Technical HT leads

[Adam1984]

Hello,

Regarding the HT leads replacement for my car.

I have heard that my car has a wasted spark plug principle, which means that the HT leads can be connected just 1-4 in normal order.

Why have I seen elsewhere that they need to go in a different specific order?

Does anyone know the right way please? It's a 1.2 petrol engine (2015)

This picture attached is the way my mechanic friend fitted them.

Thanks

 

[Eltezz]

I can’t see all of the plug leads but they look ok. More important, did the car start and run the same as before the new ones were fitted? If so, stop worrying about them. All is well…

 

[Adam1984]

I can’t see all of the plug leads but they look ok. More important, did the car start and run the same as before the new ones were fitted? If so, stop worrying about them. All is well…

Yes

Car runs and feels the same. Did a clean up of the VVT sensor and Map sensor.

But am still getting a rough idle and poor acceleration.

Just didn't know if the leads have to be in a certain order. If anyone has the same engine as me, if possible can you take a picture of yours please?

 

[Eltezz]

Adam, I won’t say this again - if the car is running ok, the leads are in the correct order. Basically, the left lead goes to the left cylinder, the next lead to the next cylinder and so on. If you are still experiencing rough running then you need to look elsewhere.

 

[Herts Hillhopper]

If in the wrong order (1) the engine will likely not run and (2) almost certainly an error light will show. Also, I think any mechanic worthy of that title would likely be offended by someone else suggesting they mixed up the plug leads.

Your car is working. Have you compared it with another similar Fiat to see if ‘they are all like that’? What’s the option of your mechanic? How does your other car (the Citroen) run…?

 

[Adam1984]

If in the wrong order (1) the engine will likely not run and (2) almost certainly an error light will show. Also, I think any mechanic worthy of that title would likely be offended by someone else suggesting they mixed up the plug leads.

Your car is working. Have you compared it with another similar Fiat to see if ‘they are all like that’? What’s the option of your mechanic? How does your other car (the Citroen) run…?

I don't know anyone else with the same fiat as me, I was hoping someone on here could send me a picture of theirs so I could see.

The Citroen runs really well thank you.

 

[Herts Hillhopper]

We know from previous posts that you have detected an uneven idle. You have since replaced the (nearly new) spark plugs, and the leads to them - but still detect an uneven idle. That suggests the cause of unevenness is not the plugs or the leads.

 

[Adam1984]

We know from previous posts that you have detected an uneven idle. You have since replaced the (nearly new) spark plugs, and the leads to them - but still detect an uneven idle. That suggests the cause of unevenness is not the plugs or the leads.

I know and thank you.

I literally have no other idea what it could be now.

 

[Herts Hillhopper]

I don't know anyone else with the same fiat as me, I was hoping someone on here could send me a picture of theirs so I could see.

The Citroen runs really well thank you.

On the later Panda (like yours) the leads come from the coils in the same order as the cylinders (1-1,2-2,3-3 and 4-4). That is not the order they are triggered in though - the electronics fire the coils in the order 1,3,4, 2

 

[Adam1984]

On the later Panda (like yours) the leads come from the coils in the same order as the cylinders (1-1,2-2,3-3 and 4-4). That is not the order they are triggered in though - the electronics fire the coils in the order 1,3,4, 2

Oh so the cables from the coil pack from 1-1, 2-2, 3-3 and 4-4 are ok on my fiat?

 

[Herts Hillhopper]

I know and thank you.

I literally have no other idea what it could be now.

The reason I asked about the other car was to see if you were happy with how that ’felt’. That gives us (the readers here) the reassurance that you ‘know the difference’ (if I can put it that way) between a good and bad engine. You do. Good.

The trouble is, we (the readers and responders here) also have no other answers to give. It’s a long time since I had a Panda with the 1.2 engine, and in its 2005 guise it was a much ‘simpler’ engine anyway.

As to comparing with another car, what’s the view of your mechanic(s), who are likely to have worked on that engine in other cars? Have they test-driven your car? Are they happy with the way yours feels, compared to others they’ve driven?

 

[Herts Hillhopper]

Oh so the cables from the coil pack from 1-1, 2-2, 3-3 and 4-4 are ok on my fiat?

Correct. And the same as @Eltezz said earlier in this thread.

 

[Adam1984]

The reason I asked about the other car was to see if you were happy with how that ’felt’. That gives us (the readers here) the reassurance that you ‘know the difference’ (if I can put it that way) between a good and bad engine. You do. Good.

The trouble is, we (the readers and responders here) also have no other answers to give. It’s a long time since I had a Panda with the 1.2 engine, and in its 2005 guise it was a much ‘simpler’ engine anyway.

As to comparing with another car, what’s the view of your mechanic(s), who are likely to have worked on that engine in other cars? Have they test-driven your car? Are they happy with the way yours feels, compared to others they’ve driven?

To be honest. Out of the mechanics who have looked at my car, not one of them has even test drove it.

One looked at the front brakes and didn't even take the tyres off to look.

 

[Herts Hillhopper]

To be honest. Out of the mechanics who have looked at my car, not one of them has even test drove it.

One looked at the front brakes and didn't even take the tyres off to look.

We’ve said this before too…
Time to find a decent mechanic in that case!!

 

[Panda IIs]

Hello,

Regarding the HT leads replacement for my car.

I have heard that my car has a wasted spark plug principle, which means that the HT leads can be connected just 1-4 in normal order.

Why have I seen elsewhere that they need to go in a different specific order?

Does anyone know the right way please? It's a 1.2 petrol engine (2015)

This picture attached is the way my mechanic friend fitted them.

Thanks

I've never owned a 1.2 FIRE engined FIAT but, frankly, those leads don't look long enough to reach any other plugs which leads me to think they are placed correctly.

I think you are referencing information relating to older engine technology that used a mechanical distributor where the firing order was determined by the mechanically driven ignition system, the correct placing of the lead was essential - mixing the position would lose two cylinders, the car might start but would certainly sound and drive (if it drove) horribly.

Lost spark references the fact that the plugs "fire" or spark on both the exhaust and compression cycle; the coils are triggered every full revolution of the crank.

 

[Eltezz]

Adam, to give you a bit of an idea, I have owned and driven every engine type on the MK4 Panda. Below is a short description of my thoughts on how each one feels to drive:

1.3 Multijet diesel - Very smooth and moderately noisy, plenty of low end torque, good amount of power, not too keen on revving highly.
0.9 TwinAir - Noisy and a bit frantic, loads of bottom end torque, most power apart from the later 95HP diesel, not keen on revving highly.
1.2 FIRE - Super smooth and quiet, lacking in bottom end, least power of all and the slowest, loves to rev.
Hybrid thing - Gutless and couldn't wait to give it back, as slow as the 1.2 but not as smooth.

In short, your 1.2 should be a nice smooth quiet engine but the car will be slow and feel underpowered.

Please bear in mind these are my opinions and others may disagree...

 

[Panda IIs]

Adam, to give you a bit of an idea, I have owned and driven every engine type on the MK4 Panda. Below is a short description of my thoughts on how each one feels to drive:

1.3 Multijet diesel - Very smooth and moderately noisy, plenty of low end torque, good amount of power, not too keen on revving highly.
0.9 TwinAir - Noisy and a bit frantic, loads of bottom end torque, most power apart from the later 95HP diesel, not keen on revving highly.
1.2 FIRE - Super smooth and quiet, lacking in bottom end, least power of all and the slowest, loves to rev.
Hybrid thing - Gutless and couldn't wait to give it back, as slow as the 1.2 but not as smooth.

In short, your 1.2 should be a nice smooth quiet engine but the car will be slow and feel underpowered.

Please bear in mind these are my opinions and others may disagree...

A slight tongue-in-cheek disagreement on the TA front @Eltezz I would say the TA loves to rev, so easy to exercise the rev limiter in my experience. Of course the power and torque has long since left the chat though! I remain amazed at the power delivery of the TA.

Otherwise yours seems like a pretty good summary