[Jay74gtv]

My 74 GTV starts and runs perfectly when it’s dry but as soon as it gets damp or rainy it won’t start. As soon as the sun comes out it starts no problem.
Any advise ?

 

[Gubi]

Check spark when this happens, maybe moisture in the distributor cap or somewhere else in the ignition system, or old worn out plug wires.

 

[Jay74gtv]

Check spark when this happens, maybe moisture in the distributor cap or somewhere else in the ignition system, or old worn out plug wires.

Will give it a try, pull off the distributor cap and spray ?
thank you

 

[Gubi]

I’d suggest an inline spark tester, see if you have spark and how it looks first. If spark is absent or weak, troubleshoot from there.

 

[alfaloco]

And do the coil as well, inside the cable where it plugs into the top of the coil. WD-40 is a water dispersant. I always kept a small can around when I messed around with any old car with Lucas ignition. I even had to use it with one of my old Mk 1 Cortinas.

 

[Alfajay]

My guess is that your coil and distributor cap are OK. I'd begin with the wires (as Gubi mentions). If your ignition wires are old, their internal resistance has increased; that combined with moisture results in shorting. Wires are relatively cheap and easy to replace. My local brand is Kingsborne: https://www.kingsbornewires.com/SearchResults.asp?Cat=1833

 

[Gordon Raymond]

All good advice. In college I had one of those 1940 Ford shaped Volvo's that even in mild humidity or the future prediction of rain or snow, made it a non-starter. I called it "Olaf-the-Lazy" and did all the above without ever coming up with a 100% fix. Be sure to post your fix when discovered!

 

[AAlfa]

Could be an arcing coil.

 

[alfaloco]

Could be an arcing coil.

Yes-- I've seen that happen, and I mean literally. Start the engine and then turn out the lights in the garage, or start it outdoors at night. Very obvious. Good way to locate leaking old spark plug leads, too.