Is it possible to have a misfire w/o triggering a CEL?

 

Apparently the answer is yes. See picture taken from 96-98 Civic service manual.

[IMG]local://upfiles/25538/5ADD47ECD93B4543858FA76FE946884C.jpg[/IMG]

 

Damn, RonJ, you're fast. I've got one more question...The cylinder #s are 4-3-2-1 from left to right, right?

 

I don't know if it matters, but what year and model Civic do you have?

 

98 HX. D16Y5

 

Yes, when you are standing in front of the car.

The picture also may be helpful to you.

[IMG]local://upfiles/25538/2A1088DB692A4F7E8A3EB5F9B43EB233.jpg[/IMG]

 

I'm assuming the problem I'm experiencing is misfiring. I'm hearing a rough idle/popping noise coming from the exhaust.

 

Sounds misfire-like to me. Can you categorize the problem using the chart in the picture?



[IMG]local://upfiles/25538/5C238F8893DD455B8AC24ECBD8BD9137.jpg[/IMG]

 

Hehe. I was just looking at the same chart trying to figure it out. Here's the deal: I converted my CVT (which uses a standard narrow-band primary O2 sensor) to A 5-speed (which uses a wideband primary O2 sensor). I just put in the wideband O2 sensor today (which got rid of the CEL I had for several months) and I replaced my ignition wires w/ NGK wires today too. Since I'm not getting a CEL, I'm assuming my new O2 sensor is functioning properly.

So, that means it's probably the ignition wires, right? Should I pull them one at a time while running and see if the idle changes?

 

I think that's a good idea. Could you also verify by showing a lack of spark from the suspect wire?