Melted spark plug!! Causes?

[Sir_Dave]

So trackday at Donington yesterday, did about 30 mins epic running, then misfire, P302 (should be cyl2) on Scanguage.

Pulled everything apart, fitted new leads/coilpack off a friends Cooper S, same problem, pulled pugs out to be greeted by the following:

Cylinders 1>2>3>4 left to right.

Bottom set had been in 12 months or so and are the first set we took out. Plug in cyl1 had melted (weird how scanguage gave the wrong code?), assuming due to overheating through lack of fuel? Car was running fine up until the misfire, but IATs were rising up to 50°C just before the issue occurred, which seemed pretty hot?

On the 2nd set from Halfords (all they had), the car was epic for 15 mins, then same issue again, plug in cyl1 had melted causing misfire.

Car is running newman cam/450 injectors and Mynes tune from 1320.

Initial thought is the injector on cyl1 might be goosed, but im no mechanic so open to other suggestions?

Car ran fine to get me home, so assuming the issue has only reared its head due to extensive high temp/high load running on track

 

[Gaverick]

I'd be looking at the injector too as you suggest. It would seem cylinder 1 is running lean due to lack of fuel and getting very hot. Hopefully no damage has been done to the piston.

 

[Darren S]

I'd be looking at the injector too as you suggest. It would seem cylinder 1 is running lean due to lack of fuel and getting very hot. Hopefully no damage has been done to the piston.

Exactly. There's a spark plug tip knocking about somewhere - or by some bloody good luck, it cleared the exhaust valves and got spat out?
Are those injectors new?

D.

 

[Feirny]

Exactly. There's a spark plug tip knocking about somewhere - or by some bloody good luck, it cleared the exhaust valves and got spat out?
Are those injectors new?

D.

We reckon it spat it out.

 

[Sir_Dave]

Exactly. There's a spark plug tip knocking about somewhere - or by some bloody good luck, it cleared the exhaust valves and got spat out?
Are those injectors new?

Injectors were 2nd hand, fitted by previous owner (Sarah's brother) a couple of years back.
Im hoping that as its running fine now, i.e. no misfires etc, it would indicate that there is no further mechanical damage?
As Greg says, we reckon it might have spat it out, otherwise it would be running like a pig permanently.

 

[_Tom]

I had the same with my 200sx many moons ago -

Caused by det. Just got far far too hot. Never did any engine damage so i'm guessing it was spat out on mine.

 

[Willo40]

Strange thing is, the colouring doesn't look too bad if its been running really lean, I would expect them to be a lot lighter looking? like really grey?

 

[reedy107]

Ouch..not good. Hope u get ot sorted mate

Ben

 

[...]

Dave silly question, are they the right temp plugs for the application ? eg when highly modded then a different plug is often specified(a cooler running plug) to stop that ?



not the same car type of even forced induction but this will give you an idea about plug temps

http://www.imps4ever.info/tech/engine/sparking-plugs-spark-plugs/spark-plugs.html

 

[Mr Burns]

Gutted to see you having issues mate, especially on such a critical day. Hope it's a simple and inexpensive fix!

 

[Dan@SJM]

Det usually. Have you had the map checked to make sure it's not running lean?

 

[Sir_Dave]

Dave silly question, are they the right temp plugs for the application ? eg when highly modded then a different plug is often specified(a cooler running plug) to stop that ?

Yeah, was mapped by 1320 on the 7's a couple of years ago, but yes, perhaps i should have gone to the 8's for trackday due to extra heat/loading?

Gutted to see you having issues mate, especially on such a critical day. Hope it's a simple and inexpensive fix!

Tell me about it, was the 1st day with the car, so was supposed to be a bit of a shakedown, but expected to use it more than i did lol!!

Det usually. Have you had the map checked to make sure it's not running lean?

Not yet, but when 1320 did it originally it was a very "safe" map, so well within fueling/rev limits etc. Only thing i can think re: that is that the s/c belt that was on it when it was mapped was apparently slightly too long, & i now have the correct one, possibly giving more boost at higher revs, meaning that its a bit too lean - although wouldnt that affect all cylinders?

Think the graph below shows the limits at the top end?

 

[Ph1 Tom]

Never had anything but issues with NGK plugs on various cars. Some people swear by them, I swear they're s**t.

I always use the appropriate temperature Denso plugs. Yours is tuned so I'd go one step colder.

IK20 is for the normal Cooper s and IK22 is for the works (197-214bhp), so would get some IK22 Denso plugs.

Then when you've got decent plugs of the correct temperature fitted get the map checked.

 

[...]

Have to say i swear by Denso's too , always had em in all my race engines both 2 and 4 stroke


and i am more convinced that a plug failure issue to running too hot than it being a det issue ......

 

[STEVE.M]

meaning that its a bit too lean - although wouldnt that affect all cylinders?

/QUOTE]

Exactly,only one cylinder is eating the plug.Faulty injector??

 

[Ph1 Tom]

and i am more convinced that a plug failure issue to running too hot than it being a det issue ......

I completely agree

 

[...]

pull the injectors (all of them , and have them cleaned and checked , but the plugs seem an issue

 

[Dan@SJM]

The only plug failures I've come across have been due to det.

 

[Lal B3N]

Happened on my astra gsi. It was held flat out at 3 figures for too long and then bang. Cylinder 3 ate the spark plug. Sadly mine needed a new engine lol.

 

[Ph1 Tom]

The only plug failures I've come across have been due to det.

But det can be caused by the spart plug.

 

[STEVE.M]

But det can be caused by the spart plug.

I think you are confusing this with pre ignition,which can be caused by a red hot plug tip,and the burn starts at BDC,usually resulting in a hole in the piston.
Japanese sports bikes run either NGK or DENSO plugs at twice the rev`s of a mini,with close to 190 bhp per litre,so plug failure twice in one day is unlikely on a mini,especially as it`s the same cylinder.I`ve never seen a plug failure on modern bikes either.
Ignition issues are unlikely,as I believe mini`s run 2 double ended coils,so anything going wrong on No 1 should be echoed in No 4.
Inlet air leaks are ruled out because its supercharged?Would probably run rich.
My money would be a faulty injector on No 1 cylinder making it run weak.
A visual inspection of the piston crown if it`s possible,along with a dry and wet compression check would be good for your peace of mind.
My money is on a faulty injector on No 1 cylinder.
Good luck with it,and have a poke round the mini forums.I had a quick look,but couldn`t find a similar problem.

 

[_Tom]

I still think Det is high on the list. Especially with it just having a new "correct" belt. More boost needs more fuel. Can you see what boost you are now running?
How good are the fuel pumps on these?

 

[STEVE.M]

I still think Det is high on the list. Especially with it just having a new "correct" belt. More boost needs more fuel. Can you see what boost you are now running?
How good are the fuel pumps on these?

Yes,detonation it is,on ONE cylinder ONLY,caused by a weak mixture by that cylinders faulty injector.
The other cylinders get the same boost,and share the same fuel rail!

 

[_Tom]

Yes,detonation it is,on ONE cylinder ONLY,caused by a weak mixture by that cylinders faulty injector.
The other cylinders get the same boost,and share the same fuel rail!

If you look above I have posted a picture of the exact thing happening in ONE cylinder ONLY on a 200sx I had.

 

[Dan@SJM]

Yes,detonation it is,on ONE cylinder ONLY,caused by a weak mixture by that cylinders faulty injector.
The other cylinders get the same boost,and share the same fuel rail!

It also depends what end the rail is fed.

 

[RSTuning]

That's detting badly on all 4

 

[Sir_Dave]

That's detting badly on all 4

Through lack of fuel i assume? Wonder if the injectors have maxed out with the extra boost. Will go for 550s and get the map changed to suit i think

 

[Dan@SJM]

Lack of fuel/too much ignition.

 

[Sir_Dave]

So after running perfectly for 18 months on road/track, this happened again at Bedford on Saturday:

Both times it threw a P301 on the Scanguage i.e. misifre in Cyl1.

The car is ONLY ever run on VPower (& was mapped on it), so had a full tank of VPower at Shell to begin with, i then did 150 miles or so on track in the morning, then i had to fill up at Bedford with their "Superunleaded" at lunchtime. My assumption is their "Super" is either faulty, or the Octane level isnt anywhere near 99? Plug on the right has been in for 12 months/1500 miles, then did 1 "proper" lap before failing, with the one on the left lasting 3 laps, i.e. 2 warm up, then literally 20 seconds of full power.

Would my assumption re: fuel quality/octane level being too low stack up?

 

[Waitey]

So after running perfectly for 18 months on road/track, this happened again at Bedford on Saturday:

Both times it threw a P301 on the Scanguage i.e. misifre in Cyl1.

The car is ONLY ever run on VPower (& was mapped on it), so had a full tank of VPower at Shell to begin with, i then did 150 miles or so on track in the morning, then i had to fill up at Bedford with their "Superunleaded" at lunchtime. My assumption is their "Super" is either faulty, or the Octane level isnt anywhere near 99? Plug on the right has been in for 12 months/1500 miles, then did 1 "proper" lap before failing, with the one on the left lasting 3 laps, i.e. 2 warm up, then literally 20 seconds of full power.

Would my assumption re: fuel quality/octane level being too low stack up?

100% crappy mapping. Probably why it's not making power either. For this to happen twice is more likely to be map related than anything else.

Your "running perfectly" has just been the car slowly eating spark plugs, which isn't perfect in my book.

I'd get:
New coil
New leads
New plugs
Refurbed injectors

Then get it mapped somewhere other than 1320....

 

[Sir_Dave]

Then get it mapped somewhere other than 1320....

I cant get it mapped anywhere else lol, not buying a standalone for it!!
Its done 3 trackdays since the map was adjusted, AFR's etc are all fine, Charlie at SRR said it seemed ok etc. Surely if the map was bad, it would have sh4t itself ages ago, and not done 150 miles fine in the morning, then eaten a plug after putting different fuel in it? Sarah's dad did think that there should be more "knock-control" on there to try & avoid this sort of thing though?

 

[Iain C]

Interesting thread. My Clio did this a few years ago so I changed all the injectors. Mine has been remapped too. May just go back to standard map.

 

[R3k1355]

What fuel did you put in it?
Did you fill the tank or just put a splash in?

 

[Matt W]

What fuel did you put in it?
Did you fill the tank or just put a splash in?

'Superunleaded' as per his post

You'd think fuel at a racetrack would be good quality with the sheer price of it though!

 

[Sir_Dave]

What fuel did you put in it?
Did you fill the tank or just put a splash in?

Filled it in the morning (to full) with the usual Shell VPower, then put half a tank of their "Super" unleaded in at lunchtime.

 

[JamesBryan]

Odd one this, as i'm sure a lot of people use the circuits 'super unleaded' and not had problems.

I use Oulton's fuel quite a lot and it seems ok.

There must be some tolerance built in to the map to allow for slight fuel differences, even V-Power from station to station could vary.

Possibly look at getting the injectors looked at and flow matched for consistency.

Annoying thing to happen anyway.

 

[welshname]

Have you thought about running an AFR gauge and seeing if you notice it running dangerously lean at any point? For me it suggests that either there is an intermittent fault with the injector or the mapping is bad.

Actually it could even be the fuel pump giving up and not being able to provide enough flow that high in the rev range. Don't know a lot about these cars but could it even be as simple as needing a fuel filter replacing as it's causing too much restriction for the flow needed at that power?

 

[R3k1355]

The fuel filter on the R53 is supposedly a lifetime jobbie, but some people have seen them be pretty nasty if they've not been changed.

If the fuel at the track had sat around for a while it can loose some of it's fizz, but it does take a little while, how many track days is the place running over winter anyway?

 

[R3k1355]

Have you thought about running an AFR gauge and seeing if you notice it running dangerously lean at any point?

or a knock monitor to see when it start detting

 

[Waitey]

I cant get it mapped anywhere else lol, not buying a standalone for it!!
Its done 3 trackdays since the map was adjusted, AFR's etc are all fine, Charlie at SRR said it seemed ok etc. Surely if the map was bad, it would have sh4t itself ages ago, and not done 150 miles fine in the morning, then eaten a plug after putting different fuel in it? Sarah's dad did think that there should be more "knock-control" on there to try & avoid this sort of thing though?

Sell the cam and use the OEM mapping?

I bet the map is only a tiny bit out. Ignore you did 150 miles on track before it popped. It'll have been going a tiny bit ever since it was fixed.

Change everything people have suggested. Injectors, put a bigger fuel pump in it, change the filter to an inline one. Stuff all the race boys do.

Its eating spark plugs FFS. Something is very wrong, not that its gone hard on 95 for an hour.