Reacuring Missfire in Cyl 1

Char · Nov 6th, 2005, 04:16 AM

So Ive had this car for about a month now.. It runs well, 146K miles. Right after buying it I replaced the Spark Plugs, Plug Wires, Distributor Cap and Rotor, PCV Valve, and Fuel Filter, Engine and Tranny Fluid. Little later I replaced the Knock Sensor (old one was bad) and the whole exaust expect the headers and catback (old pipes and muffler were rusted to shit).

Well.. My check engine light started coming on about a two weeks ago when I finally got around to driving it a lot more. Pulled the codes (work at a gas station, using the real things here) and I was getting a Cyl 1 missfire and knock sensor. We though the sensor was kicking off the light so we checked it, was bad, replaced it. We were still getting the missfire (though only once every few "ignition cycles", last time was 7 starts since it happen) and it annoyed him to the point he moved the plug to another cyl, checked the wire, checked the compression, cleaned a bunch of stuff (I was working while he did that part) and he still cant find out why. So we dont know what to do.. we chose to leave it for now, it wasnt causing any problems while driving or anything, didnt even feel it.

I was driving a couple hours ago.. just aimlessly, around 2500rpms in 5th gear.. the check engine light went crazy, flashing a lot (though not eratic) then stayed on. I turned right around and parked it home. I know I cant really get it scanned till Monday, but Im really worried now. I cant think of what it could be and hes annoyed to the point I doubt he wants to see it again. This is my first car and Im already madly in love with it, I dont want it to have such a serious problem.

Does ANYONE have a clue what it could be or what to check out? I know I can count on this guy about all this stuff.. hes ASE certified and has been working there for some time, I trust him with my car, but short of taking the engine apart hes stumped. But he doesnt really know much about my car or their engines other then ones he may have worked on before or what AllData will tell him, being a Honda guy himself.

Wow this became long. Anyway... help? x.X

Hydrolock · Nov 7th, 2005, 07:29 PM

The flashing check engine light while your driving indicates a type A misfire which is the worst out of three types of misfires. It indicates a misfire was happening within 200 revs of the crank, and it can cause the cat to heat up beyond 1600 degress and do damage to it.

The car stored freeze frame data on the scan tool of all operating parameters when the misfire occured which can be helpful in diagnosing a problem.

Did you tune your car up with QUALITY parts? Autojunks tune up parts can cause problems right out of the box. Don't rule something out just becasue it's new.

Next I would either hook it up to an ignition scope or a 4-5 gas analyizer.

The ignition scope will help you pinpoint any abnormal things going on in your firing of the spark plug. You can see the firing line, spark line, coil occilations, dwell, and transitsor on/off from this. Maybe spray some high volt on your wires to see if they are leaking. If nothing is spparently wrong on the secondary ignition side of things, I would go to the exaust gas analyizer.

Is it a rich misfire? Is it a lean misfire? Is it running too hot? If you still coming up with nothing worn camshaft, broken/weak valve spring, basically anything in the valve train that would cause uneven firing of the cylinders, and lack of compression.

If this guys ASE certified he should be able to do these things an interpret the readings, only problem is can you get him to hook you up this good, cause this ain't part of your 20 dollar tune up ya know? Good luck bub.