SPark Plugs - Should I worry?

[anonymous1]

Hi,

I removed my spark plugs yesterday to complete a compression test (which seemed to come back OK - all cylinders read around the 200 mark) and they seem to be quite badly soiled. Especially considering I only changed them approx 2 months ago.

http://img28.picoodle.com/img/img28/4/5/25/f_DSC00147m_a1ed39f.jpg (http://www.picoodle.com/view.php?img=/4/5/25/f_DSC00147m_a1ed39f.jpg&srv=img28)

The least affected one seemed to come from #6, but there appeared to be oil residue on all of them. I haven't noticed any blue smoke on start up or during normal running, although I do seem to be losing oil, but looking underneath this is via a minor leak rather than burning.

Just wondering if it's something I should worry about or if it's simply a case that I may need to change the plugs slightly more often and keep an eye on the oil. I was thinking it might be similar to bobchiba problem on another thread, which general consensus is not to worry, but they have smoke from the exhaust. Only thing I have noticed on my exhuast is that I had the back box it changed about 8 months and there is black, sooty looking residue on it?

Cheers in advance for all advice.

[Jon K]

i mean you might have a little oil burning but its relatively normal - they don't look bad. Instead of months, how many miles are on them and do you drive the care and shut it down often in shortish trips?

Instead of those plugs, try NGK BKR6E I think they'll hold up better.

[anonymous1]

i mean you might have a little oil burning but its relatively normal - they don't look bad. Instead of months, how many miles are on them and do you drive the care and shut it down often in shortish trips?

Instead of those plugs, try NGK BKR6E I think they'll hold up better.

Hi,

Cheers for the quick response, put my mind at ease.

I probably have only put about 600 miles on them, most of the driving I do is shortish trips (around 6-7 miles) which I suppose is more wearing in general.

I'll change over to the plugs you suggest next time I swap them out... Do you know what gap will be needed on these ones or can I get them pre-gapped?

Thanks

[whiskychaser]

Hi,

Cheers for the quick response, put my mind at ease.

I probably have only put about 600 miles on them, most of the driving I do is shortish trips (around 6-7 miles) which I suppose is more wearing in general.

I'll change over to the plugs you suggest next time I swap them out... Do you know what gap will be needed on these ones or can I get them pre-gapped?

Thanks
The short trips are probably the cause of the soot-its running rich until its warmed up properly. If you pull them again after a couple of hundred miles of motorway driving they will look quite different. You seem to have a tad of oil on 1 and 5 but I'd agree there's absolutely no cause for concern.

[Morgenster]

i mean you might have a little oil burning but its relatively normal - they don't look bad. Instead of months, how many miles are on them and do you drive the care and shut it down often in shortish trips?

Instead of those plugs, try NGK BKR6E I think they'll hold up better.

I concur. Wonderful alternative

Also maybe check PCV system for blockages?

[Tiger]

I am worried... even with my oil burner, it didn't foul up my plug like that. You need to run an electronic diagnostic test to make sure everything is running at spec...

It could be bad MAF... are you sure you don't have any other running problems?

[filip00]

i think those look ok. last plugs i had were beru and lasted merely 15k miles. now i've put in bosch and the idle seems smoother.

[anonymous1]

Hi,

Thanks for the replies, they have put my mind at ease over the plugs and I will try the alternatives mentioned when I change next. Think I'll also start taking it out for a blast down the motorway more often to try and compensate for the short trips. (Although with the current fuel prices it's an expensive form of compensation.)

Tiger - I have had another issue with a backfire/misfire, detailed in this thread http://www.bimmernut.com/forum/showthread.php?t=38264. But to be honest I haven't had it for a while now, since replacing the charcoal canister, along with the vent pipe going from this to the tank and also cleaning the valve with carb cleaner. Not sure if this is due to me subconsciously avoiding the rev range or it just having finally decided to give me a break though. ;) I did consider at one point the MAF could be causing some issues, but with the prob disappearing and me not having a clue where to start for doing a check on the MAF I haven't done one... Not tried any electrical checks on the vehicle as yet.

Cheers again.

[SnakeyesTx]

How are your o2 sensors? Seems a little excessively rich for such few miles.

Maybe a seafoam bottle in the tank and a MAF cleaning could be in order as well :D

[anonymous1]

How are your o2 sensors? Seems a little excessively rich for such few miles.

Maybe a seafoam bottle in the tank and a MAF cleaning could be in order as well :D

Hi,

Thanks on the advice.

I'm not sure on the o2 sensor locations, is it just the one before the cat or should there be another one? How would I check this... does it require a volt meter?

I didn't know I could clean the MAF - can this be done just spraying it with carb cleaner on the thin wires behind the mesh? I'll have to look into the seafoam, don't think I've seen it available over the counter in the UK.

On another note, which I'm wondering if could relate to this, my car tends to idle at about 500RPM. Would this be considered as normal or is my mixture wrong? It idles smoothly, just seems quite low is all.

Cheers

[SnakeyesTx]

I'd imagine that you have just 1 O2 sensor, even my 95 525 had just one in front of the cat since it was OBD-1. As for MAF cleaning, there's 3M Throttle body and Intake cleaner which tends to work well, and I've even seen Berryman Mass Air Flow cleaner (both are sprays). My friend bought the Berryman one and basically you just take the MAF out of the car, spray it thoroughly on one side, let the remaining liquid drain out the other side, then spray the back side and let it drain out the front and let it dry completely before reinstalling.

As for your idle, I see your's is a manual, like my E39 is. My V8 idle's at 500 rpm as well and there's no ping and is smooth as silk.