LSA misfire

[disorganise]

Hi all,

My F2 GTS has developed a misfire whilst sitting idle the past few months. Noticed it the other day when I went for drive and was also getting some ESC messaged - so figured low voltage, she'll be right once it charges the battery back up. the ESC messages disappeared and after maybe 30 mins or so the misfire seemed to sort itself.

I had to move the car yesterday and noted it was misfiring again. My OBD tool had carked it so bought another one and it arrived today (OBDLInk MX+). Confirms misfire on cylinder 8.

In about 10 days, I need to return to Sydney (from 'Melbourne'). So a couple of questions;

I don't know what plugs are in there, but I know they were changed. Had the engine tuned for an interchiller and CAI and there was something about cold plugs.

So question 1: will mixing plugs cause any issues? tentative plan will be to grab a new plug from supercheap on the weekend
2) are all compatible plugs going to be 16mm socket - cos I need to buy one of those too. Supercheap is probably the closest and is about 35km away so will buy this and the plug together.
3) If re-gapping the existing plug and/or replacing the plug doesn't work, would driving the 800 odd km to Sydney with misfire cause damage. Obviously there's less power and one would avoid planting the foot, but does a misfire in a single cylinder do actual damage? In Sydney I have ready access to mechanics and public transport, so it's just much easier there. But I won't risk damage.
4) What gap should I be setting?
5) Would there be some generic HT cable I can try as a stop gap too? I'm thinking it unlikely that the proper ones would be in stock

thanks for any help/advice.

[Peter B - CV8]

I'm pretty sure that Supercheap have an "in house" service for basic things & changing a spark plug should be encompassed by this. Sounds as though you've narrowed down the cylinder - which helps.
- Have you checked the HT connections & injector connections ?
- Pick up a cheap socket set & swap the spark plug to a different cylinder, then scan & see if the problem has shifted to that cylinder (thereby confirming that the spark plug is at fault).
- Whilst you've got the spark plug out, take photos of it so that you can quickly confirm you are buying the right replacement. They are usually pre-gapped, but eyeball the gap & see how it looks as a temporary measure. I'm old school & still check gaps on new plugs....

[whitels1ss]

If you are not sure that you know exactly what you are doing & have the right scanning tools
I would suggest taking it to someone (like a decent tuning shop) who does.


Could be so many things, even an intake manifold gasket or other vacuum leak,
(I have seen intake manifold bolts get a little loose, causing vacuum leaks showing up rough idle before
& you said that you have an interchiller on there so you would even have more gaskets to possibly be leaking.)

I certainly would not be driving it around in the meantime in case you do some very expensive damage.



Another thing, if you wanted to test for vacuum leaks yourself would be to spray something like brake clean
around where the intake manifold meets the heads & other areas with the engine idling to see if there is any variation to help locate any leaks
& obviously check all the vacuum hoses.

[whitels1ss]

You could also swap spark plug 8 with another spark plug then clear & re check code with your scan tool
and run same test again changing the plug lead & then even again changing the coil, obviously just change one part at a time.

If the fault moves with any part change to the changed cylinder you know you are on track.

[disorganise]

- Have you checked the HT connections & injector connections ?

HT yes. I injectors.....no. is that a simple plug connection?



Pick up a cheap socket set & swap the spark plug to a different cylinder, then scan & see if the problem has shifted to that cylinder (thereby confirming that the spark plug is at fault).
Yeah that's the plan. I wasn't planning to take the HSV there though, was gonna use the Jetta and get the bits n come back.

[disorganise]

If you are not sure that you know exactly what you are doing & have the right scanning tools
I would suggest taking it to someone (like a decent tuning shop) who does.


Understood. I can handle a plug and lead, and am prepared to reset the fault code. Beyond that, nope. Figured $50 in parts is worth trying versus a few hundred, but more importantly, time. I can't really take a day off right now to take it to a shop. As to "decent tuning shop"....only one I know is 900km away :/

Gasket leaks sound expensive. (Woulda had a crack at that as a young bloke and an old banger.... GTS....yeah nah). Hoping it's a fouled plug...but I guess it's then *why* did it fault. But if I can get back to Sydney, the tuning shop can sort it out.

[whitels1ss]

Gasket leaks sound expensive. (Woulda had a crack at that as a young bloke and an old banger.... GTS....yeah nah).
Hoping it's a fouled plug...but I guess it's then *why* did it fault. But if I can get back to Sydney, the tuning shop can sort it out.

You might even find that if you check the intake manifold bolts to the heads & if they are loose
1/4 or 1/2 a turn on a few of them might fix the problem? :cheers:

[whitels1ss]

Could be so many things, even an intake manifold gasket or other vacuum leak,
(I have seen intake manifold bolts get a little loose, causing vacuum leaks showing up rough idle before
& you said that you have an interchiller on there so you would even have more gaskets to possibly be leaking.)

I certainly would not be driving it around in the meantime in case you do some very expensive damage.




To make it a bit clearer in what I said, I was actually talking about the heat insulators that they normally fit
that go in between the heads & intake manifold when they fit an interchiller.

They use (silicone) gaskets on both sides of the insulators.

[Peter B - CV8]

HT yes. I injectors.....no. is that a simple plug connection?


Yeah that's the plan. I wasn't planning to take the HSV there though, was gonna use the Jetta and get the bits n come back.

The injector connections are electrical & need to "click" in. Rare for them to come loose - as long they were properly attached. Just check the one for cylinder 8 & make sure it's securely connected.

[disorganise]

To make it a bit clearer in what I said, I was actually talking about the heat insulators that they normally fit
that go in between the heads & intake manifold when they fit an interchiller.

They use (silicone) gaskets on both sides of the insulators.

ahh ok. Not that then. No heads/manifold removed. just a T piece on the AC gas and the Supercharger cooling circuit basically. It's a road car and TBH I got it figuring less heat in the SC will mean better longevity rather for any performance benefit.

[whitels1ss]

The insulators & thermal blankets are quite cheap & easy to fit,
I was looking to fit an interchiller on my old LS1 SS & was told by the guys who make them
that you get that much heat soak from the engine block & heads into the intake that they are well worth fitting
& it was a normal thing to go with them for best results.

The way he was talking, I thought they fitted the lot together on most cars.

Anyway, sorry if I presumed wrong but your intake bolts could still be a little loose,
certainly would not hurt or cost anything to check.

[disorganise]

So I managed to get down to supercheap just before closing. Got a plug socket set and a plug.
Socket included the right size (good start) but the extension bar was way too long - luckily I have a shorter extension here and could just about get the ratchet in there; talk about tight - no idea how you'd go on the passenger side, that look worse.

anyway....got the old plug out; bit oily as might be expected with unburnt fuel probable runnin about but no ahhaaa, that's why. Since I'd bought another plug, figured I'd drop that in rather than take another plug out to see if the fault moved along - bit less knuckle grazing.

Good news! misfire seems to have cleared up :) Still intend to get it check properly when I get back to civilisation, but hopefully the new plug will get me the 1000km no worries.

But....one small issue. How so I clear the engine light warning?
OBDLink didn;t seem to do much after giving me it's warning.
Torque seemed to clear the codes, but lied. OBDlink still shows 70km since MIL. Is there some trick, or another software I need? It bothers me only from the perspective that if a genuine new fault arises, I won't necessarily know because the check engine light is already lit

[whitels1ss]

Good news! :cheers:

Sorry but I am not sure why you can't clear the code, I have never had problems with my scan setup.

[VLSteve]

But....one small issue. How so I clear the engine light warning?
OBDLink didn;t seem to do much after giving me it's warning.
Torque seemed to clear the codes, but lied. OBDlink still shows 70km since MIL. Is there some trick, or another software I need? It bothers me only from the perspective that if a genuine new fault arises, I won't necessarily know because the check engine light is already lit

I've had better luck with Torque Pro over the free version.
Otherwise, try disconnecting battery for 20min?

[disorganise]

I've had better luck with Torque Pro over the free version.


I have pro - bought it years ago.

I found the 'trick' this earlier today. When Torque pops the warning message, it says some vehicles require the engine to be started immediately after the clear code. Ta daaaaa :) I hit clear and when the counter got to 80 odd % I hit the start button. Few seconds later the engine light went out - yes!
Rechecking for errors there's something random/multiple misfires detected but I think that might have been to do with the reset. OBDLink also sees the same, but the cylinder 8 misfire is gone and the time/distance since MIL and DTC are zero. Like I said the engine light is now out so I know if it comes back something is wrong.

Of course - if there's a proper way to clear the code (should be when engine is running, or should be stationary and start 2 seconds after hitting clear) then I'm all ears. Clearing whilst stationary and in accessories mode isn't it, I know that :)