sims76 Posted June 8, 2005 Share Posted June 8, 2005 I have been experiencing misfires under boost (6 PSI and above) for the past month. I was running NGK BPR6ES-11 plugs and the stock NA coil. Yesterday, I put in NGK BPR7ES-11 plugs and a MSD Blaster 2 coil. No more misfires. Just thought I'd share. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted June 8, 2005 Share Posted June 8, 2005 probably much more to do with the coil than the plug change, no? I wouldn't think colder plugs would have any effect on misfire... well... a colder plug does foul easier so actually could cause or worsen misfire. Quote Link to comment Share on other sites More sharing options...
sims76 Posted June 8, 2005 Author Share Posted June 8, 2005 Bastaad, I would agree from a technical standpoint, but in my situation this problem took months to develop, so I'm thinking that either. 1. The coil slowly "weakened" if that's even possible. 2. The plugs had become slightly fouled, even though they appeared relatively clean IMO. I just hope the problem doesn't return. I actually cut all three of my dyno runs short around 5K RPM because I was experiencing these misfires. I would like to do another dyno session in the fall now that it's dialed in. Quote Link to comment Share on other sites More sharing options...
Thumper Posted June 8, 2005 Share Posted June 8, 2005 I would check the resistance of the spark plug wires and check the condition of the distributor cap and rotor. Sounds like the you weren't getting enough power at the spark plug. It could be caused from a weak ignition coil but usually they go bad because having alot of resistance down the line. If everything seems to be ok and in specs then you have fixed the problem. Just out of curiousity what gap are you running. At anything less then 12psi you should be able to run .040" with the msd coil. With the msd 6al and blaster 2 coil I ran .043 at 18psi. Good luck Quote Link to comment Share on other sites More sharing options...
sims76 Posted June 8, 2005 Author Share Posted June 8, 2005 Thumper, Cap and rotor look great, I guess I could place the rotor and measure the resistance from the tip of the rotor to the center electrode. Maybe I'll do that. I'll test the wires as well. I'm using 8mm crane cams wires. I left the plugs at the factory 0.044" gap. I'm running 12PSI, creeping up to 14PSI. partnumberkey.pdf Quote Link to comment Share on other sites More sharing options...
Clifton Posted June 9, 2005 Share Posted June 9, 2005 That's quite a big gap for 14 psi. Quote Link to comment Share on other sites More sharing options...
Thumper Posted June 9, 2005 Share Posted June 9, 2005 No really at 18psi I was able to run .050" but didn't want to push it so I backed it down to .043" This was with -11 ngks. Depending on what spark plugs you get that can make a big difference also. Also he is running a blaster 2 coil, and aftermarket ignition wires so that helps. Quote Link to comment Share on other sites More sharing options...
sims76 Posted June 9, 2005 Author Share Posted June 9, 2005 I took it out last night and ran it pretty hard, no misfires that I can feel. It's difficult to give it a good test on the road, because after a few seconds at 10+ PSI you're well over the legal speed limit. I guess that is not a bad thing as far as performance goes. I have to get to the track. This thing pulls hard, I'm very happy with this swap. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted June 12, 2005 Share Posted June 12, 2005 I run a .050" gap on NGK 7's. I get NO misfires under boost. I'm also running an MSD 6A and Blaster 2 coil. This is at 13 psi though I've run as high as 15 briefly. I've heard/had misfire at idle... I know the sound, like random, intermittent pops from the exhaust. But I can't even imagine what it would sound like under boost or at high RPM... could someone possibly describe what it would sound like? Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 12, 2005 Share Posted June 12, 2005 "FACTORY GAP"!?!?!?!?!?!?!?! I don't believe in "factory gap" and the fallacy that one exists has been proven every time I open a new set of plugs! NOTHING goes into the engine without being checked physically and verified at LEAST! But back to the question, I agree with Thumper, for lower boost you should be fine at .040 or thereabouts. I am at .043 with no misfire problems at 17psi. I do have problems with WIRES though! They are replaced regularly. When that happens, the misfires go away. Really kills me, too! They usually "look" great, but when Ohmed, have broken down internally. Carbon Fiber supression wires, BTW. To recoup my plug wire expenditures, I save them all, put them in a box, and let my wife put them out during her yard sale. Serves a purpose: makes her think I am "selling off some of that car crap lying all around here" therefore preserving my hobby status at home! LOL Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted June 12, 2005 Share Posted June 12, 2005 I do have problems with WIRES though! They are replaced regularly. When that happens' date=' the misfires go away. Really kills me, too! They usually "look" great, but when Ohmed, have broken down internally. Carbon Fiber supression wires, BTW.[/quote'] Why are the wires breaking down? Have you ever tried Magnacore wires? They seems to least the longest and work the best. For me atleast. Quote Link to comment Share on other sites More sharing options...
Thumper Posted June 12, 2005 Share Posted June 12, 2005 I 2nd magnecore wires. Have run them on most of my cars and never had a problem. I have been running them on z for six months and thats with a ms6al and blaster 2 coil putting higher than stock stress on them. Ted Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 12, 2005 Share Posted June 12, 2005 Carbon Supression Wires. I know the Tec2 System specifically recomends Packard Supression wires, and also says to treat wires as a consummable item. Thus Far they have been correct. I am suprised by how long recently purchased items seem to last, while the JDM Fat 8mm Supression wires I have on my 73 ZX(T) have been on there since 1989 and they are still working FINE at 17psi! Quote Link to comment Share on other sites More sharing options...
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