Hey guys back again!

got round to my servicing.

however engine managment light is on, all ht coils and leads are in sequence, all are correctly on and connected.

car back fires and mis fires like anything it's boardaline drivable (defo not driving it anywhere until car is sorted though)

punto revs fine without mis firing so it's no cyliner head?

i'm stumped ona job so easy it's gone so wrong!

any questions fire away, thanks alot all!

What engine?

Why does one sentence suggest missfiring, the other that it revs fine?

Cheers

SPD

it's a 1.2 8v.

heavy movement/vibration in the car and in the engine bay from air box for the mis firing.

just doesn't run right, very un smooth plus managment light is on.

one of the old spark plugs had some oil on it, apart from that cant think of much more info to give out unless more questions are asked.

thanks

What order have you put the plug leads on the coil packs?

Cheers

SPD

i only replaced 1 lead at a time with the correct length from the new set.

goin to put the old spark plugs back in tonight so at least i can drive. think one of the new spark plugs may b faulty?

Did you check the gap on them? Should have a 0.8mm gap on the spark plugs on that engine.

If the only things disturbed were the coils and leads then the fault is 99% around there somewhere. Maybe they are the worng type leads.

These engines have a wasted spark and no ditributor, so if any leads are swapped over, the engine will missfire badly.

MAJOR EDIT: I got it wrong, car does misfire when revving.

@whitesei: the leads were all fine before i changed the spark plugs.

just put old plugs back on and engine managment is still on. Any suggestions now?

p.s why can'ti edit original post?

If you have had a missfire, then there will be unburnt fuel in the exhaust which the O2 sensor(s) will see, hence the management light on.

If the missfire has now gone, drive around for a bit until the fuel is all burnt off.

Cheers

SPD

rallycinq said:

If you have had a missfire, then there will be unburnt fuel in the exhaust which the O2 sensor(s) will see, hence the management light on.

If the missfire has now gone, drive around for a bit until the fuel is all burnt off.

Cheers

SPD

Click to expand...

sorry should of been more specific. Missfire is still present.

I really don't understand it, why don't the old plugs work ?because they are defo the right electrode gap, admitadly, with my new plugs, the gap is not 0.8 it is smaller. Completely my mistake but have i messed my car up by putting a different electrode gap in there with the new plugs??

With the engine running, remove and replace one plug lead at a time, to find the one or more that aren't firing.

Report back

Cheers

SPD

rallycinq said:

With the engine running, remove and replace one plug lead at a time, to find the one or more that aren't firing.

Report back

Cheers

SPD

Click to expand...

how do i hold the leads without reciving 12v's in my system? tried this before

thanks

SoulPower said:

how do i hold the leads without reciving 12v's in my system? tried this before

thanks

Click to expand...

It ain't 12V, its more like 20,000V. Use insulated pliers.

Cheers

SPD

When engine is running that is? bad times.

Also just to ensure? where is the ht lead numbering on the coil pack? and if i'm looking at the engine bay, which spark plug is numbered as 1? far left hand side nearset oil dipstick

thanks alot

You will probably have two coil packs. One for plugs 2 and 3, the other for 1 and 4.

Number 1 is furthest from the gear box.

Yup, engine running. When you remove a lead the engine will either run worse, so you know thats not the faulty one, or, there will be no change to how the engine is running, then thats a faulty one.

That assumes you have the plug leads on the right way round on the coils, so revisit that first.

Cheers

SPD

Hi

having a similar issue to this but seems to be intermittent, It will be driving fine then suddenly loose power the EM light comes on and there is a lot of vibration and movement , it will then kick back in again

I don't know a lot about cars or engines but could this be a loose connection on a plug lead or a faulty plug lead?

Thanks

Wyarn said:

I don't know a lot about cars or engines but could this be a loose connection on a plug lead or a faulty plug lead?

Thanks

Click to expand...

Short answer, yes, either is possible. Could also be a coil pack on the way down.

Cheers

SPD

rallycinq said:

You will probably have two coil packs. One for plugs 2 and 3, the other for 1 and 4.

Number 1 is furthest from the gear box.

Yup, engine running. When you remove a lead the engine will either run worse, so you know thats not the faulty one, or, there will be no change to how the engine is running, then thats a faulty one.

That assumes you have the plug leads on the right way round on the coils, so revisit that first.

Cheers

SPD

Click to expand...

new update; let a friend look at my car while i was at work, changed spark plugs and swapped leads round, car will not start now, seems like battery is flat but cannot be started with jump leads.

Battery is gone??

I might try pulling one spark plug out at a time with the ht coils attached and see if they spark?

The engine uses a wasted spark so put one coil is on 2 and 3 and the other on 1 and 4. If it wont run swap the coils over.

Missfires happen when the plugs are old or plug leads or coils are faulty. Though of course lots of other stuff can make an engine run rough.

Gap on Bosch spark plugs should be 0.8mm
Gap on NGK spark plugs are 0.9mm
Thats according to Haynes.

Also battery is not gone if you can't jump start the car either. You can jump a car with no battery.

Can someone please give a wiring sequence for the plugs and leads to the coils please. Was changing my spark plugs and leads over and number one punto was wired differently that number two punto! Although both cars run fine wired each way! :s which confused me!

Car number one has always been slow and unresponsive to the accelerator for a second or 2. Whereas punto number 2 is faster and more responsive yet slightly rough at low speeds but otherwise really smooth.

Just wanted to know the correct wiring order