Little off since sparkplug change

[ulrichd]

Changed my sparkplugs over the weekend. No issues, no codes , car runs fine. I do notice an ever so slight dip in idle speed (at about 700) and ever so slight increase in idle NVH (less refinement). It's very subtle.

I went with Bosch plugs from BavAuto but noticed the OEM plugs are NKG.
If I have time I might put the old plugs back in just to see. Would the Bosch plugs be the problem?

[pj.rodriguez]

Don't know if this has been spoken about in the past, but I remember reading somewhere that you should definitely only replace with the OE plugs from your BMW parts dealer. There have been some stories about plugs not working properly even though they are Bosch

[MZWIE]

No no....no issue with non dealer plugs. I've used them and have had no issues. The whole story is somewhat apochryphal.

[Billup]

I'm currently running the same Bosch plugs from BavAuto with no issues.

The stories of them not working as well or similarly may be a hit or miss type scenario. People will always tell you to go with OEM only, but even OE style parts are generally held to to the same tolerances and manufacturing standards as an OEM part.

Now if you tried Chinese plugs, that would raise suspicion.

[Chris.]

Lower idle will cause more resonance. As long as you aren't noticing any misses I wouldn't worry about it.

Did you mess with the gapping at all?

[Freon]

Idle varies when you do nothing at all. I think you may to a certain extent be acting in a more observant way because you just changed parts. Also the new plugs may take some time for the ECU to relearn (hate to speculate how long, but give it 100-200 miles maybe?). The important part is lack of misfire or hesitation.

[ulrichd]

Seems to have evened out. Thanks guys.

[WP1]

Please post how to change the sparkplugs

Bought mine 135i with 34K miles last year. Everything is well now, but wanted to know for future. I used to change them with my old car.

[ShocknAwe]

Originally Posted by WP1

Please post how to change the sparkplugs

Bought mine 135i with 34K miles last year. Everything is well now, but wanted to know for future. I used to change them with my old car.

http://www.1addicts.com/forums/showthread.php?t=602804

[TheSt|G]

Originally Posted by Billup

I'm currently running the same Bosch plugs from BavAuto with no issues.

The stories of them not working as well or similarly may be a hit or miss type scenario. People will always tell you to go with OEM only, but even OE style parts are generally held to to the same tolerances and manufacturing standards as an OEM part.

Now if you tried Chinese plugs, that would raise suspicion.

No, they aren't. Which is why they are called OEM. OE is tested and certified by the manufacturer. OEM is not.

[Billup]

Originally Posted by TheSt|G

No, they aren't. Which is why they are called OEM. OE is tested and certified by the manufacturer. OEM is not.

Genuine / OE - Genuine or (OE) Original Equipment is basically the original part used by the car manufacturer on the car when it left the factory. That part could have been made under contract by an OEM supplier, like Bosch, Mann, Hella or other OEM supplier, for instillation on the new car. There are many parts like body panels, brake rotors, interior trim items, etc. that are made in the car manufacturer's own factories, or sometimes factories under contract to produce that product only for the car manufacturer. Many use the term OE interchangeably with the term Genuine. An OE part and a Genuine part will both come in the original car manufacturers packaging, such as Mercedes, BMW, Porsche or whatever the original car brand. An example of a Genuine Porsche part is 996-803-183-09 seat belt lock. You can rest assured that any part labeled "GENUINE" refers to a part supplied by a supplier that is the OE part in the vehicle manufacturers packaging. The Genuine part and OE part are equivalent, as described above. Sometimes the OE or Genuine part comes from the OE supplier, like Mercedes, in a multiple unit package, and therefore may not be shipped in that package.

OEM - Original Equipment Manufacturer refers to a part that is manufactured by a company like Bosch, Mann, Hella and others under design from the car manufacturer, like Audi, VW, etc. This part is then made available for sale by the OEM manufacturer, but in that manufacturers packaging. In many instances the car manufacturer's part number and logo are removed to prevent copyright infringement. The bottom line here is that the OEM part is the same part as was installed originally (OE) and is equivalent. Many times I will use the term OEM equivalent and this refers to a part that meets the same quality standards as the OEM part. Sometimes what was used as OE on the new car may no longer be the OEM, a good case is Bremi and Bosch ignition products for BMW. I told you it was confusing! An example of an OEM part is this Mercedes heater blower motor 211-830-09-08.

I quote this because I designed OEM parts for Denso and Bosch when I resided in Michigan. I now design OE parts for GM, Ford, Mercedes, and Ferrari here in NC. OEM parts under go the same testing, as with any company (including food), products are tested for longevity, accuracy, and consistency. The only thing certified by the actual manufacturer is the test report logs from the supplier. The vehicle as a whole is tested for all the components in congruence with each other.

Which is why a Bosch plug in a Mercedes Box is the same this as a Bosh plug in a Bosch box. Part numbers are cross referenced, and are then labeled brand specific for the purpose of Mercedes inventory stocking and mark ups.

The things people should be leery about are "aftermarket" branded parts, which is the less expensive China or Mexican made, which are not tested or held to the same standards as OE or OEM.

[TheSt|G]

Originally Posted by Billup

I quote this because I designed OEM parts for Denso and Bosch when I resided in Michigan. I now design OE parts for GM, Ford, Mercedes, and Ferrari here in NC. OEM parts under go the same testing, as with any company (including food), products are tested for longevity, accuracy, and consistency. The only thing certified by the actual manufacturer is the test report logs from the supplier. The vehicle as a whole is tested for all the components in congruence with each other.

Which is why a Bosch plug in a Mercedes Box is the same this as a Bosh plug in a Bosch box. Part numbers are cross referenced, and are then labeled brand specific for the purpose of Mercedes inventory stocking and mark ups.

The things people should be leery about are "aftermarket" branded parts, which is the less expensive China or Mexican made, which are not tested or held to the same standards as OE or OEM.

This may be the case for your individual company, but those who have been working on the cars long enough knows that it is not generally the case. Look at the spark plug thread, they OE and OEM Bosch plugs aren't even visually similar, let alone in function.

There is a reason a lot of indy shops refuse to work with OEM parts, as they don't want to be blamed for component error later.

Mike Miller also reccomends against OEM parts vs OE in mosts instances, like the afforementioned spark plugs:

Original BMW Bosch Spark Plugs vs. Aftermarket Bosch Spark Plugs

Like just about everything else on the modern BMWs, Bosch spark plug choice is complicated and confusing. The short answer is if you order the spark plugs from BMW (sometimes there is a choice between Bosch or NGK), then you are good to go and there is no confusion. But they are expensive.

Savvy enthusiasts have found that Bosch has a part number for commercially-available spark plugs that cross-references to the BMW original equipment Bosch spark plugs, often at a fraction of the price. The problem is, the commercially-available (aftermarket) Bosch spark plugs are not always the same as the original BMW Bosch plugs even though they cross-reference and they do work.

Dealership technicians report problems with the commercially-available Bosch Platinum +4 spark plugs in BMW engines. I have never seen this personally, but physical inspection does reveal differences in insulator design between the original BMW Bosch spark plugs for the modern cars and the commercially-available Bosch Platinum +4.