Topic

Just a quickie on replacing the HT (Ignition leads) on a VVC,

There wasnt a "how to" i could see so thought i would write a quick one as ive just done mine.

My car is a MK1 '99 VVC MGF

Ensure the leads you get are for a VVC as the MPi ones arent long enough, i had to send 3 sets back before i managed to get the right ones.

Remove engine bay cover and fold the back bow up to gain access,





remove the Rover piece of plastic using the two screws at each end to reveal the 4 HT leads, i replaced the spark plugs too while i was here which need a 16mm socket bit.

Pull each lead out one at a time, replace the one you remove before moving onto the next one!!

Now open the boot and remove the inspection cover, standing at the boot use a torch and look down and just to the right to see where the leads connect. The leads are fed around the engine bay so you will need to wiggle and jiggle them to get them free and around the pipes and such. i have long arms and had no problem at all removing the old ones and putting the new ones in from the top, some people jack the car up and go underneath but its really not that hard to do it from the top.

ensure the leads are out of the way and tucked away when replacing them back around the pipes and wires of the engine bay, also ensure they are well fitted.

And thats it really, do one at a time and ensure a tight fit. Start the car to check for lumpy running (if this happens you have a fault) and if all is well put it all back together again. This may also be a good time to replace the air filter as you have it all in bits and for the sake of a fiver, its worth doing.

For those who make a mistake here are the lead positions for you.

Hmmm, numbers arent very clear so...

top pic goes

1
2
3
4

bottom pic goes

4 1 3 2

That's SO helpful, thanks! But my feeble brain can't see how that relates to a spark plug firing order of 1,4,3,2. Unless the coils provide sparks in their order (from L to R) of 2,4,3,1. But where's the logic in that? (I need to rest now...)

This may help.
There are only two coilpacks, which are energised alternatively, so the plugs always fire in pairs.

The so-called 'wasted spark' system.

On each firing only one plug is firing into a combustible mixture and the second spark is 'wasted'.

Firing order is 1342.

Coil A fires 4 & 1
Coil B fires 2 & 3
Coil A fires 1 & 4
Coil B fires 3 & 2

BTW, in the original posting, the plug firing order is 180 degrees out. On all Rover K-series engines, No 1 is at the cambelt end, not as shown in the picture. In other words, the plugs in the picture, top-to-bottom, should read:
4
3
2
1

Thanks, David. BTW, this is important!. In the original posting, the plug firing order is 180 degrees out. On all Rover K-series engines, No 1 is at the cambelt end, not as shown in the picture. In other words, the plugs in the picture, top-to-bottom, should read:
4
3
2
1

The logic of the 'wasted spark' system is presumably that both terminals 'fire' at the same time. If that is the case, it's presumably not written in stone that the HT leads are connected to the coil packs terminals in the order of 4,1,3,2.
If all the discharges ('wasted' and 'used') are equal, it shouldn't matter which way round they go as long as plug leads 1 + 4 are on the LH coil and 2 + 3 are on the RH coil.

I can't see anything in any of the MG Rover manuals that deals with this. Does anyone know of anything I'm missing?