Missfire when Cold

[David Maddern]

Can anyone help me with this very annoying problem with the car. When the engine is cold, I.E left overnight, it has a very annoying misfire, almost running on maybe 6 or 7 cylinders.
The engine has recently been rebuilt about 3000 mile, the carbs have been totally rebuilt, new jets and diaphragms, new lluminition, new coil, new leads, new plugs new ballast resister, new dizzy cap, new fuel pump and it has been total tuned. The misfire lasts for about 10 to 15 minutes until the running temperature gets up to about 70 degrees and the misfire completely vanishes, the car runs like a dream, silky smooth with plenty of power.
I have noticed that when the car is misfiring, the rev counter jumps around all over the place and smoothes out when the car is up to temp. I am at a loss as what this could be, can anyone help me, please.
David

[v8wgm]

Condensation build up in the distributor cap?

[mallardstag]

Only one choke operating?

[V Mad]

Condensation build up in the distributor cap?

This can be a real problen; worth checking.

If rev counter is playing up when misfire occurs it definitely points to an ignition problem.

[Richard Saunders]

I have the exact same problem. It's driving me MENTAL! New plugs, leads, distributor cap. I'm thinking it has to be something to do with the electronic ignition, question is - which bit?

[David Maddern]

I have tried the dizzy cap for condensation when cold and before I start it, it all looks very dry in there, I have just come back from a run and as soon as the temp gets to about 80 degrees, it's as though it's a different car, up to then it is a dog, but still the rev counter is not stable until the engine gets up to temp, it has to be electrical. It is driving me mad. Can anyone help.......please.
David

[nib]

My car is much the same untill it gets to normal temp,im running on the twin points set up,I tend to think its a carb problem opposed to electrical as electrical would be making the car misfire even when up to temp.
When I first got my car it would misfire even when up to temp which made my Mk1 tacho jump about,it turned out that my car would not run smooth on NGK plugs,put a set of Champions in and it solved the problem.
There is something called a temp compensator on the carbs,I wonder if this has anything to do with it.My carbs are the early version makes me wonder why they changed over the course of production or was it US emissions linked?
Mark

[Stagdad]

You could try pulling each ht lead off when its running cold and seeing if any of the plugs are not pulling their weight,to try and determaning if it is fuel or spark.Use an insulated glove though.

Cheers Steve

[KOY 23]

You could try pulling each ht lead off when its running cold and seeing if any of the plugs are not pulling their weight,to try and determaning if it is fuel or spark.Use an insulated glove though.

Cheers Steve

And don't lean against the wing unless you have rubber underpants. Earthing via your dick is not funny.

[marcusclive]

And don't lean against the wing unless you have rubber underpants. Earthing via your dick is not funny.

It is for someone else.