Hi everyone,

I recently purchased a '94 civic CX hatchback (5 speed manual) with 180k miles on the D15 block but with a new (2k miles) mini me D16Y8 head with chipped and tuned P28. The previous owner did the swap, not me. After driving it home, I started to notice problems with the wiring. The first and most obvious issue is that all the lights on the vehicle (headlights, taillights, dash lights, etc) all pulsate while driving and idling. This seems to happen in coordination with an engine surge when idling. The RPMs will fluctuate between 900 and 1500 or so, and as the engine surges, the lights get brighter. Also, when looking under the hood, I noticed that a couple wires were cut and not connected to anything (see photo). I took the car on a road trip (150 miles) and it gave me no trouble other than the slight surge and pulsating lights, as expected. However, when I started the car on the last day, it ran very poorly. The fuel injection seemed to not be constant, as the car was silent when I wasn't pressing the gas, and when I was, it had intermittent periods when it was silent as well. It sounded like rod knock almost. It started loosing power and a bunch of white smoke came out of the tailpipe, so I had it towed to a shop. They said it was running really rich because my new spark plugs were black (also my fuel economy was steadily decreasing), but ultimately they couldn't get it to act up again. I drove it home and it's been fine ever since. After doing some research on how to fix this, I cleaned the throttle body, I replaced all the spark plugs, I tested fuel pressure, I replaced my O2 sensor as the previous one was black (the one connected to the exhaust manifold, there's no cat in my car), and I tested my battery and alternator (voltage did fluctuate around 14-17 volts along with the pulse, however), and none of these were the issue. Does anyone have any advice or a place to start looking to fix this problem or what those wires do? Anything helps, total noob here I've been told to replace the voltage regulator and the fuel pressure regulator, but I'm guessing it's more electrical because of how the surge seems related to the pulsating lights. Thanks so much!

 

The wires in your photo appear to be to the vtec solenoid on the back of the head. They are supposed to be run to the ECU.

With the voltage bouncing around like that I wonder if your ECU is Canadian while the car is USA. This would pose an interesting situation where you have an ELD in the fuse box but the ECU doesn't want it. If the ECU matches the market of the car, then I would think there is a grounding issue or a short causing the alternator to kick high then normal then high etc.

All of this also makes me wonder, is the ECU actually chipped or did the seller keep the chipped ECU and throw some other ECU into the car to pawn it off to you?

Your title, sounds like you are saying you have a check engine light (CEL) on?

Another tidbit of info that may prove helpful is what model distributor do you have in the car? vtec is different than non vtec.