Verkmiester

Hello all,
Just bought a 97 civic as a project car for cheap. It has a D16Y8 swapped into it with a p2p-c33 ECU and i believe is OBD2a (not sure if im right on that). Im new to honda's so im trying to get a grasp on wiring. I found a bunch of plugs not connected to anything.



The one in the middle i am 90% sure is for a Primary 02 sensor?
The header on the car currently has no 02 sensor in it...
The car is somehow running with just one sensor post cat.
I have bought a new header, which has the bung for a new 02 sensor i will buy, im hoping i can just install it? and the motor will run better?
The car has thrown the code P0135 and P0141.
This all leads me to believe the car is just completely missing a primary 02 sensor?

Secondly what would the other plugs be? i tried looking at a bunch of wiring harness guides and im at a loss as to what they are for

No clue if any of this will make sense but it's worth a shot.

The engine feels completely fine while driving so am i missing something here?

TracerAcer2.2L

It is possible that the ecu you have is chipped and thus you don't need o2 sensors. My car is tuned with neptune and I don't use them either. If emissions are not a problem for you, find out what exact kind of ecu you're running. If it isn't chipped or tuned, consider getting one that is that won't need the o2 sensors. No sense opening that can of worms if you absolutely don't need emissions

TracerAcer2.2L

As far as the other plugs go- I was in the same situation when I first picked up my junker swap car. Chances are you will not ever find a thread with all the sensors pictured with circles drawn around them and their names listed. So what I would do, is look up what all sensors come on the D series (many are the same as on most 90s hondas). After you get the names, look up pictures of them individually. Then go look over your motor very well and see what sensors you have and don't have, an exercise in learning your car. Here I'll start you out-

throttle position senor (TPS)
intake air temperature sensor (IAT)
manifold absolute pressure (MAP)
knock sensor
radiator fan switch
idle air control valve (IACV)
horn
distributor connections
coolant temperature sensor

JRCivic1

Both primary and secondary O2 sensor 4 wire plugs are in the picture, and I am not sure what the plug on the left is since I cannot see all wire colors in the plug. If you have an O2 sensor plugged into something behind your cat (the cat should be where your header is right up front when stock), follow the wiring back and see if it goes all the way to the ECU. A P2P ECU is not chippable, but the C33 suffix makes it Canadian, and the second O2 sensor may not be required (I am not up to speed on Canadian emissions requirements). P0135 and P0141 are codes for the Primary O2 sensor... and that one for sure is NOT plugged in based on the pic you provided.

Verkmiester

Thanks for the help guys, here is where im at. There is a confirmed o2 sensor after the cat. Basically the guy put an aftermarket header on and then a aftermarket cat thats welded to a strait pipe to a coffee can... haha.

What i did was ordered a complete exhaust from header to muffler, im going to attempt to install it today. Once i have this installed i am going to hook up a new primary 02 plus the secondary thats already on it now. Clear the codes and start er up. I do have a feeling something is jimmy rigged though because the car runs perfectly fine with just the one 02 sensor, plus the extra 02 plugs send red flags as well.

The reason im doing this is because i need the CEL to be gone for the insurance inspection. So even if the car works the way its set up now, its not gunna fly for the inspection. Unless i can convince the mechanic the CEL is inevitable with the way the car is set up etc. Since i fixed the other 10 things he needed fixed before he could pass it maybe he will be nice!

Will keep updating once i get the exhaust in.

TracerAcer2.2L

I wish you would have told us before spending all that money on stock parts! There are cheaper ways to get rid of a CEL. One possible solution is to pull the back up fuse for three minutes, put it back in and start the car. The CEL will go off, and if the ECU is rigged to accept a missing o2 sensor, the code probably won't come back for a while. Then you could get your inspection. Totally free

Verkmiester

Yea i didn't buy anything but the exhaust. Got the old one off at this point and sure and behold the 02 sensor behind the cat wasn't plugged into anything. So the car runs with no 02 sensors.