The 'E' Type Forum

So I finally seemed to have fixed all of my ignition problems and had a couple of glorious weeks of stunning performance smooth and glorious.

The then yesterday it started backfiring and missing, I thought I had just put the choke in too early and pulled it out a bit again and it ran ok and eventually I put it back in and it ran ok but Still ocassionally a bit rough.

Today it won’t run properly at all even when fully warm without the choke all the way out and even then its not quite right. Violent misses and backfiring through the carbs.

What are your thoughts? I don’t know where to start.

I can't remember from your previous post what you changed. I had a similar experience where I seemed to fix things only for them to turn sour again. I think the issue was that as soon as you put in, for example, new plugs or points etc, things run great for a while because the real problem is camouflaged by the new components. I am NOT an expert, but my approach would be to change everything again, keeping the old parts as spares (they at least are known to work ro a degree in the event of breakdown).
So new points (or ignition unit), cap, coil, plugs, plug caps, rotor arm, (red one) and new leads, both king and plug leads. I'd still fit silicone leads even though others say resistor caps are the answer and almost certainly know more than me; it's just that fitting silicone leads solved my problems permanently.
Of course I imagine you've checked and ruled out fueling?

It sounds like slipped timing to me . One possible explanation could be that either the mechanical or vacuum advance mechanism has seized in the full advance position

Thanks Malcolm
I replaced plugs, leads, coil, distributor cap and rotor. It has Pertronix instead of points and original distributor. I guess if it’s electrical it must be that and Christopher may be right.


However I’m starting to suspect a sticky needle in a carb or similar

If that doesn't cure it, swap out the Petronix for points and change the coil. See if that does it.

Yes new coil, rotor arm & ignitor in dizzy.

Check timing and mixture too, sounds like you could be running lean. Is the engine running on when you switch off?

Ps. check and replace plugs too - what colour are they? Should be that nice light brown colour...

PPs. check fuel filter and pipes too - if there is any weakness/split in the pipes can cause air to leak in, reduce the pressure and starve the carbs...

Hi Andrew

It sounds like a timing problem to me. Are you sure the distributor hasn't moved? It's very easy to forget to tighten the distributor pinch bolt after setting it up.

Regards

The engine in my car had an elusive timing problem wherein the static timing would move around, particularly after blipping the throttle. I'd set it a the proper mark, blip the throttle a few times, and the static mark would move to another location. I initially thought I had failed to properly clamp the distrbiuter, but it turned out to be caused by friction from corrosion and dirt in the bearing surface between the vacuum and mechanical advance plates. Disassembled the distributer, cleaned and lubed that bearing surface and all is well.

Sorry I now have a couple of threads on this problem but for completeness of this one, I have installed a 123 Electronic distributor replacement and all going really well so far, but I have had a good result before only to have it go bad again within a few weeks so fingers crossed this has nailed it