B18b Swap + Obd2 To Obd1 Conversion

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Senior Member
I have a 97 civic DX with a 99 usdm b18b. I did a obd2 to obd1 conversion using the skunk2 harness. I had a check engine light for coolant temp sensor (my moron friend put the wrong plug on it) The car was fine when I had the cel aside from low idle when cold and high idle when warm but now that I plugged the right plug in and eliminated the cel my headlights dim when I push in the throttle unless I'm above 4000 rpm's, they also dim at idle but if I rev past 4000 they will brighten back up. I've tested my alternator and battery and both are functioning properly. I have heard some other people having similar problems when using conversion harnesses I was wondering if anyone else had this problem or if they knew how to fix it.
Your car is obd2 and you have an obd2 motor.. or wait.. that motor might be obdb (a.ka. obd3) and your car is obd2, that is why you used the harness adapter?

Anyways... check grounds, an alt can test good, but still be the problem (seen it many times).. check all electrical stuff (i.e. ignition componants, etc.)
car is obd2a and motor is obd2a I did the obd1 conversion for a few reasons, it makes the swap easier as you don't have to run a secondary O2 sensor wire and a few other wires. Also I will be turbo charging in april and in order to run hondata you have to be running obd1. I have checked all the grounds, I'll check the other stuff on sunday
Originally posted by Domeskilla@Feb 28 2003, 11:12 PM
ah.. just some fyi.. Hondata now supports obd2 :)

keep us up on what the problem is.

lol, yeah they didn't in october when I did the swap ;) also hey haven't come out with anything obd2 for the p75 from what I've seen and its still an obd1 ecu with obd2 plugs on it

Hondata has OBDI P28 ECUs modified with OBDII connectors. These plug straight into an OBDII vehicle with no adapter harness necessary. Available with OBDII A (96-97) and OBDII B (98-00) connectors.