Technical Awkward Panda Spark Plugs

[JAMLAX]

Yesterday, I made an initial attempt to check (and replace if necessary) the spark plugs on my recently acquired 2004 Fiat Panda 1.2.
I successfully removed only one HT lead from the plug on the right hand side (i.e. the plug nearest to the timing belt).
Next, I carefully unscrewed the spark plug and satisfied myself it was in good condition.
However, my efforts to remove the three remaining HT leads from the other spark plugs were unsuccessful.

Any helpful suggestions will be appreciated - rather than me resorting to full brute force and ignorance to release these stubbornly stuck HT leads?

 

[ZaphodB]

Twist as you squeeze and pull, and never pull on the cable itself, always the rubber boot.

... and don't discount the idea that you might need to source a new cable set in the end...

 

[JAMLAX]

Thanks, I'll persevere with twist, squeeze, and pull on the rubber. Yes, I'm hearing this advice over the phone from my brother (mechanic) and as you say to avoid hauling on the actual HT cable leads.
Well, I'll keep all this in mind for my next attempt at checking/replacing the spark plugs. Probably I'll wait for a month or two since the engine is presently running sweetly enough.
Thanks for the prompt answer ZaphodB ... One way or another the task doesn't sound so daunting now that I have a sound plan of attack - and if I end up having to replace the HT leads so be it but it will be very satisfying if I manage Plan A rather than having to resort to plan B.
Within a month or so I'll aim to update on the eventual outcome.

 

[ZaphodB]

It's also worth preparing for the sudden release, thus avoiding damaging the lead in the process.

 

[portland_bill]

The HT leads should be considered a service item. It is usually difficult to remove them without damage.
I keep a set ready, although last time not needed.
If needed, get the NGK set, as they have the different boots for different plugs.

 

[koalar]

Pull at a slight angle they are not straight

Spark plugs, simple, quick, easy | FIAT Panda (Mk3)

Unplug the lead Unscrew the plug Screw the new ones in Torque up Plug the leads back on and drive off That's how it should go and often does Most of the problems are avoidable Don't change the plugs while it's raining Don't leave the plugs in past 100,000 miles Don't over torque Don't under...

www.fiatforum.com

There are tools to make it easier, I don't use one, but garages normally do

Spark plugs, simple, quick, easy | FIAT Panda (Mk3)

Unplug the lead Unscrew the plug Screw the new ones in Torque up Plug the leads back on and drive off That's how it should go and often does Most of the problems are avoidable Don't change the plugs while it's raining Don't leave the plugs in past 100,000 miles Don't over torque Don't under...

www.fiatforum.com

Gaps the import bit, it grows by 0.1mm per 6K eventually leading to a misfire and eventually damaging the coil

They start at 0.8 or 1mm depending on brand and start to fail at about 1.6-1.8mm

I swap somewhere between 12-20K miles it's not worth in my opinion re-gapping as the coating is getting thinner, once they are seized in they can be a nightmare to get out

 

[JAMLAX]

Koalar - passing on this know-how from your years of Panda mileage is very much appreciated.
From you and so many similarly helpful Fiat Panda owners - I've gained many excellent tips that are already helping my DIY car maintenance efforts.
Thanks again!

 

[JAMLAX]

I must make a confession.
Today, I went ahead and managed to undo all four spark plugs on the Panda. I checked the spark plugs and sort of 'improved' them with a gentle tap and a 'sandpaper shine-up'. However, to my dismay, after successfully putting everything back together (awkward though it was) I now find the engine is no longer running smoothly (it has been perfectly smooth up till now). The engine management light is now lighting up as I drive - flashing intermittently. Oh dear, oh dear, and many other despairing words!

P.S. I've ordered new Bosch HT leads and a set of NGK spark plugs but it could be Thursday before they arrive in the post.
P.P.S I'm hoping the 5 miles or so that I've driven with the engine sounding 'rough' won't have done any more damage than what I've managed to do today.

 

[koalar]

Pull the leads slightly and make sure they are all snapped on correctly

Does it idle really badly or is it only while driving

 

[koalar]

Don't panic you have only touch 4 wire and 4 plugs


Did you do them one at a time or all at once, is it possible a couple of leads could have been swapped over

One coil should go to cylinder 1,4 and the other to 2,3

 

[ZaphodB]

Make sure you didn't lose the 'nuts' on each plug as you cleaned them up.
Make sure those 'nuts' are hand tightened up
Make sure (as already mentioned) the caps are fully pushed onto the top of the plug, the rubber may bind first giving you the impression you've pushed them on fully.
Any break/poor connection/gap (including the worse case of a damaged inner core of the leads will cause the HT (the spark voltage) to have trouble getting the plug tip where it needs to be ... the energy will be reduced (causing a poor spark and misfire)

 

[JAMLAX]

I worked all day on this simplest of jobs. I think I'll wait till the spark plugs and HT leads arrive on Thursday. Then I can make sure the HT leads are properly secured. I have an inkling this is the problem. In any case, by the look of the HT leads they may be as ancient as the car. Patience is the thing I need right now while waiting for Royal Mail to deliver!

And indeed I was careful to replace the HT leads correctly

 

[The Panda Nut]

Always start the plugs by hand and be careful not to cross thread. If in doubt stop. I find a drop of 3 in one on the threads is almost a must. Koalar rightly points out that the plugs are in at an angle.

 

[jrkitching]

Koalar rightly points out that the plugs are in at an angle.

For which reason I find that a universal joint next to the plug socket makes removal and replacement a bit easier.

A 1/2" drive socket and extension bar doesn't quite fit straight onto the plug, due to said angle; a 3/8" drive setup might just have enough clearance.

They're easily cross threaded by the careless or hamfisted, but equally easily put in correctly if you're careful and only turn by hand until you're sure they're straight.

I do use a tool like the one in koalar's earlier picture for removing the leads; I've not damaged one yet.

 

[koalar]

For which reason I find that a universal joint next to the plug socket makes removal and replacement a bit easier.

A 1/2" drive socket and extension bar doesn't quite fit straight onto the plug, due to said angle; a 3/8" drive setup might just have enough clearance.

They're easily cross threaded by the careless or hamfisted, but equally easily put in correctly if you're careful and only turn by hand until you're sure they're straight.

I do use a tool like the one in koalar's earlier picture for removing the leads; I've not damaged one yet.

I also never had to replace a fiat OEM lead (factory fitted ones)

That's two car at 200K miles, and two other over 150k if you include a punto still on the original factory leads

 

[Mike1alike]

The very useful trick in removing the leads is to never try doing it when they/the engine are/is hot. The heat makes the silicone protections to get tightened and trying to do the job in that situation makes it impossible without damaging the leads. If you do it on cold engine (sitting overnight) they come out rather easily.
When putting the leads back, especially if using the same ones (but if they are new, too), make sure the contact inside protection (and cable) was not pulled up inside making it then to have improper contact or no contact at all when you put it on the plug. Also, make sure the contact is tight enough and dosen't sit loose on top of the plug. If it's loose it can be tightened by squeezing/pressing carefully through the silicone protection. It's good practice to first test place the leads on the plugs before putting them on the car, to notice how far down they must go and to hear the click they make when they get to sit in their place. Not having proper contact between leads and plugs gives the exact problems @JAMLAX reported having.

 

[koalar]

There appears to be some misunderstanding of what the lead on an early pandas are

These are the genuine leads, not third party rubbish

Fiat ones

The contacts in the end are moulded into a big lump

You can't squeeze by where the ribs are unless I am a wimp, that will make any difference


It makes little difference if you remove them hot or cold, unlike the plugs themselves, I do this all the time when diagnosing a driveability issues

You can not slide the boot at all, it's moulded close to the contacts

This is my spare from an engine that's done 200k, and is still fine, when I got a new coil from the breakers I took the leads with it as a spare, although not needed, as long as you pull from the ribbed part it pretty impossible to damage

Yes they can be tight to remove and push back on

I don't really think too much about it, as it normally takes seconds, I kind of wiggle twist push and pull untill they let go

 

[The Panda Nut]

There appears to be some misunderstanding of what the lead on an early pandas are

These are the genuine leads, not third party rubbish

View attachment 471024


Fiat ones

View attachment 471025

The contacts in the end are moulded into a big lump

View attachment 471026


You can't squeeze by where the ribs are unless I am a wimp, that will make any difference


It makes little difference if you remove them hot or cold, unlike the plugs themselves, I do this all the time when diagnosing a driveability issues

You can not slide the boot at all, it's moulded close to the contacts

This is my spare from an engine that's done 200k, and is still fine, when I got a new coil from the breakers I took the leads with it as a spare, although not needed, as long as you pull from the ribbed part it pretty impossible to damage

Yes they can be tight to remove and push back on

I don't really think too much about it, as it normally takes seconds, I kind of wiggle twist push and pull untill they let go

I find a lot of brute force and cut fingers makes it easy.

"Fiat; sponsors elastoplast"

 

[Mike1alike]

These are the genuine leads

Yes, those are ok and I think the cable stays put in those ones. Also, I guess I went a little too far about the contact grip, because these good leads have that little bit that keeps them round and tight, they cannot go loose. Actually, on these ones it's the other end contact, the one that goes into coil that can use to be widened a little bit if you've taken them out.
And there are also very good leads, the NGK and Magneti Marelli. NGK is like Fiat, same kind of protection and cable doesn't move. With the Magneti Marelli the cable can move up or down.
Anyways, for any lead brand, the main idea is you have to push the lead all the way in to the spark plug, until it clicks, otherwise there is no firm contact and that means trouble.

As for taking them down, all of them have silicone protection (plus plastic bits in Fiat and NGK) and it most certainly gets tightened when it heats up. They 100% come down more easy if you take them down when the engine is cold. Especially if they weren't taken down in very long time

 

[ZaphodB]

The diameter belies their toughness