Still sort of a noob to all of this, so I apologize. So I have a 99 Civic Si with an older B16A (gen 1) swap on it, so it's an OBD0. The other day, after my dad took my car and drove it around, he ended up fueling it up for me. Unfortunately, he didn't twist the gas cap all the way for the "three clicks". The very next day, the check engine light comes on and I told him about that gas cap thing. I tightens it and it's been almost a week now and the CEL is still there. I'm pretty sure if that was the problem, it would've automatically gone away by now (I did not bother resetting the battery or anything yet because I'd have to remove the OEM unit and get the code from the dealer). Now however, I'm thinking that it may be the vehicle speed sensor because the speedometer jumps and spikes around a lot when I'm driving. However, I've noticed this a week or two prior to this CEL incident, but now it seems to be happening a little more often.

This leads me to my next point, since I have an EM1 with an older OBD0 engine in it, would I have to read the code from the under the passenger seat and take out the carpet? Or would there still be some way to read it with an OBD2 Reader? (As you can tell, I'm not very good with cars with older motor swaps).

 

OBD0 -- There's an LED light on the ECU that blinks the codes whenever the key is in ON(II). Locate the ECU and you will be able to read the codes.

 

Ah alright, thanks a lot for your response!

 

Well, it turns out, this B16A swap didn't come with the PR3 ECU (which I was expecting for some weird reason, not even sure how I came to that conclusion). It's paired with the USDM P2T-A11 OBD2 from the EM1 (stock virgin). Looks like I'll probably just buy a reader instead and probably return it. Lmfao.

 

Was going to comment on this "99 Civic Si with an older B16A (gen 1) swap on it, so it's an OBD0"
The engine doesn't dictate what electronics are being used on it.

Seems you figured it out already on your own.

 

Yeah, first time dealing with swaps and ECU's (the more electronics side of things) so I got really confused. But now I know, so that's good I guess.