Lasky

To start off the car is a 95 civic ex with a jdm b16 in it..

Alright so ive had a check engine light for about a month now and I figured it was my O2 sensor since it would only come on after about 10 minutes of driving. My ignition coil has failed about 3 times in the past month (thank god for a warranty) and my spark plugs have been covered in carbon every time I looked at them. So I replaced the O2 sensor and plugs yesterday and the check engine light comes back on first drive I go on today.. I check to see what codes the car is throwing and its throwing code 41 and 23.. 41 is O2 sensor/ O2 sensor heater and 23 is knock sensor.. I haven't had the knock sensor wired up since I put the engine in 3 summers ago and I just put a new O2 sensor in yesterday.

Any ideas on whats going on would be of great help its getting rather frustrating breaking down out of nowhere every week or so...

Former User

If you clear codes from the ECU, do both CEL codes return? You need to fix both of those codes.

With that said, these codes most likely are not causing the coil to blow. Before installing a new coil, make sure the plugs, wires, cap, and rotor are in very good shape. Also inspect the inside of the distributor for damage, burning, dust, oil, or missing parts (e.g., inner cover).

strategy400

I ignored a knock sensor CEL once and a piece of one of my valves broke off. Fix that immediately.

Fliptard

Knock sensor detects issues (knocks) in the motor and causes the car to not run, or run right at all and can cause serious engine damage, Wire it up!!

Lasky

I understand what the knock sensor does just wondering why after 3 years of driving it just decided to come on and throw a code - also if there is no knock sensor wired up how would the ecu know if the engine is knocking or not?

I pulled the back up fuse for 20 mins yesterday and codes still come back

i am missing the inner cover to the coil, but it was missing from hmotors when i bought the motor years ago and never caused a problem until recently

I was wondering if since the b16 is supposed to run two O2 sensor and not just one if that would be a cause of some problems?

Also car runs like its in limp mode, feels like i have less power throughout entire rpm range

Lasky

also just found a small bit of corrosion inside the plug to the O2 sensor.. only on one of the connecting points.. dont know how to fix that or if that could be a reason for the O2 sensor to still be throwing a code

Former User

Things break.

A few possibilities to consider:
-Broken knock sensor
-Bad knock sensor wire
-Bad ECU

You will continue to blow coils if you don't install an inner cover. All parts have a purpose.

Lasky

Ok ill have to source an inner cover for the coil very soon

however the knock sensor has never been wired in and is still not connected, so how would the ecu know if the engine was knocking

basically theres no connection from the knock sensor to anything its just sitting in the motor with no wires running to it

thanks for the super fast reply

Former User

Check the local junk yards.

Well this^ obviously explains the KS code. Wire it up and you should be good to go.

Lasky

just wondering why it took 3 years for the ecu to realize there was no knock sensor wired up?

Lasky

the cel has only been on about a month, ive had the swap in for the past 3 summers

Former User

Sounds like you've had multiple problems that would throw CEL codes, so I must presume that either you haven't noticed it or that the CEL itself is not working properly. Regardless, you are now aware of several problems that must be fixed if you wish to maintain your car.

Lasky

ok update on the situation.. ignition coil has inner cover not sure if its possible to install an ignition coil without it.. i was thinking of the 'leak cover' which is missing from the inside of the distributor.. all wiring seems to be in good shape with nothing looking out of the ordinary inside the dizzy

the inside of the plug that runs from the engine harness to the O2 sensor has a small bit of corrosion on one of the contact points on the inside.. could this be the cause of the code 41 even after a new O2 sensor has been installed.. also does anyone have any advice on how to remove the corrosion without having to wire in a new plug from the junkyard

Also just bought a new knock sensor and some shielded wiring to wire up the knock sensor.. was wondering if the fact that code 23 is on and its retarding the timing, hence the lack of power, if this could cause the ignition coil to keep failing

ill post an update tomorrow once knock sensor is wired up and i clear the codes again

Former User

We are both talking about the inner cover/leak cover. It is possible to install the coil without. Don't run your car until you have found one and installed it.

Former User

It's possible. Have you measured the resistance of the O2 sensor heater element?

The lack of a knock sensor would not blow the coil.

92ehatch

when i first swapped my z6 into my hatch i had 2 map sensor harnesses, one from the z6 and one from the car's factory harness.

i plugged the wrong one up and drove it for months, then took it to the track and the CEL popped on.

plugged the other wire harness in and it worked fine for the rest of the time.

i dont know why, but it took a couple of months to realize the map sensor wasnt plugged in. strange but possible.

Lasky

shittt, alright ill have to hit the junkyard up to find an inner cover

Im still confused on why it took so long for the car to start running so bad and having these problems.. I guess it doesnt matter why it took so long and I need to fix it just baffles me that 3 years down the road is when it starts to act up on me

thanks for all the help and quick responses ron I really appreciate the insight

Lasky

I see what your sayin but this has been yearsss..

knock sensor just arrived at autozone so im gonna go scoop it and wire it up later today and see what happens

Lasky

one last question ron, are you saying that the lack of an inner cover could be causing the ignition coil to keep going bad? like its overheating or something?

Former User

The lack of an inner cover may blow the coil, so you need to fix that. The inner cover prevents the high voltage generated by the coil from throwing sparks all over the inside of the distributor. It serves as a form of electrical insulation in a high voltage environment.

Lasky

ok so leak cover has been installed and knock sensor has been wired up, im letting the car sit without the back up or ecu fuse in for about ten minutes then im going to start the car let it warm up and take it for a test spin and hopefully no more problems..

ill post up later with results.. hopefully all goes well

also i scooped an extra O2 sensor harness end, the side that goes into the harness not the side that connects to the O2 sensor itself.. i was going to cut and rewire all four wires to get rid of that corroded plug but dont know if that will mess with the O2 sensor readings.. any input would help on that too

thanks guys

Lasky

well after resetting the ecu and letting it idle learn again the car has no codes, somehow by installing the knock sensor it cleared the O2 sensor code as well.. car is running much better and ignition coil hasnt blown yet

i still have a 200-300 rpm idle surge after driving the car for about 20 minutes like theres a vacuum leak or a bad O2 sensor but theres no codes and i checked everywhere for a vacuum leak yesterday and couldnt find one.. any ideas on what that might be would help

thanks again for all the help ron, really appreciated