62 replies to this topic

[Foxy]

I've had some issues with a weird 'misfire' on my supercharged VX and I wonder if these marks on the plugs are related to that problem.

 

 

3 of the plugs look like this but one looks fine.

 

I've had some good advice from the usual suspects but wonder if anyone else has any ideas as to what could be causing the 'dents'? 

 

Ideas so far include:

- detonation

- incorrect plugs (these new ones are standard - should they be special for SC)

- mapping issue

- fuel pump struggling at high load

 

We've ruled out problems with coil pack and cat.

 

The misfire manifests itself at high revs but couldn't be recreated on the dyno. On track, if you don't go over 6k rpm its fine but if you do it goes into limp mode.

 

It's stage 2 Courtnay map.

 

Any ideas? 

[Foxy]

The other plugs:

 

(thanks to Chill and Joe for their help so far )

[oakmere]

Looks like detonation to me, sure there has been similar before. Get this sorted if you want your engine to last much longer.

[pete-r]

How old are the plug? Multi pronged attack I'd suggest.... Change them to cooler plugs. What injectors are you running? If the green look at getting some VXR blues. About 120 inc the (throwaway) rail from Vauxhall. Longer term I would consider investing in the obdtuner, I've heard lots of rumour which are unproven in fairness, that the courtenay map runs rich. Is the knock sensor reading available? You could go back to courtenay but for the cost of the trip there and diagnostic time I'd go dutch. If you want to swap out any parts to try I think I've got a load of my old bits in the garage,

[pete-r]

Oh and gap them properly. Mine were brand new out of the box and were all over the shop!

[Mr Apex]

Worth checking - how old is your battery? I started getting a weird misfire and my AFR was showing lean, even at idle. It turned out that the fuel pump was unable to deliver sufficient pressure, which could have killed the engine. I changed the battery and that fixed the issue.

[CHILL Gone DUTCH]

Lol I thought this was on your Evora when you messaged me Honestly thought you had sc the Evora

[CHILL Gone DUTCH]

My new advice would be obdtuner 

[chris_uk]

get rid of the plugs and get iridium ones for a start, gap them to about 0.7 i think it is.

 

what fuel do you use?

[PaulCP]

Iridium plugs (can't remember which spec though) were fine on my Courtenay mapped car for years. How old is the map? If you're not wanting to faff around with the Dutch software might be a good idea to take it to Courtenay's on one of your trips to Norfolk for them to check & possibly update the mapping.

Edited by PaulCP, 07 June 2017 - 06:32 PM.

[The Batman]

What injectors are you running? If the green look at getting some VXR blues. About 120 inc the (throwaway) rail from Vauxhall.

He's on z20 injectors I think, also the vxr injectors set and rail is on back order with over 600 people waiting for them lol! Vauxhall finally figured it out. But I think you can get them individually for about £160 a set

[Foxy]

INFORMATION OVERLOAD! Thanks guys, bear with me while I digest all this

[chris_uk]

i still have a brand new set on the rail.. 

 

they are a customers who seems to have left the planet

[CHILL Gone DUTCH]

options

poor map

cracked exhaust throwing lambda readings out 

lambdas them selves 

fuel pump 

blocked air filter 

injectors stroke pump not able to supply enough fuel but you would think this would show its self when mapped 

or the fuel pressure regulator or boost pipe fell off or broke

[fiveoclock]

IME on my car the dents were caused by so.ething rattling around in the combustion chamber. Never found out what it was before the engine let go. Yo need to get a scope down there and check the piston crowns

[Steve.i.am]

Sorry to hear you're still having this misfire issue mate

 

 

[color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]- incorrect plugs (these new ones are standard - should they be special for SC)[/color]

 

I've had standard NA plugs in mine for the 4 years mines been SC and its been OK. When I had my car mapped at Courtney I asked them if the plugs would be OK and they said it'd be fine.

 

 

 

[Foxy]

IME on my car the dents were caused by so.ething rattling around in the combustion chamber. Never found out what it was before the engine let go. Yo need to get a scope down there and check the piston crowns

'Scope is on order - hope a £17 amazon thing is up to the job! Will post the pics, hopefully tomorrow I agree though, even it there are detonation issues, those dents are caused by something else.

[Foxy]

Worth checking - how old is your battery? I started getting a weird misfire and my AFR was showing lean, even at idle. It turned out that the fuel pump was unable to deliver sufficient pressure, which could have killed the engine. I changed the battery and that fixed the issue.

Good point, but it's been on a ctek recycle and I think it's fine...maybe something telling in the pump and fuel pressure though.

[CHILL Gone DUTCH]

 

Sorry to hear you're still having this misfire issue mate

 

 

[color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]- incorrect plugs (these new ones are standard - should they be special for SC)[/color]

 

I've had standard NA plugs in mine for the 4 years mines been SC and its been OK. When I had my car mapped at Courtney I asked them if the plugs would be OK and they said it'd be fine.

 

 

 

 

 

discussed  here

 

http://www.vx220.org...-boosted-z22se/

[Foxy]

get rid of the plugs and get iridium ones for a start, gap them to about 0.7 i think it is.   what fuel do you use?

Will try the plugs but I'd bet money that's not the issue. Fuel wise I haven't been overly fussy but normally use super.

Edited by Foxy, 07 June 2017 - 08:49 PM.