eCtune

1 of the cars is a supercharged build B18c6 at 17Psi. I rather leave those 8's in But I can try if the mis firing stops with different plugs. I will keep you informed.

Yes, definitely don't go running at WOT with the wrong plugs! I just meant to pass inspection like you said .

i have these same problems when i run 8's i get small misses but if i get it around 14.1 they go away. kinda wierd i would like to figure this out aswell.

i have to idle at 14.0/13.8 to get to misfires. heat range 8 1000cc precission injectors

ok, so I am not the only one..... This car is running closed loop so at idle it will be around 14,7:1

i have these same problems when i run 8's i get small misses but if i get it around 14.1 they go away.

So at 14,1:1 it is performing better than at 14,7:1? So, running richer is solving the problem?

The 4554s are non projected so they don't sit as far into the combustion chamber and they come pre-gapped much smaller than stock, I think its like .025 or somthing, I don't know for a fact, but I believe the idle missfires have to do with the combination of these too things.. Small gapped plugs obivously increase leaner mixture missfires, but I'm sure the non projection adds to that. If your running a MSD or somthing like that the missfires go away.. You can also try gapping the plugs bigger, thats worked for me in some instances, but then you may get more breakup on top end, its a bit of a trade off.. 4554: Better combustion, less top end breakup, colder plug / idle missfires 7557: combustion interfearance, needs to be gapped smaller (electrode out of shape ) to prevent high end breakup with high boost / Better Idle quality. 4554 w/Ignition: Perfect. .. .

Ugh...I would never suggest running an MSD. I run 4554s in my car, I idle at about 15.6 and get the SLIGHTEST misfires. I'm also running RC550 High Imp Injectors...

Doesn't it depend on what MSD system you are running. I hear just running a MSD cap and coil is not as good as new factory honda cap and coil. Also Bosch coils put out bigger spark than MSD ones. So you can run MSD cap and Bosh coil. I myself run Stock honda on a N/A car

4554 w/Ignition: Perfect. .. .

Thanks for the info, but the supercharged car is already running with a MSD blaster coil and digital 6..... I think he just have to accept the mis fires at idle, and have to change the plugs for 7's when he is going for the smog test. Thanks guys!

I am also running the 4554's, an msd box, blaster 2 coil, msd cap, and plug wires and I am still getting those small misfires at idle until i richen it up to about 14.0. Also i put on a new turbo last night and am running .75 degrees of retard per psi with 110 gas and i could not get the car to stop breaking up. They are gapped to .028 with 17 lbs of boost on a pt67. Any suggestions? Smaller gap? more or less timing?(Timing should be more than safe with race gas?)

I hear alot of people don't like the MSd stuff, but I've never really had any issues with them.. If your getting breakup up top, try gapping your plugs down.. Or depending on how your motor likes it you can add a bit of timing in the breakup area.. usually I opt to gap the plugs down first. some cars I've had to go down to .016 to clear top end breakup.. Just depends on how healthy the ignition system is and how conservative your timing is.. Just my 2 cents.

Thats what i figured. I am going to put some fresh plugs in there and then gap them to .025 and see what it does. I dont think it has anything to do with my ignition setup because it did perfect with my gt3076r, the only thing i changed was i put a pt67 on there. Thanks again for your help.

Bugermass wrote:I hear alot of people don't like the MSd stuff, but I've never really had any issues with them.. If your getting breakup up top, try gapping your plugs down.. Or depending on how your motor likes it you can add a bit of timing in the breakup area.. usually I opt to gap the plugs down first. some cars I've had to go down to .016 to clear top end breakup.. Just depends on how healthy the ignition system is and how conservative your timing is.. Just my 2 cents.

My $.02... I have never had to gap a car running well, 18 psi or less, below a .32 gap. Maybe...if its over 18 psi, I would go to .26-28...but not usually. This is speaking strictly stock ignition. Out of all the cars that come in with MSD something or other on them, 60-70% have problems that ultimately end up being caused by the MSD. I dont install them so I dont know if the problems were ALL from installer error, but I would have to guess probably not.

I wonder whats so different about our tuning strategies that requires me to use smaller plug gaps due to missfires. Its not just me its other tuners here as well, its very common to have .18 to .22 gaps..

I'm usually right around .024-.025 when i get up into higher boost, but normally anything under 450hp i'm about .032-.035. From the maps i've seen from others, i'm pretty aggressive on the timing, but i typically tune to MBT on my dyno, i don't consider that aggressive though. Aggressive to me is getting every last hp you can squeeze outta it. Adam, First thing i would do, like burgermass said, is to gap a set of NEW plugs down, but .025 for 17lbs is pretty tight. If that doesn't do it, try taking some timing away, to see if it changes, if it gets worse you know your going the wrong way and to start adding timing, i'd do a degree at a time until it clears up, and then if on a dyno keep adding timing until your tq/hp gain on each increase starts to diminish, it should almost flatten out, then back it off a degree or two. If it doesn't clear up get rid of the msd crap, throw a stock dizzy(cap, coil everything) along with some stock wires and see if that clears it up. Now you said you had to richen it up to 14.0 to get it idle smoothly w/o any pops, if it idles smoother at 13.5, let it, I let the engine dictate where it likes to idle the smoothest, if it likes 12.5 afr (like my hatch does) i let it idle there, funny thing is the old school efi tuning books(accel dfi specifically) tell you to keep richening the idle until the rpms drop, then lean it back some.