Slight Missfire under boost
#1
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Slight Missfire under boost
Recently I have been having missfire issues under boost. I took out my spark plugs and they were fouled so I put brand new ones in there that are gapped to .021, just like my old ones were. Now it doesn't missfire as bad but its still missfiring a little bit. its a Built D, Vitara Pistons, z6 head, 13PSI on a ebay t3/t4. its tuned and has been running fine for about a year. This problem only recently started happening. I also have an external MSD blaster coil. The spark plug wires are also fairly new with them being less than 2 years old and in perfect condition.
#3
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Re: Slight Missfire under boost
well the cap and rotor are about a year old, both MSD. And the ICM is brand new. I am thinking it has to do with a fukd up VTEC Oil pressure sender. Because when the sensor is working it seems to be fine. But as soon as the sensor starts acting up it starts again.
#4
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Re: Slight Missfire under boost
K well I fixed my vtec, and it's not that. The missfire/stumble is getting worse again. But it's not constant. The longer the car runs the worse it gets, but only under boost.
#5
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Re: Slight Missfire under boost
idk if its true but i've heard over and over that MSD products don't work well on Hondas. you may want to swich your cap and rotor back to OEM temporarily and see if the problem still exsists. if so, try runing without the MSD blaster coil. Honda engines are extremely tempermental when it comes to their ignition systems.
#6
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Re: Slight Missfire under boost
idk if its true but i've heard over and over that MSD products don't work well on Hondas. you may want to swich your cap and rotor back to OEM temporarily and see if the problem still exsists. if so, try runing without the MSD blaster coil. Honda engines are extremely tempermental when it comes to their ignition systems.
#7
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Re: Slight Missfire under boost
that may be possible as well. but i would assume the blaster coil would last longer than that. do you have upgraded spark plug wires as well? another option is maybe the wires are starting to get weak?
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#8
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Re: Slight Missfire under boost
the wires are NGK replacements and were replaced about 12k ago. They are fine on both sides of their connectors, so I doubt its those.
#10
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Re: Slight Missfire under boost
ya im leaning more towards coil, because it gets worse the longer that I run the car without letting it fully cool down.
#11
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Re: Slight Missfire under boost
ah i see. yeah i would try using an OEM cap and rotor. if its true that MSD parts don't work well on Honda then this would make perfect sense. you can probably get away with keeping the blaster coil. but I've heard bad things about using both aftermarket and other non Honda replacements when it comes to cap and rotor. my engine is 23yrs old and has over 280K miles so I never use anything other than OEM Honda so personally i couldn't tell you.
#12
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Re: Slight Missfire under boost
ah i see. yeah i would def check the cap and rotor. if its true that MSD parts don't work well on Honda then this would make perfect sense. you can probably get away with keeping the blaster coil. but I've heard bad things about using both aftermarket and other non Honda replacements when it comes to cap and rotor. my engine is 23yrs old and has over 280K miles so I never use anything other than OEM Honda so personally i couldn't tell you.
#13
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Re: Slight Missfire under boost
i had this same problem
i took off the oem cap and coil
msd cap and coil went on and it was like butter.
you sure did gap those plugs real low but that is of course a dif build then mine.
is your A/F ratio consistent as temps rise?
i took off the oem cap and coil
msd cap and coil went on and it was like butter.
you sure did gap those plugs real low but that is of course a dif build then mine.
is your A/F ratio consistent as temps rise?
#14
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Re: Slight Missfire under boost
well they have to have a low gap for boost. That is the gap that my tuner told me to run, and its a pretty standard gap for turbo cars. I am not sure about my A/F ratio because I don't have a wideband. My ECU takes care of the A/F ratios and if it goes out of spec it will cut ignition. Its not pinging though, its just missfiring.
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#17
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Re: Slight Missfire under boost
misfiring at high rpms?
higher the gap the better for turbo cars.
i ran a .030-29.
i remember when we were tuning my car and it was acting up and we gapped some new plugs even more to .030 from like .022 or sumthing and it was better.
then we had the other problem which the cap and coil fixed....
try a more of a gapped plug and see if it helps....if it doesnt just go back to your other ones but its an easy fix if thats what it is.
higher the gap the better for turbo cars.
i ran a .030-29.
i remember when we were tuning my car and it was acting up and we gapped some new plugs even more to .030 from like .022 or sumthing and it was better.
then we had the other problem which the cap and coil fixed....
try a more of a gapped plug and see if it helps....if it doesnt just go back to your other ones but its an easy fix if thats what it is.
#18
Honda-Tech Member
Thread Starter
Re: Slight Missfire under boost
misfiring at high rpms?
higher the gap the better for turbo cars.
i ran a .030-29.
i remember when we were tuning my car and it was acting up and we gapped some new plugs even more to .030 from like .022 or sumthing and it was better.
then we had the other problem which the cap and coil fixed....
try a more of a gapped plug and see if it helps....if it doesnt just go back to your other ones but its an easy fix if thats what it is.
higher the gap the better for turbo cars.
i ran a .030-29.
i remember when we were tuning my car and it was acting up and we gapped some new plugs even more to .030 from like .022 or sumthing and it was better.
then we had the other problem which the cap and coil fixed....
try a more of a gapped plug and see if it helps....if it doesnt just go back to your other ones but its an easy fix if thats what it is.
#20
Man U FTW
Re: Slight Missfire under boost
See if you can't find another dizzy and try that just to eliminate any distributor-related problems. If the misfire ceases, you know where your issue lies.
#21
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Re: Slight Missfire under boost
Well my dizzy is Frankenstein. Its a OBD-1 Z6 dizzy, with a OBD-2 Y8 Interface so that it plugs into a OBD2 harness. So no dizzy actually fits in the car. :/
#22
Man U FTW
Re: Slight Missfire under boost
Yikes...nothing like modifying Hondas lol. My car is hardly able to be serviced at an Acura dealership after all the crap i've done to it...i feel your pain on that one. Good luck with the coil swap
#23
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#24
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Re: Slight Missfire under boost
I hope this thread isn't dead.... I am running a stock B16 on 12psi.... when tuning we ran into the problem and solved it by installing a set of NGK wires, it was fine for a month or two and then the problem came back. The ignition was stock so as advised by SlowMotion (they tuned my car) I replaced the ignition coil(msd), cap(msd), rotor(msd), and plugs(ngk gapped at 0.21ish), car ran great for a day and then it came back... I'd love to find the solution to this issue, its driving me crazy!!
Thanks to anyone who has words of wisdom
Thanks to anyone who has words of wisdom
#25
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Thread Starter
Re: Slight Missfire under boost
I hope this thread isn't dead.... I am running a stock B16 on 12psi.... when tuning we ran into the problem and solved it by installing a set of NGK wires, it was fine for a month or two and then the problem came back. The ignition was stock so as advised by SlowMotion (they tuned my car) I replaced the ignition coil(msd), cap(msd), rotor(msd), and plugs(ngk gapped at 0.21ish), car ran great for a day and then it came back... I'd love to find the solution to this issue, its driving me crazy!!
Thanks to anyone who has words of wisdom
Thanks to anyone who has words of wisdom
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