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06-13-2016, 09:21 PM | #1 |
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Backfiring badly :(
Anyone know what might be causing this?
I switched to NGK plugs (gapped by Justin). And it is backfiring quite bad. Very loud bang, smoke all over the road, etc. I am running e70, with Jb4 BEF for e85, kitty dps, stage2 lpfp. Anyone have any ideas what could be causing this? Super embarrassing and I don't have the confidence to put my foot down now. Any ideas or suggestions? I have a log of when it happened too. |
06-13-2016, 09:34 PM | #2 |
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Drives: N54 135i 6MT
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Any logs? Mistaking it for misfiring?
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06-13-2016, 09:36 PM | #3 |
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still got the old plugs? assuming they are oem and work chuck them back in see how you go for the 20mins or so it takes to do you've eliminated one variable. even better probably a good idea to check for codes first. CEL?
backfires are fuel burning in places it shouldn't be i.e. intake or exhaust. if you havnt got PI it's doubtful it's in the intake could be a leaking injector spitting fuel into the exaust..... have they been changed before? |
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06-13-2016, 10:26 PM | #4 |
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Yep i've got logs. It isn't a misfire and there are no CEL or codes.
It's definitely a backfire as there is a loud BANG then i look back on the road and there is a HUGE plume of smoke. It only happened after changing my plugs. I changed my oil too but that's pretty straight forward. It's happened 2-3 times now. Same circumstance, 2nd gear and putting foot down. Here is the log. http://datazap.me/u/dh58/back-fire-log Yes the injectors have been replaced but they are being a little bit squeeky on startup now. (only started happening in the cold) |
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06-14-2016, 02:43 AM | #5 |
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Your logs say you're running meth, is that true?
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06-14-2016, 02:47 AM | #7 |
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Am I going crazy?? Haha
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06-14-2016, 02:59 AM | #9 | |
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+1 try your old plugs in and see what happens. Seems weird!
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06-14-2016, 02:59 AM | #10 |
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06-14-2016, 04:57 AM | #12 |
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So... you changed your plugs bc of a rough idle... but now your engine back fires badly.
Humm... maybe it is your plugs? Try factory plugs bought from a BMW dealer. I've been saying for years that our cars are very sensitive to plugs.
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06-14-2016, 05:00 AM | #13 | |
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Quote:
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06-14-2016, 05:37 AM | #14 |
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Regap your plugs, you said you bought them pregapped?
The NGKs you have to bend the ground tab a LOT to get it to 0.022" because the gap is so wide. After its been bent that much it doesnt take much force at all for the gap to open up and be out of spec. Pull the plugs, check the gaps. Careful with the electrode because it is very brittle and can be damaged easily.
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06-15-2016, 01:13 AM | #15 |
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Do you have NLS setup by any chance?
When I turn NLS on in my car (Procede) the backfires are beyond loud. I fucks up rev match downshifting though so you can't run it on the circuit, only really for the drags.
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06-15-2016, 01:48 AM | #16 |
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Thanks guys.. I pushed her hard today in the same circumstances as before with no issues. I can't check out the plugs until the weekend.
I don't have NLS. I got the plugs pregapped by Justin at Advan so I'm pretty confident that they are good. However I will be taking them all back out to check. |
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06-17-2016, 06:48 AM | #17 |
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Very weird... the first 2 days after the change, backfires were easy occurrences.. I have tried everything in my will to make it happen again over the past few days and nothing..
So could this be due to anything during the change of the spark plug? And not the spark plug them selves.. ? |
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06-17-2016, 10:41 PM | #18 |
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Did you notice anything falling past the plugs when you removed them? something may have been burning off?
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06-18-2016, 06:48 AM | #19 |
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