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I did an 'inspection 2' this weekend, which involved changing the plugs. I have a question about 'reading' the old plugs, it's been a while since i've changed plugs.

The old plugs had 56,900 miles on them (i was on my last green light before insp2) and came out with a brownish color to the porcelin. More of a chocolate/mocha color than the lightish tan i've seen in past modern cars. I don't baby the car, and generally use only chevron premium (only 91 octane here in ca.) so i was surprised how dark they look. To those who have changed their own plugs, does this sound normal?

The comment: the car runs quite a bit smoother, and feels stronger with the new plugs. I certainly won't go another 60k before I change them, 30k sounds like a better interval.
Thanks,
Mike
 

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Sounds like you got some of that lost spring back in the step...

Im not an expert on reading plugs and i havent seen the "normal" m5 plug yet, so ill step out of that portion of the post.

I think the 30K interval is a good one...
 

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Mike,

I am assumming Inspection 2 always involves changing the plugs? I too am coming upon that inspection. What plugs did you use as replacements for the OEM plugs?

Good to hear that you have a renewed vigor in your car. I am a little surprised that the plugs needed changing at this level of mileage. I thought there were a number of plugs good for 100,000 miles.

Mark
 

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Discussion Starter #4
Yes, spark plugs are part of the inspection 2 for M cars, at least according to my 00 service booklet. I got the parts from the dealer, cost for what i needed was about $120 (i had some oil on hand, so that's not included) which sure beats $850. I still have a couple of things to check under the list of "inspections" but i'll have my wheels off next weekend to get my track tires mounted (need to scrub them in before sears point) so i'll look at the brake pads etc then. Factory plugs are NGK, cost was about $8/plug with a pretty decent discount. (i'll have to check on that to be sure).
Mike
 

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mottati said:
I did an 'inspection 2' this weekend, which involved changing the plugs. I have a question about 'reading' the old plugs, it's been a while since i've changed plugs.

The old plugs had 56,900 miles on them (i was on my last green light before insp2) and came out with a brownish color to the porcelin. More of a chocolate/mocha color than the lightish tan i've seen in past modern cars. I don't baby the car, and generally use only chevron premium (only 91 octane here in ca.) so i was surprised how dark they look. To those who have changed their own plugs, does this sound normal?

The comment: the car runs quite a bit smoother, and feels stronger with the new plugs. I certainly won't go another 60k before I change them, 30k sounds like a better interval.
Thanks,
Mike
Mike, I changed mine at 34K. One was changed under warranty (they believed that it was the reason that cylinder (#4)) misfired. I then had them change the other 7.

If possible, post pics of yours and I'll post mine and we can compare.

Jeff cherrsagai
 

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Mike, good to hear ur inspection 2 came out good... I'll be needing the inspection 2 soon too... I might ask you for a couple pointers so I can do it my self.....
 

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Changed mine at about the same mileage. Although I could see wear, frankly, I think they would have gone another 15-20K easily. Mine were a little lighter than you decscribe - sort of mocha foam color - which is exactly what I wanted to see. As important is evenness from cylinder to cylinder. The color of your plugs might be explained by a number of recent starts without full warmup, or running a tad rich - though problematic rich will be black. Can you post a good, well-lit, close-up photo?
 

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I recently changed plugs also and notice a marked improvement in the cars running, in particular its much less inclined to misfire resulting in the dreaded limp-home-mode (which I had previously attributed to dodgy cam sensors). One of the plugs was very black, so it or the coil could have been at fault.

The car runs very rich at startup from cold (black smoke) until it warms up and sounds quite noisy, but I'm assuming this is normal?
 

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Úbermensch said:
One of the plugs was very black, so it or the coil could have been at fault.

The car runs very rich at startup from cold (black smoke) until it warms up and sounds quite noisy, but I'm assuming this is normal?
Not normal. Normal cold noise is from Vanos rattle ONLY until oil pressure builds - a few seconds. After that it should purr - and mine never smokes at startup. The lone black plug is indeed a cause for concern - bad coil, bad injector, bad or misadjusted throttle actuator/butterfly, loose or bad plug, worn valve.... lots os possible explanations. Hope for the simple/cheap (bad plug!)
 

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I don't mean REAL loud, like rattly or anything, more like a leaky exhaust kind of aggressive note, and the noise\smoke disappears once the engine warms up (ie. when all those dash lights have disappeared),.

I might run one of those injector cleaner petrol additives and maybe clean the MAF meters, hell I like all those explanations except the 'worn valve' one
 

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Discussion Starter #11 (Edited)
greg said:
Changed mine at about the same mileage. Although I could see wear, frankly, I think they would have gone another 15-20K easily. Mine were a little lighter than you decscribe - sort of mocha foam color - which is exactly what I wanted to see. As important is evenness from cylinder to cylinder. The color of your plugs might be explained by a number of recent starts without full warmup, or running a tad rich - though problematic rich will be black. Can you post a good, well-lit, close-up photo?
The day before I had a sprited run up to 7k+ with a fellow board member, testing out some of his new parts, but the day i changed the plugs, i did have a <1mi drive to and from my office, with a little putting around town thrown in. All 8 look very similar, which i was happy to see. here are a couple of pics. the color does sound like what you describe.
I paid $7.19 per plug, by the way (someone had asked earlier).
Mike
 

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This is what the spark plugs will look like now that the fuel blend in Calif is going to have a ethanol blend.
I have to read plugs most every weekend. I freaked when I first saw the rusty brown color. I thought we had blown a head gasket and was in for a longer night of repairs(or engine change).

I look for a lite brown at the tip, lightening to a tan on the ceramic.
Three to four threads should show heat discoloring.
 

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Here are pics of plugs removed from my car at 35,000 miles. Cylinder 5 is missing because that plug was changed under warranty (fouled). The SA sent the plug back to BMW before I could get a pic of it.

Pics are named"Cylinder 1", "Cylinder 2", etc...move your cursor over the pic to see which is which.

Any comments or impressions?

Jeff cherrsagai
 

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Discussion Starter #15
RennSportSC'dKellenersM5 said:
Did anyone change out to Iridium plugs? Just wondering...

Also are bosch +4 plugs standard issue for m5's?
I thought about it, but didn't find much with a search that it's really worth much, and i did hear of the potential that the electrode could break off!?

the factory plugs, and the replacements i got from bmw were identical NGK's with the 4 prongs.
Mike
 

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Discussion Starter #16
x703jko said:
Here are pics of plugs removed from my car at 35,000 miles. Cylinder 5 is missing because that plug was changed under warranty (fouled). The SA sent the plug back to BMW before I could get a pic of it.

Pics are named"Cylinder 1", "Cylinder 2", etc...move your cursor over the pic to see which is which.

Any comments or impressions?

Jeff cherrsagai
Jeff, your plugs look normal to me. Mine look a little more "brown" but i think i'll attribute that to differences in our fuels, with our crappy 91 octane, oxygenated fuels, vs your 93-94 octane stuff.
Mike
 

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mottati said:
I thought about it, but didn't find much with a search that it's really worth much, and i did hear of the potential that the electrode could break off!?

the factory plugs, and the replacements i got from bmw were identical NGK's with the 4 prongs.
Mike
Hmm...

interesting..i know that the iridium plugs show little gain in power under NA applications for the most part but i find it hard to believe about a electrode braking off. That could happen with most any of them im sure.

Interesting that a german company uses asian spark plugs....do we want to read into that at all? Bosch isnt used (euro) but NGK (asian) is?
 

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RennSportSC'dKellenersM5 said:
Hmm...

interesting..i know that the iridium plugs show little gain in power under NA applications for the most part but i find it hard to believe about a electrode braking off. That could happen with most any of them im sure.

Interesting that a german company uses asian spark plugs....do we want to read into that at all? Bosch isnt used (euro) but NGK (asian) is?
I do not believe that it is any surprise at all that we see NGK instead of Bosch. I still firmly believe the Japanese do a better job at the electronics than the Germans.

Mark
 

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RennSportSC'dKellenersM5 said:
but i find it hard to believe about a electrode braking off.
Interestingly enough, my SA said that broken common electrodes with these plugs is not unheard of. In the same sentence he also told me that I shouldn't be concerned.

I'm thinking of changing to Iridium plugs and possibly plasma coils.

Jeff :cheers:
 
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