I got a nice little OBDII scanner for my 97 Civic DX 5spd today to see why my check engine light was on. I have a crack in the exhaust manifold so I knew it would be the O2 sensor or emissions related. I was right, but to my surprise, I found that the ECU also recorded a cylinder 2 and cylinder 4 missfire. Then it shows P1300 which is a multiple cylinder misfire. The car is 100% stock. Not one modification.
That doesn't make sense to me because I replaced every component of my ignition with NEW parts and I reset the ECU by pulling the battery when I replaced the ignition. Not to mention, the car drives and idles wonderfully. The engine has 173,000 miles, but it runs like it has 60,00 miles. It doesn't hesitate or anything to make me even suspect a missfire. Even with the crack in my exhaust manifold I average about 33-36 mpg with 80% highway and 20% city, and 40mpg with 100% highway. I will be fixing the manifold down the road.
I really don't care to fix this problem. I'm just curious why the car would still be detecting a missfire.
I replaced:
Coil
Igniter
Cap
Rotor
Wires
Plugs
New distributor from Honda
I may be guilty, but I didn't set the timing when I installed the new distributor. I just put it in the same position. Would the timing being off have something to do with a missfire?
The previous owner also replaced the first O2 sensor early this year, but installed it in the cracked manifold. Could this have damaged the sensor?
That doesn't make sense to me because I replaced every component of my ignition with NEW parts and I reset the ECU by pulling the battery when I replaced the ignition. Not to mention, the car drives and idles wonderfully. The engine has 173,000 miles, but it runs like it has 60,00 miles. It doesn't hesitate or anything to make me even suspect a missfire. Even with the crack in my exhaust manifold I average about 33-36 mpg with 80% highway and 20% city, and 40mpg with 100% highway. I will be fixing the manifold down the road.
I really don't care to fix this problem. I'm just curious why the car would still be detecting a missfire.
I replaced:
Coil
Igniter
Cap
Rotor
Wires
Plugs
New distributor from Honda
I may be guilty, but I didn't set the timing when I installed the new distributor. I just put it in the same position. Would the timing being off have something to do with a missfire?
The previous owner also replaced the first O2 sensor early this year, but installed it in the cracked manifold. Could this have damaged the sensor?