Fabia 1 1.4MPI Misfire

[Jevans]

I have a 2002 Fabia 1.4MPI which intermittently misfires. The engine light came on so I took it to the dealer who says Cylinder 2

is showing up and could be plugs, injector or coil. I measured across the injectors for resistance and they are all the same. The coil s are a single pack with just 4 wires in the connector so my question is: Can I measure the resistance of each coil as I have tried to measure each to earth with no luck. Before I take it back for a more thorough look by the dealer I would like to narrow it down.

Any help would be appreciated. The car has done 26K and we have had it from new. This is the first problem we have had.

Thanks in advance

John

[KenONeill]

Your description reads like the car has a double-ended coilpack using the "lost spark" principle where both cylinders at TDC are sparked (one is on compression stroke and fires; the other is on the end of the exhaust stroke). If that's correct, then it's unlikely to be the coilpack if it's only misfiring on 2 and not on 3 as well. You can check the coil resistance as you propose, but you'll need the resistance spec for the Furbie.

I'd think the problem is likely to be the spark plug or HT lead, and parts (set of plugs and leads) at a motor factor are likely to be less than an hour's labour in Bournemouth!

[Jevans]

Thanks for the quick response Ken, actually now you mention it the mechanic did mention that it did show cylinder 3 as well on one of the readings.

A new coil pack is £80 which may be the cost of the dealer investigation then I would have to pay dealer prices for the part.

The misfire is under heavy load which makes me think it is a coil breaking down.

There are no HT leads as the coil pack sits straight onto the plugs. I think I'll get a new set of plugs first even though they look good and see how it goes.

John

[KenONeill]

Ok, this pre EMS days, but I've seen good mechanics mystified by bad spark plugs. One guy went to the extent of swapping 2x40DCOEs for a single compound (fortunately, he had both) before realising that his misfire wasn't a fuelling issue!

[fabrel]

When I suspected my coil pack was failing I waited till it was dark and sprayed it with water. Supposedly if it's failing you're able to see it sparking/arcing like old ht leads. It did so I changed it. Cost about 50 at the time. Price increased since but still £20 cheaper than 80. http://partsforallcars.com/spares/product_info.php?products_id=41859&manId=SKODA&modId=FABIA&engId=1.4

Might be able to find a bargain on ebay too.

[Avalon]

£70 ish from ECP for a coil pack by Valeo inc discount. If you have the kit to read fault codes (£6 lead and free VCDS lite or a hand held unit) swap the plug on the affected cylinder with a known good cylinder and see if the fault moves with it.

[Avalon]

£19.99 delivered on eBay for a used one...

[anewman]

Just replace the plugs regardless. Hardly any point swapping one to the other and playing with diagnostics when they've probably covered 26k miles and are 11 years old.

[Avalon]

They have a 40k/4 year interval same as air filter and PAS fluid check so 'should' be about 3 years old and have covered less than 9k assuming the service schedule has been followed?

[Jevans]

Well I have changed the plugs and so far all seems well. No misfire and no engine light. The manual says the plugs are good for 40,000 but probably didn't take into account the time to get to that mileage. Anyway thanks to everyone on here who replied and helped me save a fortune.

Keep up the good work.

John

[Avalon]

It's nice when it's a simple and cheap fix and even better when you can do it yourself

[Jack M]

Just a quick one while thisis on here, my engine has a slight stutter on it at idle but doesnt miss a beat whiledriving, someone said it may be something to do with the throttle body, anyone else had antything like this ?

[anewman]

It's normal on this engine. Idle kept close to stall to meet emissions legislation. A throttle body clean wouldn't hurt though.

Sent from my Blade using Tapatalk 2

[Avalon]

Lumpy idle is a known feature of the engine, it's been suggested that increasing the air intake yo say 70mm + will improve this. I stripped my TB at 40k (12 years old) and it was pristine, I was slightly disappointed if I'm honest as I had hoped it would need cleaning and improve responsiveness and possibly fuel economy fractionally.