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Help with OBD1 B18C1 into 94 Hatch (CARB / Check Engine)
Hi, Needing some help regarding a check engine light related to code 23 (Knock Sensor) on my swap. I've listed the car's specs below, along with photos to hopefully get a quick answer to my issue. The car is Bar'd for the B18C1, however I'm told by a smog shop that the check engine light must not be on or it will auto-fail smog test. In addition, you can't just take out the light bulb for the check engine light as the light MUST light up when you turn the ignition key, and then remain off the rest of the test.
1994 Honda Civic Hatchback CX Block: B18C1 GSR Head: PR3-1 with "96" as the year -> Is this a B16 or a real Type-R head? I was told when I bought the car it was actual Type-R but who knows.. Intake: B18C5 Type-R ECU: P72
I do NOT see a knock sensor underneath the intake runner on the back of the block. You will see in the photos where the wiring harness is ziptied up and the connector in the ziptied harness that isn't connected is in the general area of where it could be plugged into a knock sensor...
In the 1st photo below there is another wire that is coming off the main wire harness and I'm not sure the purpose of that either?
My question is, how do I turn off this CEL from blinking so that I can pass my smog test which is due in the coming 2 weeks???
Re: Help with OBD1 B18C1 into 94 Hatch (CARB / Check Engine)
Thanks for that.. I'm trying to figure out a permanent and legit solution so that I can pass smog in CA without issue. It seems that my options are:
1. Chip the P72 ecu to delete the knock sensor. But if they visually look for the knock sensor and it's not there then I'll fail.
2. Install a knock sensor into the block. Not sure if this is doable if there is no provision for a knock sensor to begin with, eg. - is there a particular spot the knock sensor should be installed.
Re: Help with OBD1 B18C1 into 94 Hatch (CARB / Check Engine)
There is a hole where the knock sensor should be you just need to buy one and thread it in. Also that connector you showed that is green is probably for the power steering pressure switch but list the colors and confirm that.
Re: Help with OBD1 B18C1 into 94 Hatch (CARB / Check Engine)
Thank you for your reply. That makes sense about the power steering as I do not have power steering.
I've spent about 6 hrs researching knock sensors and I get conflicting g information...some say all b series vtec motors have knock sensors, and others say they dont. I've looked at the back of the block 3 times and haven't seen a location for the knock sensor to plug into but I guess I'll check one last time.
I just read on another site that you can drill and tap a hole for it....hopefully there is a hole for it already. I already spent $100 at autozone for a new knock sensor so it's ready to go in.
Re: Help with OBD1 B18C1 into 94 Hatch (CARB / Check Engine)
Yeah, I thought that was it too, so I bought a new knock senor and the threads were way too small to fit. It turns out the knock sensor I bought from autozone was actually a oil pressure sensor.....I just got back from returning it after figuring that out.....It had the correct box and wrong part. I'm hoping the knock sensor I ordered from O'Reillys will have bigger threads and will screw right into that spot. Assuming it does, my next step will be to wire it up. I checked the electrical plugs again dangling at the back of the block, and turns out there is another plug which is black/dark grey. I'll check wire colors later today when I go pick up the new knock sensor. Thank you for your help.
Re: Help with OBD1 B18C1 into 94 Hatch (CARB / Check Engine)
So it turns out after getting the knock sensor from oreillys that it does indeed fit the hole in the back of the block underneath the 2nd cylinder from driver side. Threaded in perfectly. I'll be installing it tomorrow, and plugging it into the electrical connector that is still present (I'll double check wire colors first). Fingers crossed it all works out ok and no codes or additional wiring needed!
Re: Help with OBD1 B18C1 into 94 Hatch (CARB / Check Engine)
Installed knock sensor, connected grey plug that had red/blue and black wire going to it. Drove car still got CEL. I probably need to disconnect battery for 10 mins to reset ecu. I know the connector should only have 1 wire (red/blue) and not the black presumably ground wire.
Re: Help with OBD1 B18C1 into 94 Hatch (CARB / Check Engine)
The knock sensor will only have 1 wire. That wire you connected sounds like it could be the IAB wire connector (for GSR engine although I don't know what engine harness you're using) although I can't be sure, I am sure that the knock sensor connector only has one wire in it, no ground wire. If you can't find it you may need to wire it directly to the ECU.
Re: Help with OBD1 B18C1 into 94 Hatch (CARB / Check Engine)
Ok, so I installed the knock sensor, plugged in that 2 wire connector. Check engine light was coming on, I reset battery and drove a couple times, still code 23 bad knock sensor. So yeah I need to apparently run a new wire from knock sensor to the ecu. I'll need to do that this week. Thanks for your help, I'll keep this updated.
01-09-2015, 01:48 PM
Help with OBD1 B18C1 into 94 Hatch (CARB / Check Engine)
