Greetings everyone.. I am new to these forums and to the Honda crew. After picking up my 98 Accord I found that the engine light was on. I checked the code and got code 23 (knock sensor) as I looked up the code. The engine light isn't ALWAYS on.. It comes on all the time but sometimes it takes longer than others for it to switch on.

Would this be either due to the fact that it could be a dirty knock sensor and just needs to be cleaned? Could it possibly be the fuel or would the ECU hit the burned fuel straight away and come on at the first point of me turning on the car? I also have a pretty busted crossmember (front passenger near the sway bar) so it really rattles when I go over bumps. Also the engine light seems to pop up more under the throttle around 3k-4k rpm in 1st gear (usually when I notice the light on) sometimes I can be 5-10 minutes up the road and the light finally turns on. Also the oil seems to be a little thin, I think the person before me has used maybe a thinner oil than what should be used (I am guessing this one though) just from a quick examination of the dip stick.

I am more than happy to replace the knock sensor but would like to steer clear of that as much as possible and I am searching for a front crossmember as we speak.

 

It's entirely possible that you have an intermittent open in the wiring however I would say it's more likely the knock sensor itself is bad considering it's happening after a given rpm range.

 

Would a faulty knock sensor stop vtec from kicking in?

 

Yes, it will. Does your car go into limp mode when it throws the code ?

 

By limp mode you mean the car losing power? Then yes.. It seems that it doesn't have as much power as it should and really seems sluggish and surges sometimes especially in 2nd will pick up revs sputter a tiny bit and then pick up revs again. I also think the oil might be a bit thin and that is also stopping vtec from engaging. I haven't tried putting my foot down because of the engine light. I should have a sensor on Thursday and will let you know if the engine light still comes on.

 

Check to see if the plastic connector part of the sensor has separated from the metal body. That's happened to me TWICE in six months. What really sucks is how flipping expensive they are!

 

So today I got my new knock sensor, I put it in, cleared the codes.. Took it for a bit of a drive, the CEL came back on still and I turned the car off, check the code, knock sensor code.. Cleared the code again and than it didn't come on for ages and than the CEL light randomly came on.. Only doing 90kms in 5th gear along the highway, nothing fancy just came back on.. Turn the car off and it stays off for a while but it may come back on.. Any ideas?

 

What you are going to have to do is to find the exact pin for the knock sensor at the ecu connectors and then test for continuity from the knock sensor connector back to that pin. Wiggle the wiring around a little bit and see if it breaks continuity. Provided it does, you will need to get some shielded wire(you must use shielded wire as the knock sensor is very susceptible to radio interference) and peel back some of the sheath and run some wire with a connector to that sheath and the other end with a connector to ground somewhere on the frame.

However, if there is perfect continuity no matter how much you wiggle the wire it's likely the ecu is bad. It's possible the pin on the knock sensor connector is bad so check it thoroughly for corrosion.

 

Could it be possible that the ecu was just adjusting to the knock sensor.. I have taken my car for a fair bit of a drive today and the light hasn't seen to come back on as of yet (touch wood)

 

If you cleared the codes and the light came back on again then you still have an issue. I'm just going by the fact that you said you cleared the codes and it came back on.

 

Well it's been a few days, zero engine light and I say that the problem is fixed. I don't really know what the issue was as to why it was still coming on after clearing the codes but I haven't seen it again and I can only assume that the problem is fixed. Thank you for your help with this issue it has been much appreciated

 

It's entirely possible the connector was either corroded or was not completely plugged in.