Hey guys, I am new to the honda scene. In fact, I just sold my FRS today (bittersweet). I recently picked up this '90 EF sedan with an LS Vtec swapped into it.


It currently runs and drives (though it drives like **** and may be misfiring; needs a tune for sure), and the CEL came on after I got it detailed. There was some water that got down into the spark plug holes, but the guy cleared that out immediately with compressed air. The CEL stayed on after that, but I'm not sure if it drives any worse than it did before. But that is more beside the point.

This is what the ECU area looks like:









I am hoping I can gain a better understanding of what exactly is going on here, why things are wired/plugged the way they are, if this was done "correctly", why there are unused plugs, stuff like that. Any help would be appreciated. It is a p72 chipped & socketted ECU. Is this how the wiring is supposed to look when B swapping these chassis? Or is this a monstrosity that shouldn't have been done this way? Thanks in advance!

 

It appears that the underhood fuse panel has been pulled through to the interior. The plugs shown in your last photo are normally on the passenger strut tower. It's likely the wiring grommet on the firewall is damaged or just gone , I would check on that.
Pretty much all of this has been modified. What parts are you wanting to correct?

 

That is not how it should look if done correctly. If done correctly you shouldn't be able to tell much difference in how it looks when compared with the stock wiring. Looks like that is about as screwed up as you can get it.

 

This is a poorly executed wire tuck. You need to find the service connector, attach a jumper, and see what the CEL is on for (it could be multiple reasons, or "codes").

 

I see. Well, I'm not too sure. I mostly am looking to expand my knowledge base here and gain a better understanding of what this wiring situation is. If there's a somewhat easy way to clean this up at all without having to do any soldering or risk messing anything up, then I would be interested in pursuing that. I would like to get the CEL figured out first and get it running properly before attempting to tackle any of this.

Yeah, I noticed this ECU doesn't have an indicator light that blinks for CEL codes like the stock one does for these cars. Could you elaborate on that process? I'm not sure what you mean by the service connector or a jumper. Thanks.

 

Sure man. I'm guessing that it's been converted to OBD1. Those ECU's don't have the LED built into them to flash the codes. If the wiring is done properly, you'll jump the service connector and the check engine light on the dash will flash the codes. The service connector should be a 2-wire connector with a brown wire and a green/white wire which is tucked up under the dash all the way on the right side, to the right and underneath the glove box. Pull that empty 2-pin connector down and jump it with a paperclip, then turn the key to the on position and your check engine light should start flashing codes. The brown wire should go to D4 on the OBD1 ECU, or B20 on the OBD0 ECU.