Fuster_Cluck

I'm getting ready to purchase my first motor and also do my first swap. I am excited as hell about starting this but at the same having some questions as I read different posts.....

I was reading up on OBD's and would like to see if I am on the right track.
This is copy / paste as I read it.

There are 4 well maybe 5 flavors of OBD that you should be concerned with. OBD stands for On Board Diagnotics. Basically the invention of electronic Fuel Injection was a good idea. Further followed by electronic engine control.

I am not familiar with anything older than 1988 and I dont know much about anything newer than 2000.

1988 - 1991 you have OBD 0 or pre OBD. This is found in all the older CRX's civic's, integra's, you name it between those years.

1992-1995 was OBD I. Basically it had everything OBD 0 had and then some. This helped to further fine tune the engine controls.

1996-1998 was OBD II. This was everything OBD I had and more. just change, emissions laws are getting stricter, trying to put out less polution, and making the engine more efficient.

1999-2000 was OBD II.5. Everything OBD II had and more but kind of a standard between all vehicle makers. check out http://www.obdii.com/ for more info.

2001 + is OBD III (so I've heard, havent played with any yet). however the 2001 integra is still OBD II and they never really went OBD II.5 like the civics did.


Its like this, OBD 0 ECU plugs differ from OBD I. OBD I plugs differ from OBD II. And so on. OBD I has more sensors/controls than OBD 0. OBD II has more sensors/controls than OBD I. You cant take an OBD II ECU and plug it right into your OBD I car. its like plugging a square peg into a round hole. it dont fit

Since I am most familiar with OBD I and II let me give you an example. OBD I cars came equipped with only 1 O2 sensor before the cat. OBD II had 1 before the cat and 1 AFTER the cat to make sure the cat was still working. OBD II also integrated a Crank Fluctuation sensor on the oil pump. And a fuel tank pressure sensor. OBD I uses 2 wires for the fuel pump relay and OBD II uses 1. OBD II B16A2's (99-00) use different injector harness plugs than OBD I cars. Same with IAC. IAC is also wired differently on OBD II than OBD I. The distributor's also vary between years.

What does this mean to you as an avid swapper?
Well here's the cool stuff. You cannot and I repeat cannot just swap out the under dash wire harness's. for 1 its a couple hundred dollars for the harness and 2 it wont fit. wires have different plugs, different components, and wired differently.

What you would NEED to do to make an OBD II motor work in an OBD I car... is to first, gather all the extra **** that OBD II has that OBD I doesnt. PTANK sensor, 2nd O2 sensor, etc. This is kind of a lost cause and way too much effort for what you are trying to accomplish. I'd rank you up there with the guy who swapped an NSX motor into a CRX, because he "could" and nobody "had".

Its totally pointless, your car will be down for a while longer, will cost more, and be more of a hassle.

Now, as an alternative, you could swap a newer motor into the car and run an older ECU. But you would also need an older motor harness or adapt your existing harness to work. Just leave the extra sensors/controls unplugged, because the older ECU doesnt know what to do with them anyways. That is the route I would take if your hell bent on a 99-00 motor.

What would I do? I would order a B16A3 (USDM Del Sol Si VTEC motor) or a JDM SiR2 motor (B16A OBD-I)

In Japan there is no such thing as a B16A2. they are all just B16A. thats it. To make your life easy, get yourself a good OBD I motor. Plain and simple its going to cost you less and be a hell of a lot easier to swap in.

1 more topic before I close. It is far easier to go from a newer OBD to an older version. Basically it is easy to take a 99-00 civic Si and run an OBD I ECU in it. you just need a jumper harness or build your own, and the ECU. Hondata doesnt make an OBD II unit

You always want to run whatever OBD your car currently is. Unless you want to go back a generation. However I would suggest you steer clear of the OBD 0 setup as that is as much of a pain as going to OBD II. It is easy to go from OBD II to OBD I and thats the only conversion I'd do\have done. Period.


If I am understanding this right, I need to get a GSR motor that is OBD I -> 92-95 since I have a 93 Cx which is OBD I. I am most likely going to order my motor from hmotorsonline since they have great prices and great feedback from many. The site says the motors are from 94-01. So it's a 2 out of 8 chance that I get a OBD I and better odds that I get a OBD II or higher.

So, this is what's needed to get an OBD II motor into my OBD I Cx: "What you would NEED to do to make an OBD II motor work in an OBD I car... is to first, gather all the extra **** that OBD II has that OBD I doesnt. PTANK sensor, 2nd O2 sensor, etc."

Would I get all this **** with my motor or is this something I have to get on my own? Sorry, for all these questions but this is the first thing I've EVER read that explains the OBD's!

function83

if you swap in a 94-95 obd1 gsr motor. just plug in the harness and ecu.
everything bolts right in basically plug and play.

now if you get 96-and up ob2 motor just plug in the obd2 harness at the shock towers, there will be a few plugs that won't be needed to plug in. then get a obd1 ecu either a p72, p30 or a chipped p28 with a b series program.

basically everything is plug and play. just make sure you use an obd1 ecu.
its really easy.

btw you will need to run 3 wires for vtec: vtec ground, vtec oil pressure switch, and vtec solenoid. also one wire for the knock sensor.

heres a link to help you out.
http://tech.hybridgarage.com/tech/5gtech/index.html


[Modified by djhatch, 8:18 AM 12/30/2002]

VTECVillain

You can use any GSR swap from 94-01. The OBDII motors will bolt in and all you would need is an OBDI P72 ECU to run everything. You can get a much lower mileage OBDII setup than a 94-95 OBDI. I have a 99 B18C1 in my 92 VX, which I bought with only 14K on it.

I wouldn't recommend the P30 or P28 ECU's unless he plans to use a single runner intake manifold.