Spluttering engine when hot

[Davektm]

Hi guys,

My 72 F100 390ci has started spluttering and firing erratically when driving once warm, I fear it is an ignition problem as it also seems to be charging at up to 16v which it didn't do before I changed the battery cables for new ones and fitted a new starter and solenoid. I think the voltage regulator is bad. Is it likely this could have damaged the coil or any other ignition components? I am planning to change the VR, condenser and coil to try and solve the problem. Any experience of this or advice would be much appreciated. It also has an MSD ignition but still has points which are set correctly.

Thanks, Davie in Scotland

[Lee]

Hi,

I think you are on the right path with the items you listed to replace.

I have heard of coils internally arching when hot so maybe this is your problem. Also, 16volts is high so I would change the VR as you suggested.

Lee

[Davektm]

Well coil, VR and condenser changed and she is still spluttering when hot. I'm sure it's electrical because when it splutters the rev counters drops by half even though engine revs don't drop by half. Any ideas?

[tac]

If the REV counter (Tachometer?) is the type that that connects to the coil you might try disconnecting it. I've seen them go bad and start shorting out the coil.

How hot can it get there?

[Davektm]

It's a Dakota dash and rev counter running off the msd ignition. Hot? Haha not very especially this summer, probably been about 25 degrees C this year!

[Davektm]

I found the problem, wiring harness had been burnt by the exhaust and was arcing on the block