Well hey there! Been a member since 06, but when my boosted EG got stolen kinda fell out of the scene. I'm back at it now! So...I have a 91 EF SI that I just finished swapping an OBD0 B16 into. Everything works great...almost. After driving for a minute the CEL comes up with code 21. I've checked the VTEC solenoid and oil pressure switch with OHMS reader, both came back good. VTEC engages, but it almost seems like the car bogs when it does. Not expecting a huge jump in power, but the car almost slows down when VTEC engages.

I know that you are supposed to wire up the the solenoid to pin A8 (ECU Pinouts, VTEC wiring, & ECU VTEC Conversion Information - HondaCivicForum.com), but here's where it gets tricky...my 91 SI already had A8 filled with a yellow wire that has a red dot on it, A17 was empty as it shows it should be, but not A8. Nowhere can I find a picture that A8 is already occupied, or any info leading to what that wire would have been. Everything points to that space being empty. Car starts, drives, idles, shifts etc...but has this vtec prob. So, I spliced my solenoid wire into it. Could that be the problem????? I'm still trying to find out why the hell that space wasn't already empty. Anywho, anyone with some good info on the matter would be greatly appreciated.

Thanks again for all help

INFO ON CAR- stock d16 exhaust, stock motor, stock intake, new cap/rotor, new plugs, timing is on.

 

What color is the wire above that one in your connector? Can you post a pic?

 

Sure thing! The yellow wire with the red dot is in slot A8, and that's the one I spliced in to. I just cant find another wiring guide that shows this slot occupied.

 

Bump. Anybody have anything on this???

 

have you tried tracking down where that yellow wire goes to? - shouldn't be a wire there - I would remove that wire and run the wire for the VTEC solenoid as if the pin was always empty - some cars with automatic transmission had a yellow wire at that location - maybe someone swapped an EX automatic harness into it???

 

Yeah I have tried tracing it down...it doesn't even go into my engine bay, but wraps in to my dash somewhere near my fuses. So I didn't remove that wire, but I did splice into it for my VTEC solenoid. But I have cel code 21 for some reason. I have tested the solenoid, pressure switch, and also checked all the wires that lead to it...everything checks out in the clear, but I still have that code. Also the car is running a little rough at what seems like only low RPMS. New spark plugs, cap/rotor, timing is right on, no cel light for o2 sensors or anything else minus the VTEC solenoid. Any help/Ideas??

 

Just throwing this out there...but could I be getting the codes mixed up? Could I be getting code 12 instead of 21? I keep getting mixed code lists for obd0...some have code 12 (EGR valve sensor) and other don't.

 

if you have a PR3 or PW0 ECU, you wouldn't get a code 12 - code 12 only occurs when using ECU for engines with EGR, i.e. CRX HF, DPFI cars with auto transmission in Calif., etc. - try removing the original yellow wire and plugging VTEC wire directly to ECU - can't hurt to try