335i Sedan spark plugs help..

[WickedB]

I have a 2007 335i with almost 70,000 miles. I think I need to replace the spark plugs, I get some misfires at idle when it is warming up...and it probably hasn't been done yet :confused (I just got the car 2 mos ago).

I've read these cars are pretty picky on spark plug brand/model.... What is the most recent plug part #? And where can I get it from cheapest? (although I will pay more for 'better', if there's options). I also understand I need a specific spark plug socket... where can I get this from? Ideally for less than the $47 I saw it for online somewhere...:D

Thanks for your help. :redspot

[ronnyb29]

I would get OEM plugs from the dealer and here is the tool you need. Bosch are the only other plugs you should consider using.

http://www.burgertuning.com/N54_BMW_spark_plug_socket_adapter.html

[ECSTuning]

The genuine BMW or Bosch plugs are what you should be looking for, HERE (http://www.ecstuning.com/BMW-E92-335i-N54_3.0l/Engine/Ignition/?salesrep=JRiggsbee&utm_source=bimmerforums&utm_medium=forum&utm_content=JRiggsbee&utm_campaign=postreply) is a link to my selection of plugs for your 335.

As for the tool I highly suggest the Schwaben Deep Well Spark Plug Socket - 3/8" Drive found HERE (http://www.ecstuning.com/Search/ES1306821/ES1306821/?salesrep=JRiggsbee&utm_source=bimmerforums&utm_medium=forum&utm_content=JRiggsbee&utm_campaign=postreply). Schwaben designed it specifically for the N54 and N55.

http://c1552172.r72.cf0.rackcdn.com/123658_x300.jpghttp://c1552172.r72.cf0.rackcdn.com/188446_x300.jpg (http://www.ecstuning.com/Search/ES1306821/ES1306821/?salesrep=JRiggsbee&utm_source=bimmerforums&utm_medium=forum&utm_content=JRiggsbee&utm_campaign=postreply)

[raceyBMW]

I don't recommend that EAS socket, unless its been upgraded, because you have to remove the internal magnet to use it correctly.

I prefer this one (I have used both, and currently have the BMS one).
http://www.burgertuning.com/N54_BMW_spark_plug_socket_adapter.html
edit: oh it looks like someone posted that earlier, yeah, that's the one you want.

Also, cheapest place I have found plugs is on AutohausAZ.com (which I use for all my parts for my 5-series too). They are currently $12.16 a piece (plus you get free shipping on orders over $50 I think), and are the Bosche OEM plugs.

[Cornerspeeed]

Misfires at idle while warming up are almost definitely not spark plugs. Commonly I find a row of bad injectors causing cold start misfires.

You may want to consider additional diagnostics before spending the money on spark plugs, especially because if you are having an injector issue, it's very possible you will destroy those new plugs.

[wtfmarine]

Misfires at idle while warming up are almost definitely not spark plugs. Commonly I find a row of bad injectors causing cold start misfires.

You may want to consider additional diagnostics before spending the money on spark plugs, especially because if you are having an injector issue, it's very possible you will destroy those new plugs.

+1. But when you fix the injectors go to Burger Tuning for replacement spark plugs and special tool.

[WickedB]

Thanks for the replies, how can I further test for an injector problem?

[Cornerspeeed]

Honestly, it's going to be quite tough without diagnostic software of some sort.

You need to narrow down the misfire to the cylinders it is affecting, and then you need to swap injectors on problem cylinders to different cylinders and see if the misfire follows. It's time consuming, and a lot of times it's more then one injector, so if you aren't experienced or very thorough it's quite easy to get confused and chase your tail.

[WickedB]

Honestly, it's going to be quite tough without diagnostic software of some sort.

You need to narrow down the misfire to the cylinders it is affecting, and then you need to swap injectors on problem cylinders to different cylinders and see if the misfire follows. It's time consuming, and a lot of times it's more then one injector, so if you aren't experienced or very thorough it's quite easy to get confused and chase your tail.

Thanks. What causes it to only happen during cold start? Everything seems fine after that... And can I expect it to get worse?

[Cornerspeeed]

Thanks. What causes it to only happen during cold start? Everything seems fine after that... And can I expect it to get worse?

I don't completely understand why they become faulty under cold conditions only.

For some reason, the spray pattern of the affected injectors becomes incorrect, but as far as why, I'm not 100%. The injectors are filled with Piezo crystals, which when electrified, spread and assemble in a very predictable pattern which opens the injector. I would venture to say that it's an issue with the crystal stack settling down during long periods (8 hours from what I've seen), and becoming unpredictable for the first couple hundred injection cycles. Purely speculation. I don't believe it to be an electrical issue inside the injector caused by temperature itself, because I've seen it happen all the same in the middle of summer when conditions are warm even after sitting.

Either way, good luck with getting it fixed. As far as getting worse, I would imagine it will, but I only see and repair the cars as they come through the dealership, I usually don't talk to the customer as far as how long it's been happening, or if it's become worse. An owner here who has experienced the problem first hand will be of more help in that area.

[Loco]

I replaced mine w/OEm & all was well.

[02325]

this motor is direct injected and you can't just swap injectors form one cylinder to another. the injectors are programmed to the DME. evey injector is different. if you look at your injectors they will have a different number. that number is programmed to the DME. they do this cause every injector has a different resistance factor.

hate to be the bearer of bad news on this.

[Cornerspeeed]

Very true, I had failed to mention that. Sometimes having all the necessary software for all repairs makes you forget that others do not.

The dealer/independent with factory software is the only place that will be able to do much with your injector diagnostics if you choose to go that route.

[bimmer_boyis]

Thanks. What causes it to only happen during cold start? Everything seems fine after that... And can I expect it to get worse?

Most of the time it is the injectors leaking. Do you notice smoke from the exhaust on start up? To answer your other question, yes it will get worse and shouldn't be ignored. I've started to see converters needing replacement on earlier cars because the guts are completely rotted out. I can only assume from the amount of raw fuel that runs through them after multiple injector failures.

[325iPhil]

Bosch are the only other plugs you should consider using.

Why? What's wrong with NGK? Best plugs you can buy...