TheSamba.com :: View topic

Mon Oct 24, 2016 9:35 am

I installed some new headlights on a 6volt 58' bug.
Now when driving with the headlights on, it feels like there is no power, like the distributor is not advancing.
I measured the voltage at the coil, at idle with the headlights off its 6.2 volts, with headlights on its 5.8.
I'm going to clean up the connections at the headlight switch as the power to the coil travels through it.
When does low voltage or current start to affect the coil? And a what voltage does the idiot light start to glow or come on?

I'm hoping someone had the same problem and did X. :-)

Mon Oct 24, 2016 9:51 am

What voltage do you get with the engine running at 1500-2000 rpm? (headlights on and headlights off)
Check all your grounds, including the battery and tranny straps.

Tue Oct 25, 2016 11:12 am

KTPhil wrote: What voltage do you get with the engine running at 1500-2000 rpm? (headlights on and headlights off)
Check all your grounds, including the battery and tranny straps.

well, I checked out the voltage.

6.3 v -> at battery engine off
7-8 v -> engine running 1500-3500 rpm
6.4 v -> at coil engine idle
6 v -> at coil with headlights on

while the wiring is not ideal in the car, the battery and charging seem healthy.
I cleaned up contacts and so forth and...

I DOUBLE checked my timing, it was off , corrected that and the problem went away.

Tue Oct 25, 2016 11:30 am

Those voltages should be fine. I suspect you have an iffy ignition system that wants as high a voltage as you can muster. Changing the timing helped, but I suspect it is still iffy. Check plug wire and connector resistance, and check your points and rotor for wear. Use a spare plug grounded to the case, pull a wire and connect it to the plug, crank the engine by hand and to see how bright a spark you get.