Misfire/running on 3 cylinders/ignition coil problem
Discussion
Hi all,
Having a problem it seems many others have also had. 145k miles on the clock on my 1999 mkII and it doesnt want to start on all cylinders when the engine is hot - i.e. when i've driven it/had the engine on, then tried to start it again whilst the engine is still warm.
So far we've tried adjusting the crank position sensor (well, we didn't adjust it as it was spot on the gap my Haynes manual gives), cleaning up the connections on the HT leads/coil pack, and changing the spark plugs, but to no avail.
I've bought a new coil pack and will try that tomorrow. However we've tested the resistance on the current one and it seems, again, within the tolerance the Haynes manual gives. Does this mean anything - does anyone have experience of replacing this despite measuring fine and it solving the problem? Or experience of replacing the coil pack and that not being the solution?
Any ideas welcome. I have some access to a diagnostics test through a friend, but I'm dubious as many say this sort of thing will not show up in that and mechanics often just try the same things I am until they find a solution. Thanks.
Having a problem it seems many others have also had. 145k miles on the clock on my 1999 mkII and it doesnt want to start on all cylinders when the engine is hot - i.e. when i've driven it/had the engine on, then tried to start it again whilst the engine is still warm.
So far we've tried adjusting the crank position sensor (well, we didn't adjust it as it was spot on the gap my Haynes manual gives), cleaning up the connections on the HT leads/coil pack, and changing the spark plugs, but to no avail.
I've bought a new coil pack and will try that tomorrow. However we've tested the resistance on the current one and it seems, again, within the tolerance the Haynes manual gives. Does this mean anything - does anyone have experience of replacing this despite measuring fine and it solving the problem? Or experience of replacing the coil pack and that not being the solution?
Any ideas welcome. I have some access to a diagnostics test through a friend, but I'm dubious as many say this sort of thing will not show up in that and mechanics often just try the same things I am until they find a solution. Thanks.
Although you have already bought a new coil pack, changing the HT leads will be easier to check out before you attempt the hellish task of changing the coil pack (do you know someone locally whose leads you could use to test?). I would recommend doing this first, and then do the coil pack. But I reckon it will be the coil pack!
So after this advice I cancelled the coil pack and just got the HT leads instead, which I installed today. This combined with new spark plugs has made it run much better, so all looking good.... from cold. Warm start worked initially after imediately turning back on, then after 5 minutes. But 20 mins later and same old problem.
Next thing is to re-order that coil pack I guess - will see if that solves it as a few of you have said that now too. £40 down so far, about to be about £150 so hoping this solves it.
Next thing is to re-order that coil pack I guess - will see if that solves it as a few of you have said that now too. £40 down so far, about to be about £150 so hoping this solves it.
So we fiddled with connections on those HT leads before doing anything with the coil pack and all seems fine. It misfired once about 20 mins after warming up (was fine before that), then every other time it has been running better than ever so it seems a bit of vibration or moisture just stopped a connection somewhere.
Sounds like it's still a problem if it happened once... but have tested it numerous times now, warming the engine up, turning off then on, waiting 30 mins or an hour, trying again. And has all worked. Going to run it for now and see if I encounter the problem again, so far after a day of running back and fourth and testing in the drive-way all seems A-OK.
Sounds like it's still a problem if it happened once... but have tested it numerous times now, warming the engine up, turning off then on, waiting 30 mins or an hour, trying again. And has all worked. Going to run it for now and see if I encounter the problem again, so far after a day of running back and fourth and testing in the drive-way all seems A-OK.
The HT leads DID NOT solve the issue. Warmed her up, and she re-started fine after 1 minute then after 20 mins. After about an hour though it was back to the same problem. So i ordered a new coil pack and installed that today - so far so good, seems to start fully every time now but that is still onyl with a couple of tests.
So now I really will run it and see what happens - hoping this is fixed because after driving a VW UP! (great little car for its purpose by the way) for a week I am sorely missing the MX5
So now I really will run it and see what happens - hoping this is fixed because after driving a VW UP! (great little car for its purpose by the way) for a week I am sorely missing the MX5
I too had the same symptoms on my 1999 NB ... I had hoped it was the leads and or plug, changed these and the same so bought a coil pack and been fine since and that was 2 years ago... I bought a brand new one from a place in Hainault for £63 with a two year guarantee. I wasn't planning on keeping the car this long so thought well if it lasts 2 years hat will do me but I still really like the car and its turned out to be a keeper.
The company that was selling them soon con to the fact they were so cheap compared to a genuine one and promptly put the price up to £160.
The company that was selling them soon con to the fact they were so cheap compared to a genuine one and promptly put the price up to £160.
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