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ODB conversion help.

05-22-2009, 12:34 PM
OK so I did a motor swap in my 97 EK hatch (ODB2A). I put in a 94 LS motor (ODB1). I hooked up the hatch's wiring harness to the engine, and I am still using the ODB2 ecu. I can start it, but when it is cold it has a real rough idle (bouncing idle between 1500 and 2000 rpm). Once it warms up the idle flat lines and balances out at about 1000 rpm.

After it warms up and i step on the gas to slowly and steadily increase the rpms it doesn't increase smoothly. between 1500 and 2000 rpms it still bounces, once it past 2000 rpm its fine. I do have a CEL on it says O2 sensor (secondary) and Idle Air Control Valve, but I have cleaned and replaced the idle air control valve part more than once and that didn't fix it.

Any ideas? Should I switch to the ODB1 ecu? (if i do this will I still be able to pass emissions?)

06-04-2009, 08:55 AM
You need the OBD1 ecu and no, you wont be able to pass emissions

06-04-2009, 12:22 PM
I'm guessing that your car originally came with a non-vtec D-series engine. The non-vtec Civics (and automatic ones) from '96-'00 had a 3-wire IACV, where the '92-'95 Civics & Integras has a 2-wire IACV. That would explain why you are throwing that code. Here's some info on what to do, if this is indeed the case:

06-17-2009, 08:10 AM
CivicSpoon ( with your advice is it possible to still run the motor with the ODB2 ecu?

06-17-2009, 02:06 PM
It will run, but you should get a '96-'98 P75 (Acura LS/RS/GS) ECU. Otherwise, you're going to be running on the fuel and ignition timing maps for a SOHC D-series engine (whatever your stock engine was). By doing that you're going to be running lean, and performance will definitely suffer.

06-25-2009, 11:30 AM
I've already had all the wiring done but just running on the wrong ECU hopefully that should solve my problem... but now where to find a cheap ECU... or cheap chipped ECU online?

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