I just changed the spark plugs (NGK PFR6G-11) last night, and now I am getting random misfire from the spark plug. When it misfires, the car shocks a little. It is like someone slightly bump the car from behind. This misfire occurs around 5 time a minute, but sometime it does not do it at all.
Any suggestion on how to fix this?
I am thinking remove all spark plugs and reinstall them again.
nonrandom spark plug misfire Q45
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Checkered-Member
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Re: nonrandom spark plug misfire Q45
do that...VA99Q45 wrote:I am thinking remove all spark plugs and reinstall them again.
then report back to us...
I just removed and reinstalled 4 of the 8 spark plugs. Test drove it, and it still misfired.
I will do the rest tomorrow.
Is there a way to test the coil pack with a voltmeter?
Is there much difference between the cold spark plugs vs the standard or the hot spark plugs? My new spark plugs are the "cold" spark plugs.
I will do the rest tomorrow.
Is there a way to test the coil pack with a voltmeter?
Is there much difference between the cold spark plugs vs the standard or the hot spark plugs? My new spark plugs are the "cold" spark plugs.
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HeavyDuty
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95 Nissan 240SX S14
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Why are you using a colder range plug? Are you spraying it? If so, I wouldn't use a colder range *Platinum* anyway, and only a 100 shot would require a one step colder, a 60 shot would be fine with the stock range, albeit I would prefer a copper in that scenario, too.
Everybody here warned me about even the use of the NGK Iridiums in a stock app, stock heat range, which I now have sitting on the shelf.
Yes, you can check the resistance of the coil pack with an ohm meter, I'd have to check the fsm to give you the acceptable range of resistance, but if the car ran miss-less before you changed the plugs, I would check all connections relative to changing the plugs. (whatever you had to remove to gain access to them.
Everybody here warned me about even the use of the NGK Iridiums in a stock app, stock heat range, which I now have sitting on the shelf.
Yes, you can check the resistance of the coil pack with an ohm meter, I'd have to check the fsm to give you the acceptable range of resistance, but if the car ran miss-less before you changed the plugs, I would check all connections relative to changing the plugs. (whatever you had to remove to gain access to them.
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Q45tech
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Unfortunately just because the primary resistance reads ok and the secondary seems good doesn't mean that the insulation is not breaking down.
Old Q 90-93 rarely had problems but the redesign in 94 and 97 became more problem prone. Usually happened right after a 60k plug change - internal damage from pulling too hard. Much like what happens on I30/I35.
Any $200 OBD2 scanner will tell you which plugs are misfiring!
Old Q 90-93 rarely had problems but the redesign in 94 and 97 became more problem prone. Usually happened right after a 60k plug change - internal damage from pulling too hard. Much like what happens on I30/I35.
Any $200 OBD2 scanner will tell you which plugs are misfiring!
I am back to square one again. I thought I fixed the problem, but after a couple more test drives, it happened again. I noticed that it happens if I drive more than 15 minutes. Once it happens, it occurs more often if I keep on driving. It looks like when the engine is hot it does that.
I went out and brought a OBD II scanner. The scaner reported everything passed. Even the spark plugs misfire.
I think I will have put back my old spark plugs now.
Any suggestions?
I went out and brought a OBD II scanner. The scaner reported everything passed. Even the spark plugs misfire.
I think I will have put back my old spark plugs now.
Any suggestions?
"Even the spark plugs misfire." Which ones? All or just 1 or 2? Swap the coils (not plugs) on the ones that are misfiring with good ones. I suspect the coil(s) because of the inconsistency and randomness under the conditions. Handling the coils seems to shift things around just enough to get them to work for a while, then the problem comes back. Just my observations when I had the same symptoms earlier this year. Any visual differences from one plug to the next when you took them out? Any carbon buildup on the top half of the plug or on any of the coils?
I am sorry for not making it clear about the spark plugs misfire. The scanner reports everything passed, and no misfire at all.
It is kinda weird that the problem seems like a spark plugs misfire, but the scanner reports there is no misfire.
When I took out the spark plugs to reinstall them again, three of the spark plugs had some brown oil at the spark plugs thread. The oil is not much, but I can see them. None of the plugs have any carbon build up at the top half or at the coils.
It is kinda weird that the problem seems like a spark plugs misfire, but the scanner reports there is no misfire.
When I took out the spark plugs to reinstall them again, three of the spark plugs had some brown oil at the spark plugs thread. The oil is not much, but I can see them. None of the plugs have any carbon build up at the top half or at the coils.
I wouldn't buy a new coilpack just yet. Can you disconnect one coilpack at a time until you figure out which disconnect doesn't make a difference in the idle? If you can narrow down which cylinder it is, then swap its coil with one from another cylinder, and then repeat to see if the miss moves with the coilpack or not.
The oil is probably from a leaking valve cover gasket--they'll need to be resealed. Sometimes the oil leaks down the plug threads, but you would probably be able to tell by the looks of the bottom end of the plugs if this was a problem.
The oil is probably from a leaking valve cover gasket--they'll need to be resealed. Sometimes the oil leaks down the plug threads, but you would probably be able to tell by the looks of the bottom end of the plugs if this was a problem.
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HeavyDuty
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"Spraying" meant nitrous oxide, nevermind. 
No reason to use a colder plug in a stock application.
The "5's" are stock heat range whether it's a SR20, VH45, or VG3XDE(TT) [in NGK nomenclature]
The oil on the plug threads indicates oil was seeping past the plug well o-rings in the valve cover.
If one of the coil packs' resistance is higher than the others, it may mave been damaged in removal/installation.
I *still* would look for a slight crack in the porcelain part of the plugs, (on my way to the parts store to obtain the correct plug.)
Edit: Amen! to what Daedalus said.
No reason to use a colder plug in a stock application.
The "5's" are stock heat range whether it's a SR20, VH45, or VG3XDE(TT) [in NGK nomenclature]
The oil on the plug threads indicates oil was seeping past the plug well o-rings in the valve cover.
If one of the coil packs' resistance is higher than the others, it may mave been damaged in removal/installation.
I *still* would look for a slight crack in the porcelain part of the plugs, (on my way to the parts store to obtain the correct plug.)
Edit: Amen! to what Daedalus said.
I can't believe it. I put back the old spark plugs and it runs like a champ. I drove my wife to three stores and drop her off. At each one of the store, I drove around the parking lot and listened to see if I still have that problem. No problem at all. I must have been driving around for like 2 hours.
My conclusions are either one or more spark plugs are messed up or I am using the wrong type of the spark plugs. My old spark plugs were the "standard" type. The new spark plugs were the "cold" type.
What do you guys think?
My conclusions are either one or more spark plugs are messed up or I am using the wrong type of the spark plugs. My old spark plugs were the "standard" type. The new spark plugs were the "cold" type.
What do you guys think?
Thanks for the reply Tgvince.
I did not check the gaps of those plugs because they are supposedly pre-gapped by the manufacture. Also, since those are platinum plugs, measuring them might strip away the platinum tip.
I did visually compare them with the old plugs and they looked the same.
It is impossible for the gap to mess up during shipment because each one of the plugs has the protective cover.
BTW, I talked to Joe at Scottsdale, he was extremerly nice. He is going to exchange those plugs to the standard type. I will try to install them once I get it.
I did not check the gaps of those plugs because they are supposedly pre-gapped by the manufacture. Also, since those are platinum plugs, measuring them might strip away the platinum tip.
I did visually compare them with the old plugs and they looked the same.
It is impossible for the gap to mess up during shipment because each one of the plugs has the protective cover.
BTW, I talked to Joe at Scottsdale, he was extremerly nice. He is going to exchange those plugs to the standard type. I will try to install them once I get it.
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Tgvince
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You can check the gap on Plats...your just not supposed to have to re-gap them. I used NGK plats that were not boxed by Nissan so i suppose that the Nissan ones come gapped for the application. I wouldnt trust it however:). Also those cheesy little gapping/key ring tools that you get from the autoparts store can be off as much as a couple thousandths...which is alot when gapping plugs:).
Terry
Terry