Hondata

I have K20A2 engine + CAI + K100. I get misfire on cylinder no3 (P0303) since the beginning of cold temperatures (I leave in Quebec). When I start the engine for the first time of the day (generally by a cold morning), CEL turn on. When engine is partially to completly warm, CEL never turn on! Honda told me the code was P0303. After many test, Honda told me that spark plugs, coil pack and injectors seem to be ok.

When CEL is on, idle is stable but when I listen to the muffler, I can hear the sound of the engine running only with 3 cylinders. Is it possible that my program doesn't like winter????


By the way Doug, I'm the first EP(white) you tuned when you came to Montreal this summer! Maybe you remember me now! :)

Try moving your injectors around and see if the problem follows that injector.

Spunkster wrote:Try moving your injectors around and see if the problem follows that injector.

Already done by Honda!

Replace the spark plugs, then check for spark strength on each plug. Swap the injectors around, and also the injector plugs to eliminate the cylinder trim and injector wiring. Don't trust Honda to do this - get someone knowledgeable to work on the car.

Hondata wrote:Replace the spark plugs, then check for spark strength on each plug. Swap the injectors around, and also the injector plugs to eliminate the cylinder trim and injector wiring. Don't trust Honda to do this - get someone knowledgeable to work on the car.

How does one check for spark strength? I'm no mechanic. This also isn't my thread, but I'm curious none the less.

You look at the spark and see what color and how far of a gap it will jump.

Spunkster wrote:You look at the spark and see what color and how far of a gap it will jump.

I thought there was something more scientific then just looking at it!!!!


By the way, I'm about to buy a used Type S ecu to see if this damn CEL will still turn on! If I get no more misfires, my conclusion would be that my engine is OK, and would focus on the programation. If it's still turn on, engine has problem and .... that would suck!!!!!!!

What do you think about that?

That will give you more informatiln to look at and is a good step in the trouble shooting process.

Ok! Honda swaped the ecu for the stock one.... and I have the same problem! :evil: But now, I'm sure the problem is not my K100! :)

But something weird happen! When "Honda diagnostic computer" is plug in my car we can see live what happen with the engine while it's running. If misfires happen, we can see it with the misfire calculator. So here is what happen: At idle (775 rpm) Honda computer see misfires and count it like 1... 2... 3... .....10... 11...12... and CEL turn on. But, if I press gas pedal and set rpm at 850, 1000, 2000, 2300, 4000 or 4500rpm, ENGINE HAS NO MISFIRE!!!!! As soon as engine come back to idle (775rpm), misfire come back!!!!

What do you think about that :shock: ???

200HP EP wrote:Ok! Honda swaped the ecu for the stock one.... and I have the same problem! :evil: But now, I'm sure the problem is not my K100! :)

But something weird happen! When "Honda diagnostic computer" is plug in my car we can see live what happen with the engine while it's running. If misfires happen, we can see it with the misfire calculator. So here is what happen: At idle (775 rpm) Honda computer see misfires and count it like 1... 2... 3... .....10... 11...12... and CEL turn on. But, if I press gas pedal and set rpm at 850, 1000, 2000, 2300, 4000 or 4500rpm, ENGINE HAS NO MISFIRE!!!!! As soon as engine come back to idle (775rpm), misfire come back!!!!

What do you think about that :shock: ???

Well... I'm not a 4 stoke engine mechanic, but I can tell you in the nitro powered rc car world, when an engine started missing and dying at low rpm it was losing compression and time to replace the piston and sleve. If you have verified that the problem isn't localized to one ignition coil, plug, or injector, that pretty much leaves something wrong with that cylinder. Have you done a compression test, or better yet, a leak down test? I don't want to jump to conclusions, but if you have ruled out the tune, the injectors, the plug, and the coil, it's time to start looking to mechanical issues.

Razathorn wrote:
Well... I'm not a 4 stoke engine mechanic, but I can tell you in the nitro powered rc car world, when an engine started missing and dying at low rpm it was losing compression and time to replace the piston and sleve. If you have verified that the problem isn't localized to one ignition coil, plug, or injector, that pretty much leaves something wrong with that cylinder. Have you done a compression test, or better yet, a leak down test? I don't want to jump to conclusions, but if you have ruled out the tune, the injectors, the plug, and the coil, it's time to start looking to mechanical issues.

Well said