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I have a 10/2000 My 2001 MGF the car has done 123,000km.
The engine will not start normally and when I do get it to start by checking the wiring for lose conections etc, the engine has a bad misfire.
A new cam angle sensor and NGK PFR6G-11 spark plugs were fitted at 57,000km and I have just fitted 2 new HT leads, when it is running I can hear a ticking sound from the no 1 coil pack and in the dark I could see a spark arking to earth, so I decide to swop coil packs 1 to 3 and 3 to 1 for something to do, it stopped the arking and misfire but when the engine cools down or the next morning it will not start again, it's a complete mistery to me and I need some expert advise.
Thanks Cartoys

I'm no mechanic, but depending where you live, I use Brian at Link Automotive in Mitcham to solve ny problems. Touch wood I have never had your experiance.

Moved your post to the Technical area where hopefully you should get more feedback on the subject

The coils should not be arcing, so I suspect that this is the clue to the problem with the ignition circuit. Is a coil pack failing?

Which HT leads have been replaced?

Rob Bell wrote:The coils should not be arcing, so I suspect that this is the clue to the problem with the ignition circuit. Is a coil pack failing?

Which HT leads have been replaced?

I have replaced a new coil pack that I thought was arcing and I have fitted another new cam shaft sensor also 2 new HT leads one from no 1 cyl coil to cyl no 4 and one from cyl no 3 coil to cyl no 2 and 4 new NGK PFR6G-11 spark plugs the parts change seam to have improved the misfire but I am still getting bad starting from an engine cooldown or especially from a fresh overnight start.
When I first crank the engine it turns over freely, on the second crank it fires intermitantly, if I keep on cranking it eventually starts, once it has started and settles down and the engine warms up it starts up again every time and runs smoothly without any problems.
I have disconnected many wiring harness plugs and sprayed them with CO contact cleaner including the 2 large plugs on the CPU nothing I seam to do will correct the bad starting problem.
I got a tip to check the inertia fuel cut-off switch, for some reason it needed resetting, when i pressed the rubber top there was a click that indicated it had reset, yet fuel was still being supplied to the engine before the reset, as I drove the car home when I bought it.

Cartoys frustrated!! you would't belive, any of you had this kind of problem?

Your symptoms are not identical but have some similarities with an electrical issue reported here recently. It seemed to improve the starting/running when all the cabin fuses except 14 and 19 were removed, which pointed to a short circuit somewhere that was causing interference with the LT circuits. The exact cause is as yet unknown, but perhaps worth you trying the same. The coil arcing seems to indicate that it's still receiving power and is in communication with the ECU, but something else is corrupting the process.

If you've not already, a clean-up of the earth strap on the battery and the earth point on the rear firewall might prove beneficial - the initial refusal to start and then gradual improvement & finally running ok does sound typical of a bad connection.

Would concur that it appears to be a current/voltage problem. If not connections then I would suggest getting to work with a voltmeter starting with the battery when cranking.
Geoff F.

Bandit wrote:Your symptoms are not identical but have some similarities with an electrical issue reported here recently. It seemed to improve the starting/running when all the cabin fuses except 14 and 19 were removed, which pointed to a short circuit somewhere that was causing interference with the LT circuits. The exact cause is as yet unknown, but perhaps worth you trying the same. The coil arcing seems to indicate that it's still receiving power and is in communication with the ECU, but something else is corrupting the process.
If you've not already, a clean-up of the earth strap on the battery and the earth point on the rear firewall might prove beneficial - the initial refusal to start and then gradual improvement & finally running ok does sound typical of a bad connection.

I am about to try your first suggestion need clarification of cabin fuses though, except 14 I can understand but 19 is heater blower, I would have thought it would have to be 24 Starter, I am going to give it a go tonight as its 32 deg's in the sun so I will wait untill it cools down tonight.
I have cleaned the earthing points yesterday battery and engine + firewall and the battery condition was checked by the RAA road service, battery ok, starting problem no change. cartoys.

Possible there's a different fuse layout depending on spec (aircon etc) & model (pre & post 2000), 24 is commonly the blower and 19 the engine management (MEMS ECU). But yes, pull out 19 if that says Blower & leave in anything marked Starter or ECU/MEMS

The most common wiring loom issue is the flexing section between the rear bulkhead and the bootlid, and whilst it might not seem logical it could affect proper running there may be merit in opening up the plastic sheath around the section that flexes when the boot is opened & closed, and see if there are any broken or frayed wires there. There is a little too much tension in the factory install, so when a wire does break the ends can be 10cm or more away from each other. Even if you discover nothing is currently frayed or fractured, splicing in some extra wire to relieve the tension is highly recommended, prevention being better than cure

Bandit wrote:Possible there's a different fuse layout depending on spec (aircon etc) & model (pre & post 2000), 24 is commonly the blower and 19 the engine management (MEMS ECU). But yes, pull out 19 if that says Blower & leave in anything marked Starter or ECU/MEMS

The most common wiring loom issue is the flexing section between the rear bulkhead and the bootlid, and whilst it might not seem logical it could affect proper running there may be merit in opening up the plastic sheath around the section that flexes when the boot is opened & closed, and see if there are any broken or frayed wires there. There is a little too much tension in the factory install, so when a wire does break the ends can be 10cm or more away from each other. Even if you discover nothing is currently frayed or fractured, splicing in some extra wire to relieve the tension is highly recommended, prevention being better than cure

I removed all fuses except for 14 Engine management System and 24 Starter, based on post 08/2000 MY2001 MKII CVT Auto A/C MGF, no change on bad starting.
Then I reverted to your second suggestion, with the boot lid closed the engine would not start, with the boot open the car started normaly.
I found 1 broken grey/red stripe wire and 2 badly frayed wires, 1 the same colour as the broken one and a black one.
Repaired all wires and removed the lower loom clip to relieve tension, unfortunatly this doesn't seem to have fully resolved my problem, it's worth mentioning there still could be a wiring problem as I have discovered that after arming and disarming the car it starts normaly.
Thanks anymore clues would be very much appreciated. cartoys

How far back did you strip the plastic sheath? The + of the 10+cm can easily be underestimated - once a wire is broken and free to move, each time you open and close the boot it can be working its way down the plastic sheath, contacting who knows what on the way... If you have any broken ends of wires that you couldn't find a corresponding coloured wire to re-connect them to, widen your search - it'll be there somewhere. Adding a 10cm length to all the wires that haven't yet suffered is generally a good plan, removing the clip does help but adding slack is a more reliable solution/prevention.