I have previously got a gsr in an eg to pass ref but the motor and car were both obd1.
What are the laws/rules about putting a obd2 motor into a obd1 car. Is their a wrong and right way to do it?

I know some people change the motor over to obd1, but i am not sure if that is legal?

 

it's not legal...sometimes you can get away with it if you swap the complete obd2 harness to an obd1 harness. in california you have to install a motor that's the same year or newer than the one you have installed already....stupid law if you ask me....but that's california...or you can talk to a friend in another state (or humbolt county, northern ca) and get a p.o. box there and register the car in that district where they don't have smog requirements...i have a couple buddies who have done that and are able to get away with it....

 

so the only way to do it is by keeping the motor obd2?

 

no you dont have to go obd2.. the year of your car is before 1996 therefore its obd1.. and its recommended that you stay obd1. as long as the motor you have is either the same year as your car or newer and your running a usdm ecu without any check engine lights and any modifications to the motor like headers, exhaust, intake etc..

 

just to make sure i understand.

So I can legally convert the motor to obd1 as long as my car is obd1?

 

yes! it should be obd1 since your car is obd1.. just make sure you have an american ecu and get rid of all of those check engine lights.. you can also get a japanese motor smogged but your gonna have to swap over the evap purge solenoid over to the jdm engine along with getting an american ecu.

 

alright thanks for the help. One more question.

If you convert a obd2 motor to obd1 how do you use the stock ecu such as an itr? Since thier isnt an obd1 itr ecu. Is that what those conversion harnesses are for?

 

any more help would be great.

 

My friend actually ran into this problem with his crx. CRX obviously OBD0, my friend swapped a OBD1 b16 into his crx and used the conversion harness obd0 to obd1. He took it to the ref and failed so he contacted the head guy that runs all the BAR stations and explained to him what the conversion harness did. So a few months later the conversion harness was allowed to be used in barring his car. So I believe the conversion harnesses are allowed if you plan on keeping it OBD2.

 

good to know.

Basically i just want to do it the easiest way that is legal. From what i understand i will have to keep it obd2 since i have to use the ecu for that motor and there is no obd1 itr ecu.

 

correct

 

Alright. so now my next question is going to be how do i do this.

Am i going to have to wire the motor and interior engine harness obd2 (the plugs to the ecu)? Pretty much replace the ecu wiring harness with an obd 2 harness? Or is their another way?

I found this-
http://rywire.com/store/obd1-obd2b-c...ness-p-47.html
I believe it will allow me to utilize all the stock wiring with an obd2 ecu. correct?

 

92-95 civic = obd1 No cat
96-98 civic = obd2a Need catalytic converter
99-00 civic = obd2b Need cat

Motor has to be the same year as your car or newer!
USDM Ecu must be used
No check engine lights, no modifications unless its carb legal ex. Header, air intake with carb sticker

If running an obd2a/b motor in a 92-95 civic for example: b18c5 ITR then you must use the ITR p73 ecu which is obd2b with a obd2a/b engine harness. So you need to find a 96-01 INTEGRA harness that already has the modifications done to it like vtec, oil pressure switch, CFK sensor etc..

The reason why you need to find a 96 or newer engine harness is because in 96 is when obd2a was used to combat air polution therefore the distributor wires are different, the injector plugs are 2, and you use a catalytic converter.

 

correct but how are you going to wire the obd1 engine harness to the obd2b distributor? same goes for the fuel injector plugs. obd2a/b uses 2 wires whereas obd1 uses 1. Same goes for the alternator plugs the obd1 alternator plugs are different then the obd2a/b plugs. Even though you can modify the harness I dont know if you can pass a visual inspection like that.

 

You need a cat for that too.

OBD1 D/B-series CYP/CKP/TDC sensors, or an OBD1 B16A/B18C1 distributor

No, they're both 2 wire, even the wire colors are the same, you can cut and splice the plugs, or use OBD1 B18 injectors

OBD1 D-series voltage regulator in B-series case, or just use an OBD1 B-series alternator

None of the things you mentioned are emissions related, plugs for certain components changed, thats all. My point is that you can fairly easily deal with the wiring aspect of this swap and not hack everything to pieces, that said a USDM GS-R/ITR harness will make this easier and probably make more sense both finacially and in terms of time.

 

Yes I know you can swap to obd1 parts like distributor, alternator, and injectors but hes talking about wireharness and not parts.. therefore labeled what he should do to his engine harness if he was to go that route. I also mentioned that he should use a 96-01 integra engine harness already. Most people dont want to go find parts such as obd1 injectors, dizzy, alternator when they bought the complete motor that had those parts already. Besides if he decides to get a usdm b18c5 then it should come with the engine harness already therefore he just needs a conversion harness for the ecu.

BTW: "Vehicles receiving an engine that is of a newer OBD type must upgrade to the OBD level of the new engine. This includes the computer and all of the electrical components. Although the backdating of electronics and downward OBD conversions are mentioned.. they are illegal in serveral states." Aaron Bonk -Honda engine swaps

Therefore you CANNOT use a obd1 distributor, alternator, or injectors.

 

To clear some things up. I am asking the question because i bought an eg from washington that has a usdm itr motor swap and i am trying to gather info before i go to pick it up this weekend. So i will know what to expect when i get it ready for ref. I am familiar with refing an ob1 motor, but this is different.

The original owner used an obd1 engine harness in the swap. the ecu is a tuned jdm b16 ( i know i will need a usdm p73). the distributor is the oem itr (therefore obd2). not sure about the fuel injectors or alternator. i can ask him. Also I have an oem obd2 cat for it.

I am getting a little more confused as this thread goes on. I am trying to piece together all the info. This is what i have gathered so far:
If i just use an obd2 b series engine harness with the oem dizy, alternator, and fuel injectors i will just need the conversion harness for the p73 ecu (as seen in previous post)?

I really appreciate all the help. Sorry if i am asking a lot of questions, I just want to get this all clear so i can get to it wen i get the car.

Thanks!

 

BINGO!! you got it buddy.. but I dont know if they make conversion harnesses from obd1==>obd2b though.. usually people want to backdate their ecus instead so it would be obd2b===>obd1.. I could be wrong though

 

alright!

I believe i found one. http://rywire.com/store/obd1-obd2b-c...ness-p-47.html

i posted it before, their it is again.

 

so can i put a engine together... lets say a originally a obd1 block but with a obd2b cylinderhead in a obd2 car.. would they pass it?

 

i also have the same swap in my eg hatch except i have a vx model with a 98 gsr in it (still gonna reff it)...everything is obd2 except for the alternator becasue the obd2 one wasn't good...so i cut and splice an obd1 alternator plug to my obd2 harness...rywire.com does make the obd2a/b to obd1 conversion harness...in ur case and mine the rywire conversion harness does have 4 loose wire for the secondary o2 that your will have to slice in yourself...

 

From what i know i dont believe so but i am not 100% sure.

 

Now thats an interesting question. IF you used something like an OBD1 JDM B16A block (which looks exactly like JDM OBD2 B16A) with an OBD2 head on it you might pass considering the date code is stamped in the head and not the block. If you use something like say a USDM B16A3 block with an OBD2 head I doubt it based on the fact that B16A3 only exists in an OBD1 form.

 

i have an 92 honda cx but a b18c what will i need. i have read all post and got some information but my situation is a lil bit different a reply will be greatly appreciated. please

 

OP, If you are trying to Bar a Type-r motor, Find a 97 P73 ecu... The 98,00,01, have a "Fuel Tank Preasure Sensor" which will trigger your CEL.