Misfire..Coil Pack?

Author
Discussion

98elise

Original Poster:

28,294 posts

169 months

Thursday 4th December 2014
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About a 18 months ago our MX5 started Kangarooing, and a change of plug leads sorted it.

Its just started up again, so this morning I coated the coil packs and leads in WD40. Its a bit better but still happening, so it does seem to be the ignition.

Would you try replacing the coil packs next, or would you suspect leads again?

VladD

8,011 posts

273 months

Thursday 4th December 2014
quotequote all
You have to be a bit careful doing this, but....

if you take out each spark plug, put it back in the HT lead and earth it against the engine block, and then turn the engine over, you'll be able to see if a spark is getting generated in each plug. If you find that one isn't, then you can swap some HT leads over to try and work out if it's the plug, lead or something else.

Of course there could be other reasons, but that'd be a good check to start.

98elise

Original Poster:

28,294 posts

169 months

Monday 8th December 2014
quotequote all
VladD said:
You have to be a bit careful doing this, but....

if you take out each spark plug, put it back in the HT lead and earth it against the engine block, and then turn the engine over, you'll be able to see if a spark is getting generated in each plug. If you find that one isn't, then you can swap some HT leads over to try and work out if it's the plug, lead or something else.

Of course there could be other reasons, but that'd be a good check to start.
Th coil packs fit direct to the top of two of the spark plugs so its not really an option to try that.

VladD

8,011 posts

273 months

Monday 8th December 2014
quotequote all
98elise said:
VladD said:
You have to be a bit careful doing this, but....

if you take out each spark plug, put it back in the HT lead and earth it against the engine block, and then turn the engine over, you'll be able to see if a spark is getting generated in each plug. If you find that one isn't, then you can swap some HT leads over to try and work out if it's the plug, lead or something else.

Of course there could be other reasons, but that'd be a good check to start.
Th coil packs fit direct to the top of two of the spark plugs so its not really an option to try that.
On my Mk1 the coil pack is attached to the bulkhead. A picture, not of my car, to illustrate.


MX-5 Lazza

7,954 posts

227 months

Monday 8th December 2014
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I take it you have a Mk2.5 then?

You can still do the same thing, it's just not quite as easy.