suzuka_blue_s2k

I have a 2006 s2k with 46,xxx miles. About 7,000 of those miles with a CT Engineering SC installed (purchased brand new). A while back I got a check engine light for a P0304 - Cylinder 4 Misfire. I cleared it and some time went by before it returned. Then recently it started happening daily. So I finally decided to try and diagnose the problem by doing the following:

Injector for cylinder 4 swapped with cylinder 3
Spark plug for cylinder 4 swapped with cylinder 2
Coil for cylinder 4 swapped with cylinder 1

Now I have CEL for P0303 - Cylinder 3 Misfire and P0404 - Cylinder 4 Misfire and P0300 - Random Misfire. I can't really figure out what conditions cause the CEL but it seems like it happens at idle or decelerating.

The kit came with RC650cc injectors, 1 step colder plugs, and I'm running the calibration that came with my flashpro. CT Engineering says its a safe tune...any other relevant info you guys need??

Thanks

s2000Junky

Wouldn't be surprised if it was one of the RC injectors. Try moving that same injector to cylinder 2 now and see if it follows again.

suzuka_blue_s2k

^I'll try that. But yeah I was hoping that I would get just one code after moving things around but was confused why I still have the cylinder 4 misfire along with cylinder 3 and random misfire?

s2000Junky

Random or multi misfire isn't uncommon to trip when more then one cylinder misfires. You could have 2 of the 3 issues you presented happening. Just have to start from the easiest and most likely and narrow it down from there.

suzuka_blue_s2k

So here is what has happened so far...

CEL = Misfire Cyl 4.

Moved injector in cyl #4 to #3
Moved spark plug in cyl #4 to #2
Moved coil in cyl #4 to #1
Got a CEL = Misfire Cyl 3 , Misfire Cyl 4, & Random misfire

Moved injector in cyl #3 to #1
Moved injector in cyl #4 to #2
Got a CEL = Misfire Cyl 1

Can it be a dirty injector?

s2000Junky

That would be my guess. Doesn't cost much to send them in for cleaning and see if solves the problem, or one of them.

suzuka_blue_s2k

I'm going to run an injector cleaner through the fuel system and see if that takes care of it. My data logs show a rich condition under load (the stock wideband reads to 10.14 and it looks like I'm out of range). At what point do you foul up the plugs?

Also what's he ap2 fuel pump lph rated at? I may just go to a smaller pulley and get a custom tune.

s2000Junky

Your running way too rich if thats what your reading. Your not burning clean at that afr. Aim for mid 11's to 12afr. If the problem persist then see about injector cleaning. Also more fuel puts more duty on your spark plugs to ignite the mixture, and if your running a wider gap on the plug it will have less duty to burn an overly rich afr fouling your plugs prematurely. However too small of a gap and they wont burn as efficient in partial load/light duty. Make sure your fuel tuning is proper first. Look at your plugs and make sure they aren't fouled, clean or replace if needed after afr is correct. Make sure gap is in a good range as well.

suzuka_blue_s2k

Injectors went out for testing and flow was spot on...

now to try and get the tune dialed in.

suzuka_blue_s2k

I street tuned the car to 11.5 AFR at WOT. I've even replaced the injector plug and play connectors. Still getting misfire...I think it only throws the code when ECT starts to reach 200 deg (like at a drive thru). I see misfire codes often also when the engine is warm and I turn off the car, run in the store and come right back out and crank it over and drive off.

I'm doing a compression test tomorrow...