spark plugs covered in oil!!

Level 1 User Joined: 22 Jun 2006 Posts: 31

As title...been having some running problems with my 19 16v, in that at high revs(excelleration) i apparently get blue smoke. Also, at idle it will only idle at 2500rpm!!

Now, i remover the plugs, and both no's 1 and 2 were covered in oil...not just on the electrodes, but also where the HT lead meets the plug!!

Would this have any link to blue smoke and idle speed, and why are there covered in oil!!

Cheers all!!

Matt

Site Subscriber Joined: 07 Oct 2004 Posts: 2281

Blue smoke is excess fuel.

Oily spark plugs probably caused by a blown rocker cover gasket.

Level 1 User Joined: 22 Jun 2006 Posts: 31

is blue smoke not burning oil??

Blown rocker gasket?!! That'd be a result!! lol What are signs of knackered piston rings and oil stem seals??

Site Subscriber Joined: 07 Oct 2004 Posts: 2281

Nah black smoke is burning oil, pretty sure it is anyway!

Just done a quick bit of research, worn piston rings would manifest themselves by giving poor compression, burning oil, and loss of fuel economy due to unburnt fuel being dumped into the crankcase - all pretty logical deductions tbh.

A few articles do suggest that oil fouling of the spark plugs is another sign, so you might well be right.

Not sure about the valve stem oil seals, but if they're leaking excess oil into the combustion chamber then they'd foul your plugs - but not externally as I'm inferring from your original post.

In either case you'd be burning black smoke not blue, ask someone to tell you what colour it is as judging by what it looks like in your rear view mirror isn't gonna be the most reliable way of telling.

Site Subscriber Joined: 07 Oct 2004 Posts: 2281

I'd still say it's the rocker cover gasket though! It's the only way oil can feasibly reach the places you're finding it!

As regards you're idling/blue smoke issue I'm gonna plump for the easy diagnosis and say it's a duff sensor somewhere - maybe lambda but I'm just hazarding a guess! Perhaps throttle position sensor as well?

Level 1 User Joined: 22 Jun 2006 Posts: 31

my mate said it was blue, and he was driving behind me!!

So we can rule out piston rings then i think?!! :?

""Not sure about the valve stem oil seals, but if they're leaking excess oil into the combustion chamber then they'd foul your plugs - but not externally as I'm inferring from your original post"" - don't understand this?!! lol

Site Subscriber Joined: 07 Oct 2004 Posts: 2281

If you pull the HT leads off the plugs in the engine bay can you see oil?

Retroholic Joined: 23 Dec 2005 Posts: 3315

1st oil is rocker cover i had same a month ago changed it job done!

check that the idle screw is wound all the way down on the TB its at the top in a round thing

Level 1 User Joined: 22 Jun 2006 Posts: 31

bbracer16valver";p="102612 wrote:

1st oil is rocker cover i had same a month ago changed it job done!

check that the idle screw is wound all the way down on the TB its at the top in a round thing

Oil is fine on both points!!

Level 1 User Joined: 22 Jun 2006 Posts: 31

Gentle Ben";p="102611 wrote:

If you pull the HT leads off the plugs in the engine bay can you see oil?

Haven't really looked, but becuase they were covered in oil, i'm gonna say yes!!

Site Subscriber Joined: 07 Oct 2004 Posts: 2281

Well what I'm trying to establish is whether the oil is finding it's way outside of the engine, which seems to be the case if you're finding oil "where the HT lead meets the plug".

A rocker cover gasket failure is the only way oil can leak down into the plug wells and onto the plug/HT leads. Oil can't get there from anywhere else, certainly not from worn stem seals/piston rings.

Level 1 User Joined: 22 Jun 2006 Posts: 31

thanks ben!! it does sound to be a logical answer to oil getting to where the ht lead meets the plug!!

As for oil on the elecrodes of the plug??!! (hopefully from just removing them out of the engine!! lol)

Site Subscriber Joined: 07 Oct 2004 Posts: 2281

If there's a fair bit of oil matey it will leak down the threads on to the electrodes as you unscrew the plug.

Alternatively if you've got a Haynes manual you could look on the inside back cover and compare your plugs with the ones illustrated - that should give you an indication as to whether there's anything more seriously wrong.

But for now I would change the gasket, renew your plugs and leads and see if it improves.

If the screw on the TB is wound down then I'm going with sensor issue like I did before, my knowledge on fuelling/injection isn't the best but I do know that the ECU reads from the lambda and throttle position sensors to calculate air:fuel ratios etc. so there's a start!

Level 1 User Joined: 22 Jun 2006 Posts: 31

cool, well i'll deffo look at the rocker gasket. As for sensors...both lamba and throttle spd have been replaced!!

Even if i have oil over the plugs, will this aaffect idel speed??

Cheers for all ur hlpe so far!! :)

Site Subscriber Joined: 07 Oct 2004 Posts: 2281

No prob, it's what we're here for.

Oil on the plugs is not really beneficial, if the electrodes are covered in oil and blocking the spark from seeing all of the air/fuel in the cylinder then I'd expect it to run fairly lumpy, I certainly wouldn't expect the revs to rise though, but that's just my opinion of course.

One way you may be able to diagnose if one of those sensors is at fault is by unplugging them and seeing if there's any change.

Now.... whether it's safe or recommended to unplug these sensors on a running engine I don't know, but I do know you can unplug the coolant temperature sensor as a temporary measure to alleviate cold starting problems so it maybe possible, then again maybe not so I'd wait for someone like Chris to give a second opinion...

...although knowing Chris he'll diagnose it as something completely different!

Level 1 User Joined: 22 Jun 2006 Posts: 31

lol, cool!! Always the way. well hopefully chris will read this soon and shed some more light on it!! Loking forward to tomorrow now to have a go at it!! lol

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

can't be arsed to read it asll

blue smoke is burning oil, they all do it to some extent.

oil on the plugs is dodgy cam cover gasket.

Retroholic Joined: 23 Dec 2005 Posts: 3315

Level 1 User Joined: 22 Jun 2006 Posts: 31

well, i've still had no luck!! the rocker cover gasket seems to be fine!! i din't go as far as the gasket between the actually head and the rocker(if that makes sense)

So, moving on from this, it filaed its MOT today on emissons at low idle!! Any ideas to as why??

Ta!!

Level 4 User Joined: 03 Jun 2006 Posts: 83

What does it say on the exhaust gas analysis sheet?

Level 1 User Joined: 22 Jun 2006 Posts: 31

which part of it excaclty??

says that idle speed failed. Natural idel speed CO = 7.19%