Ahh.....Joseph Lucas, the "Prince of Darkness" rears his ugly head again!
Y'know, there's a poster on the wall in the Lucas factory. It reads "Work Hard and Get Home Before the Sun Sets". There's a
reason that's posted in the Lucas factory.
Anyone know why the English drink warm beer? Yep, it's 'cuz Joseph Lucas makes refrigerators, too.
Some of the screwiest electrical problems I've ever solved involved Lucas electrics. Scary stuff...driving down the road one night in an MGB-GT I used to own, hit a bump - all the lights went out...I mean everything...TOTAL darkness! I tried to hold the wheel straight and stomped on the brakes. Hit another bump, and everything came back on again. No problem....drove on home with no further problems. Looked for a short, loose connection, bad ground - ANYTHING - for over two weeks. Never found the problem and it never happened again. Weird.... Gremlins... Who knows...?
Had another problem with a secondary wire to the distributor. Under load the car would run fine, but if you took your foot off the throttle, the car would die - but before it would totally stop, it would rev up again and then die, then rev up again. All this without touching the throttle. Put your foot back on the throttle and start to accelerate and everything was Jake...worked fine. Take your foot off the throttle and it would die, then rev up, then die, then rev up...DROVE ME NUTS!
Turned out to be a broken wire INSIDE the insulation. It was the secondary wire that went to the ignition points. Under load, the vacuum advance would relieve the tension on the wire because the plate would move as the ignition would advance. Once the tension was relieved, the car would run just fine. But, take your foot off the gas, and the vacuum would reduce causing the plate to retard, thereby placing the wire under tension again, breaking the connection and killing the spark. Then, the plate would return as there was NO vacuum and the wire would make connection, the fires would light again, and the engine would rev up....until of course the vacuum increased to the point where the plate started to advance again and we'd begin the vicious process all over again! It would Rev up, then almost die, then rev up, then almost die. Did that for two weeks until I could find the problem. Just stumbled into it using a volt-ohm meter and checking connections. I saw the needle flicker a little while testing this wire. But, I could only make it fail when I forced the ignition to advance. I finally determined the wire was broken...removed it and confirmed it was indeed broken inside the insulation. Replaced the wire, and the problem went away.
I could have KILLED Joseph Lucas...!
It's funny NOW, but it certainly wasn't then. I lost both hair and sleep over that one...what a nightmare!