civic engine harness,you'll have to change some plugs(injectors,distributor,alternator),extend some wires,and add the OBDII sensor wires.my recommendation is an OBDI ECU.i believe(somebody please correct me if i'm wrong)you'll have to get the immobilizer removed/disabled before you can even use the ITR ECU.
3.you'll need an auto to manual upper passenger side mount.the others are as shown in that diagram.
4.for P/S and A/C,use the Integra pumps.they will hook right up to your civic lines.
Chris</TD></TR></TABLE>

You are right on everything except the immobilizer this only exsits on the k20 usdm ecu. You will need to get a skunk 2 obd2-obd1 conversion harness from skunk2racing.com.

 

Ok, I would really like to hear why the usdm p73 is so bad to use, I have heard some other people tell me it is, and hopefully they will chime in.

So I do need a special top trans mount then ?

And when ordering the conversion kits, its like this right

First number would be the ecu side, second number would be the plugs going to the chassis correct ? Confused, here is an example.

obd2 to obd1
obd2 plugs into the ecu and the obd1 would hook up to the chassis right

Just trying to understand it better.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 90blackcrx &raquo;</TD></TR><TR><TD CLASS="quote">Ok, I would really like to hear why the usdm p73 is so bad to use, I have heard some other people tell me it is, and hopefully they will chime in.

So I do need a special top trans mount then ?

And when ordering the conversion kits, its like this right

First number would be the ecu side, second number would be the plugs going to the chassis correct ? Confused, here is an example.

obd2 to obd1
obd2 plugs into the ecu and the obd1 would hook up to the chassis right

Just trying to understand it better.</TD></TR></TABLE>

Anyone else

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 90blackcrx &raquo;</TD></TR><TR><TD CLASS="quote">So I do need a special top trans mount then ?

And when ordering the conversion kits, its like this right

First number would be the ecu side, second number would be the plugs going to the chassis correct ? Confused, here is an example.

obd2 to obd1
obd2 plugs into the ecu and the obd1 would hook up to the chassis right

Just trying to understand it better.</TD></TR></TABLE>
yes,you do need a special upper tranny mount.i've used this mount on three different conversions,and was very happy.little cheaper than HAsport,if that's a concern.if not,of course HAsport's stuff is top notch.

http://www.jdmshit.com/hcp/index.html

your way of ordering the conversion kit sounds right,but i'd specify exactly what you want anyway-the majority of people buying harnesses are getting OBD2-OBD1.you don't want your supplier thinking that's what you want too and sending you the wrong thing.
chris

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TeamNextGenChris &raquo;</TD></TR><TR><TD CLASS="quote">you want anyway-the majority of people buying harnesses are getting OBD2-OBD1.you don't want your supplier thinking that's what you want too and sending you the wrong thing.
chris</TD></TR></TABLE>

But if I'm using an od2 ecu in an obd1 chassis, wouldn't I be ordering the obd2 to odb1 ?

See I just want to know what side the first number means when people say obd2 to obd1 , does it mean ecu to chassic or chassis to ecu ?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 90blackcrx &raquo;</TD></TR><TR><TD CLASS="quote">

But if I'm using an od2 ecu in an obd1 chassis, wouldn't I be ordering the obd2 to odb1 ?

See I just want to know what side the first number means when people say obd2 to obd1 , does it mean ecu to chassic or chassis to ecu ?</TD></TR></TABLE>
haha,now you've got me confused!just any site i've seen that sells jumpers has a description so you'll know exactly what it's for.for instance,Katman's site tells what ECU and chassis each harness is for:
http://ecu.ff-squad.com/jumper.obd1.htm
like i said,just order it according to how your supplier has it named,and it definitely won't hurt to specify your setup so they can make sure you get the right part.
chris

 

In 1992 all hondas were equipped with an on board diagnostics system or OBD1 system in 1996 they changed to OBD2, and so on.
so:
92-95 = OBD1
96-98 = OBD2a
99-00 = OBD2b

All ecus manufactured in 92-95 are OBD1 and all cars are OBD1. All cars manufactured in 96-98 are OBD2. There for if you want to put an obd2 ecu in you obd1 car, encyclopedia brown would figure that your obd1 car is a 92-95 car and your ecu is a 96-98.

I would much rather have the same ecu designated for the generation of car, the OBD1 would be the best, because if you convert to obd2 you will have to run a **** load of wires for a bunch of sensors and that will be a big *** headache. I don't know you fiqure it out.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TeamNextGenChris &raquo;</TD></TR><TR><TD CLASS="quote">
haha,now you've got me confused!just any site i've seen that sells jumpers has a description so you'll know exactly what it's for.for instance,Katman's site tells what ECU and chassis each harness is for:
http://ecu.ff-squad.com/jumper.obd1.htm
like i said,just order it according to how your supplier has it named,and it definitely won't hurt to specify your setup so they can make sure you get the right part.
chris</TD></TR></TABLE>

Thanks, but I know some sites really don't get into a description of it.

So anyways what makes the jdm p73 closer to an obd1 ecu ?

And after reading that site, it seems like different sites go by it differently.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by saywhat &raquo;</TD></TR><TR><TD CLASS="quote">In 1992 all hondas were equipped with an on board diagnostics system or OBD1 system in 1996 they changed to OBD2, and so on.
so:
92-95 = OBD1
96-98 = OBD2a
99-00 = OBD2b

All ecus manufactured in 92-95 are OBD1 and all cars are OBD1. All cars manufactured in 96-98 are OBD2. There for if you want to put an obd2 ecu in you obd1 car, encyclopedia brown would figure that your obd1 car is a 92-95 car and your ecu is a 96-98.

I would much rather have the same ecu designated for the generation of car, the OBD1 would be the best, because if you convert to obd2 you will have to run a **** load of wires for a bunch of sensors and that will be a big *** headache. I don't know you figure it out.</TD></TR></TABLE>
i think he understands what years the different designations are for,he's just having trouble figuring out which harness to get.
if he has the Integra engine harness,converting to OBDII won't be too hard.his car is an EX,so all the VTEC stuff is there.the OBD2 Teg engine harness plugs into his chassis harness.he just has to get the right jumper harness,and add the knock sensor wire and wires for the couple extra OBD2 sensors from the ECU plugs to the shock tower plugs.no big deal.
however,i'm with you-i think an OBD1 ECU is still the way to go since it will only require one added wire(knock)and gives you more flexibility as far as ECU programs.
Chris

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 90blackcrx &raquo;</TD></TR><TR><TD CLASS="quote">

Thanks, but I know some sites really don't get into a description of it.

So anyways what makes the jdm p73 closer to an obd1 ecu ?

And after reading that site, it seems like different sites go by it differently.</TD></TR></TABLE>
like i said-order by the description given by whoever you decide to buy it from,and listing your setup should ensure the proper part gets to you.if you find a site that doesn't have a good description,or somebody that can help you,why not go somewhere else?no need to be uncertain when there are tons of people that sell jumpers.if you want,i can recommend a few good sites i've bought from.

So anyways what makes the jdm p73 closer to an obd1 ecu ? i'm not really sure what you mean by that?
Chris

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TeamNextGenChris &raquo;</TD></TR><TR><TD CLASS="quote">
i think he understands what years the different designations are for,he's just having trouble figuring out which harness to get.
if he has the Integra engine harness,converting to OBDII won't be too hard.his car is an EX,so all the VTEC stuff is there.the OBD2 Teg engine harness plugs into his chassis harness.he just has to get the right jumper harness,and add the knock sensor wire and wires for the couple extra OBD2 sensors from the ECU plugs to the shock tower plugs.no big deal.
however,i'm with you-i think an OBD1 ECU is still the way to go since it will only require one added wire(knock)and gives you more flexibility as far as ECU programs.
Chris</TD></TR></TABLE>

Your reading my mind, yes I know the difference and when the odb1 and obd2 ecu start.

But Chris you said the jdm p73 was more like an obd1 ecu ( even though its obd2 ) , just wondering why the jdm p73 is more like a obd1 but the usdm one isn't ? Does the jdm one not look for as many sensors ?

And I know the p28 would be the better choice, I'm gonna talk to the customer and ask him what he wants, at the end its all up to him.

And I still want to find out for sure if
obd1 to obd2 means
odb1 ecu to obd2 chassis , I really don't know any other way to explain it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 90blackcrx &raquo;</TD></TR><TR><TD CLASS="quote">And I still want to find out for sure if
obd1 to obd2 means
odb1 ecu to obd2 chassis , I really don't know any other way to explain it.</TD></TR></TABLE>

From my experience it usually means chassis to ecu. But with how popular the other conversion harness is, I would make it very clear to whomever you are ordering from, which you are already aware of. GL

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 90blackcrx &raquo;</TD></TR><TR><TD CLASS="quote">

Your reading my mind, yes I know the difference and when the odb1 and obd2 ecu start.

But Chris you said the jdm p73 was more like an obd1 ecu ( even though its obd2 ) , just wondering why the jdm p73 is more like a obd1 but the usdm one isn't ? Does the jdm one not look for as many sensors ?

And I know the p28 would be the better choice, I'm gonna talk to the customer and ask him what he wants, at the end its all up to him.

And I still want to find out for sure if
obd1 to obd2 means
odb1 ecu to obd2 chassis , I really don't know any other way to explain it.</TD></TR></TABLE>
i didn't mean to imply that the JDM P73 was more like an OBD1 ECU,if that's how you took it.the main difference is just that the US P73 doesn't have the speed governor that the JDM ECU does.this can be an advantage if you plan for the car to ever see very high speeds.
as far as how the harnesses are listed,you may find some people list them differently.best thing i can say is make sure the description specifies exactly what it fits("this harness adapts OBDx chassis to an OBDx ECU"),and include your specific setup with your order.as said above,the most popular harness is the OBD2 chassis to OBD1 ECU-you don't want the seller to think that's what you want by mistake.if you buy from a reputable dealer,and specify your setup,you should haev no problems.
chris

 

Here's the bottom line from my point of view based on the fact that I first ran the JDM P73 ECU with a Kenji jumper harness only to replace it with a rechipped P28 ECU from Kenji:

RUN THE RECHIPPED P28 ECU!

"But why?"

1. The JDM P73 ECU requires the use of a jumper harness. The harness range from $150.00-$250 in price. That's a chunk of change to be spending when you're trying to get a swap running, and considering the rechip only costs $90.00 the choice is obvious based on this fact alone.

2. The JDM P73 has a speed limiter.

3. The JDM P73 doesn't make as much power as a rechipped p28 designed to optimize power output.

I ran the JDM P73 with a borrowed jumper harness while waiting for my P28, and the difference is definately noticable.

4. The P28 will have one less wire top wire up than the P73 - the knock sensor wire. The P28 doesn't look for one, while the P73 does.

BTW:

The JDM P73 is only OBD2 in PLUG-TYPE, NOT IN PROGRAM, meaning that while it plugs in like a 96-98 ECU, it doesn't look for the OBD2 extras such as the crank fluctuation sensor, secondary o2 sensor, evap system, etc.

 

^^I agree 100%.
It will make it plug and play in that ex civic.

Drop it in using the integra engine harness and plug in the p28.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TeamNextGenChris &raquo;</TD></TR><TR><TD CLASS="quote">
yes,you do need a special upper tranny mount.i've used this mount on three different conversions,and was very happy.little cheaper than HAsport,if that's a concern.if not,of course HAsport's stuff is top notch.

http://www.jdmshit.com/hcp/index.html

</TD></TR></TABLE>

I have that mount, makes it a breeze. and much cheaper than anywhere else.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 90blackcrx &raquo;</TD></TR><TR><TD CLASS="quote">

Your reading my mind, yes I know the difference and when the odb1 and obd2 ecu start.

But Chris you said the jdm p73 was more like an obd1 ecu ( even though its obd2 ) , just wondering why the jdm p73 is more like a obd1 but the usdm one isn't ? Does the jdm one not look for as many sensors ?

And I know the p28 would be the better choice, I'm gonna talk to the customer and ask him what he wants, at the end its all up to him.

And I still want to find out for sure if
obd1 to obd2 means
odb1 ecu to obd2 chassis , I really don't know any other way to explain it.</TD></TR></TABLE>

obd2-obd1 means obd2 ecu- obd1 chassis

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by one8toh8 &raquo;</TD></TR><TR><TD CLASS="quote">

obd2-obd1 means obd2 ecu- obd1 chassis</TD></TR></TABLE>

Thats weird because I just talked to an owner of a site that sells the harness and he says its the other way around.

And thanks for all the help guys.

 

Will the p30 work ?

 

P30 adds knock sensor to the mix. This means you will need to wire in a knock sensor to the ECU. The main problem with this is the need for shielded wire. If you don't use shielded wire, grounded to the correct spots, your ECU will detect phantom knock. This will cause it to retard your ignition timing & your car will lose power. It doesn't reset your timing until your next fuel up (I think).

Only use the P30/Knock Sensor if you've got wiring diagrams & your planing on doing it right (it can save your motor).

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 90blackcrx &raquo;</TD></TR><TR><TD CLASS="quote">

Thats weird because I just talked to an owner of a site that sells the harness and he says its the other way around.

And thanks for all the help guys.</TD></TR></TABLE>

Thats the thing there is two different sub harnesses 1 for an obd2 car which would be obd 1ecu to obd 2car

the one that you need is for an obd1 car to an obd 2ecu make sure you specifie this to the shop just give skunk2 a call.

 

Well Steve ( from hmotors ) does not sell usdm b18c5 anymore so I need to know if there is anything else to look out for when using a b18c5 jdm engine.

 

The jdm engine will come with a rhd engine harness. All the shock tower plugs will be on the opposite side.

So you will need to reuse the civic stock harness, and cut the obd2 injector, distributor, and alternator plugs off of the jdm engine,
or
Get a usdm obd2 integra gsr or type R engine wiring harness.

You can actually use the jdm harness if you need to. All the plugs are on the wrong side, but you can get them to reach. Alot of people choose not to do this, though.
I have personally done it on 2 different occasions and havent had any problems.

Also, if you are going to run the JDM motor with usdm ecu, be aware that the jdm itr vtec solenoid does not have the oil pressure sensor on it, like the usdm engine does.

So you can either, get a usdm vtec solenoid assembly or
you can bypass the vtec oil pressure switch, by tapping a wire from D6 (at the ecu) into the wire coming from A4.