Engine misfiring and oil on spark plug

Wailin

My suzuki jimny has been a bit jumpy starting up on cold mornings recently so I guessed at a dodgy spark plug and went ahead today to change them.

Sure enough, when I removed the ignition coils, one of them was covered in oil. Looking into the spark plug bore I could see more oil covering the spark plug.

I went ahead and changed them anyway and cleaned as much oil as I could. She started up fine with a big belch of blue/black smoke from the oil but cleared quickly and seems to be ok for now.

Whats the most common cause of oil leaking into the spark plug chamber and is it an easy fix or costly?

Irish Steve

If the oil was evident before removing the spark plug, the most likely reason is that the plug was loose in the head, and oil was being blown up the threads, if the new plug went into the thread and tightened OK, for now, drive on, keep an eye on it, and there may be no further issues. There may be deeper issues in play, but for now, keep an eye on the oil levels, and see how it goes.

hi_im_fil

Could also be a rocker cover gasket leaking oil into the spark plug area

Wailin

hi_im_fil wrote: »

Could also be a rocker cover gasket leaking oil into the spark plug area

Hopefully not! Would that affect all plugs if that was the cause and is it a handy DIY fix or expensive mechanic job?

joujoujou

Wailin wrote: »

[...] Would that affect all plugs if that was the cause

It depends. Sometimes would, sometimes not.

Wailin wrote: »

[...] is it a handy DIY fix or expensive mechanic job?

Average DIYer with a bit of knowledge (and basic tools) in most cases will do. Search youtube - you may be lucky and find tutorial video regarding your particular vehicle/engine.

newmember2

Wailin wrote: »

My suzuki jimny has been a bit jumpy starting up on cold mornings recently so I guessed at a dodgy spark plug and went ahead today to change them.

Sure enough, when I removed the ignition coils, one of them was covered in oil. Looking into the spark plug bore I could see more oil covering the spark plug.

I went ahead and changed them anyway and cleaned as much oil as I could. She started up fine with a big belch of blue/black smoke from the oil but cleared quickly and seems to be ok for now.

Whats the most common cause of oil leaking into the spark plug chamber and is it an easy fix or costly?

You mean there was oil on the plug and inside the plug cap? Maybe there was oil spilt at the last oil change or else you have an oil leak, have a look and see where the oil might have come from.

Wailin

No there is oil getting into the spark plug chamber because it's misfiring again on start up since I changed the plugs the other day. I'd say it's either the valve seal gasket or the rocker gasket. It's driving fine once I get moving, it's just the start up.

newmember2

You mean the combustion chamber? It wouldn't be the rocker cover then, and if it's outside the engine then it wouldn't be the valve seals.

You said "when I removed the ignition coils, one of them was covered in oil", does this mean when you pulled off the plug cap there was oil all over the plug and down where the plug is screwed into the head? If so, and there's new oil there now after having cleaned it recently, then you have a leak.

CJhaughey

I have seen a Jimny with very corroded wiring around the ignition system.
Check the connectors that feed the coils as well, this car had green oxidation all over the terminals and was running badly.

Wailin

newmember? wrote: »

You mean the combustion chamber? It wouldn't be the rocker cover then, and if it's outside the engine then it wouldn't be the valve seals.

Eh, ok...

newmember2

Wailin wrote: »

Eh, ok...

Apologies, I'm not familiar with the 'spark plug chamber'.

TheBoyConor

it could be broken piston rings too. If that is the case, it is curtains for the jimny. It would not make sense to repair.

saabsaab

TheBoyConor wrote: »

it could be broken piston rings too. If that is the case, it is curtains for the jimny. It would not make sense to repair.

Maybe not, you could try the gasket repair fluid added to the oil. Sometimes these work swelling the seals slightly and forming a better seal. A bit of the black arts I know and some won't approve but worth a try at around 12 euro a bottle.

saabsaab

Of course it won't help a broken piston ring but that may be unlikely if the oil has been changed regularly.

Wailin

Why would it be curtains lads if it's the piston ring? Can they not be replaced like most gaskets?

saabsaab

I wouldn't say its a piston ring, maybe a valve seal?



The labour cost and parts, ring and gaskets might be more than the value of the vehicle depending on age etc. Look up done deal to see values for your model and year to see if it would be worth it if that's the case.

Boxcar_Willie

Sounds like valve stem seal .
Very cheap to buy , bit of work fitting though .

saabsaab

Labour cost again re valve seal. Try the magic bottle!

Wailin

I was thinking (hoping) valve seal myself, as I could probably do it myself. In the video below, its the gaskets that seal each of the 4 spark plug yes?

https://www.youtube.com/watch?v=3BBwPkWpaec

Wailin

Cheers lads. So the best outcome would be the a worn valve cover o ring that's leaking oil into the spark plug tube? Is that a possible scenario too?

saabsaab

What year is the Jimny?

Wailin

Lizbeth Quiet Self-help wrote: »

Where is the oil? Is it on the upper surface of the spark plug, or the electrodes? As in, is the oil above or below the threads?

The oil was on the bottom of the couil when I removed it from the spark plug and I could see oil on the top of the plug when I looked in the plug well. When I removed the plug it had oil around the threads.

saabsaab wrote: »

What year is the Jimny?

It's a 2002 but has a 1.6 engine from a 2004 Suzuki Liana

saabsaab

From what you say it sounds like the oil leak is causing the coil over the spark plug to short and in turn cause a misfire.



The oil on the spark plug is only due to it seeping down onto it when you take it out to investigate and is therefore a red herring.


Look at where the oil is leaking from, could be a hose or the rocker cover gasket, if that is the case an easy fix as per your video link.

TheBoyConor

Wailin wrote: »

Why would it be curtains lads if it's the piston ring? Can they not be replaced like most gaskets?

You'd have to dismantle most of the engine. For an aul Jimny, it simply wouldn't be worth the hassle, time or expense to do it.
Generally when something of that nature goes wrong of a car of this age you'd just scrap it or at best fit a scrap yard engine into it if you could get one at a cheap price.

If it was a newish valuable car or a classic car then the engine could be either repaired or more often, overhauled completely with many new parts fitted given the level of dismantling involved. This is super expensive though and only done when you can't get a replacement engine. you'd be mad to invest so much in a car like this.

Tacitus Kilgore

Saabsaab speaks truth,


Valve stem seal wouldn't be wetting a coil pack with oil lads....

A leaky rocker cover gasket or o-ring, or possibly poorly directed pcv will do that, mostly likely filling up the chamber and shorting the coil/plug connection.

Don't be going changing piston rings because there's oil on the outside of a spark plug..

TheBoyConor

Wailin wrote: »

It's a 2002 but has a 1.6 engine from a 2004 Suzuki Liana

In light of that I would say just clean off the plug to get her going nice and then just drive her on till she calves and then scrap her.
Jimny of that age isn't worth hardly the cost of a regular service, not mind a significant engine repair.

You could try yourself to fix it if you are willing to pump hours and hours of time and a couple of hundred euros is parts and tools into it. But be advised, unless you are experienced at this kind of work and know what you are doing, or have a knowledgeable friend willing to donate their time, you might well end up with more problems than you began with or just a completely non-functional engine.

saabsaab

Tacitus Kilgore wrote: »

Saabsaab speaks truth,


Valve stem seal wouldn't be wetting a coil pack with oil lads....

A leaky rocker cover gasket or o-ring, or possibly poorly directed pcv will do that, mostly likely filling up the chamber and shorting the coil/plug connection.

Don't be going changing piston rings because there's oil on the outside of a spark plug..

Plus one on this, may be an easy fix.

Wailin

TheBoyConor wrote: »

In light of that I would say just clean off the plug to get her going nice and then just drive her on till she calves and then scrap her.
Jimny of that age isn't worth hardly the cost of a regular service, not mind a significant engine repair.

You could try yourself to fix it if you are willing to pump hours and hours of time and a couple of hundred euros is parts and tools into it. But be advised, unless you are experienced at this kind of work and know what you are doing, or have a knowledgeable friend willing to donate their time, you might well end up with more problems than you began with or just a completely non-functional engine.

Ah I've put a lot of work into it myself over the last few months. Gave it a small lift with a complete suspension change, steering damper kit, all brakes changed, changed coolant, full service etc. I'm thinking it's just the o ring for the spark plug shaft myself. It's running well and not miss-firing since I changed the plugs. It's a deadly little yoke and I'd hate to have to scrap it. But I wouldn't be stupid enough to pump a heap of cash into it if it was something more serious.





Cheers for the advice folks. I'll check it again over the weekend and might order the o rings. It's not using any oil, level is still the same since I did the oil change.

Wailin

The responses I'm getting from the bigjimny forum over in the uk seems to point to the o ring too. Apparently it's common enough. Fingers crossed!

Wailin

It's a tiny lift. Barely noticeable

Tacitus Kilgore

Wailin wrote: »

It's a tiny lift. Barely noticeable

I see no lift :pac:

Wailin

Just to update, I eventually got around to removing the rocker cover to check the spark plug gasket seals.



The gasket on the problematic spark plug did look worn so I replaced it and left the rest and rocker cover gasket as they looked good.

Old gasket



New gasket



I started it up and drove around for awhile. Came back and removed coil and plug. No oil and everything looked good so fingers crossed that's all it was.

saabsaab

Well done, cheap fix in the end.

mickdw

Cool little thing.
I drove one there a few weeks back identical to yours without the mods. Unbelievably tiny to the point of being funny.

Wailin

When you have a couple of large people in it, it is comical!

TheBoyConor

expect some of the other three seals or the rocker cover seal to start leaking before too long.

the general rule here is if a cover is removed which disturbs seals, change out all the seals. even if they look OK, they are old and have now been interfered with. Can't be trusted anymore. Seals are cheap. Labour and inconvenience to go at it again are expensive.