Technical Misfire on start up

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Technical Misfire on start up

Keithjecks

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Sep 8, 2011
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i have a strange problem with my Panda. Almost from new, it has misfired when started from cold. It seems to start on two or three cylinders. If you rev it to 2,000 rpm for a few seconds it fires on all four cylinders and thereafter runs perfectly. WHen the car has the spark plugs replaced the problem goes away for a couple of weeks, but then returns. I can't think what the problem is. Any one else had the same issue?
 
I had something similar, I'm not saying it's what you suffer, but it may help.

Fitted a new set of spark plugs and our 1.1 Active popped and stuttered on idle.
Pulled off and checked all the plug caps, still the same.
Put the old plugs back in and it was ok.

Turned out two of the spark plug gaps on the new plugs were closed up too far (either knocked about or came from the factory like it)

Seems to me that if they are "pre gapped", they don't stay that way in the box!

Set them up properly with a gauge and it runs perfect.
 
Possibly HT leads. I'd try changing them first, had similar on a Brava once, new leads sorted it :)

To be honest, HT leads very rarely fail. I've had sets that are over 15 years old which have been fine on tuned engines that have been checked on the dyno. Also OEM leads cost. I seriously doubt it's that.

Could be spark plug, but if it clears I wouldn't overly worry really.
 
To be honest, HT leads very rarely fail. I've had sets that are over 15 years old which have been fine on tuned engines that have been checked on the dyno. Also OEM leads cost. I seriously doubt it's that.

Could be spark plug, but if it clears I wouldn't overly worry really.

I disagree entirely. HT lead failure will vary depending upon the cars use and system setup. Some cars it'll be commone on an others not so.
 
I disagree entirely. HT lead failure will vary depending upon the cars use and system setup. Some cars it'll be commone on an others not so.

Not in my experience. I think the reason for HT lead failure is often because people replace with cheap parts. For ignition systems I always have everything OEM.

HT Leads are generally not cheap either. Sure the OP could splash out and buy some but a slight miss on startup does not really indicate HT lead failure. I don't want the OP to spend money he may not need to, that's all.
 
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Not in my experience. I think the reason for HT lead failure is often because people replace with cheap parts. For ignition systems I always have everything OEM.

But is that not a contradiction of sorts? If the OEM ones don't normally fail then why would someone change them with cheap parts?

HT leads are only rubber at the end of the day and considering the tension they're placed under and conditions they operate in, it's surprise more don't fail more often IMO.
 
But is that not a contradiction of sorts? If the OEM ones don't normally fail then why would someone change them with cheap parts?

HT leads are only rubber at the end of the day and considering the tension they're placed under and conditions they operate in, it's surprise more don't fail more often IMO.

People, more often than not, replace their OEM HT leads with cheap aftermarket ones, in the false belief that there is something wrong with the original ones.

They rarely fail IME. As I've said, I've had leads that are 15 years old working perfectly fine, on the dyno on a modified engine. Given this is a much younger car (okay it is Italian), I seriously doubt this is the problem. Unless OEM Fiat leads are absolutely rubbish?
 
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All you need is to have them removed by a heavy handed mechanic who yanks them off when changing the spark plugs and it can weaken them.

It's not common for them to fail but not impossible. All the cara I've had them fail on have been low mileage strongly enough, 10 year old Brava with 30k on the clock and a few 15 year old Pandas with similar mileage.

I suppose they get a lot more of the extremeties in the winter etc if sitting on a engine that isn't used much.
 
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