checking dwell

[pop.pop1955]

I just replaced pts. cond. cap and rotor on my 71 super beetle. I wanted to check the dwell and timing. however when I hook up the timing light/ dwell meter the car stalls. If I hook it up and try to start the car it won't start. Otherwise the car runs and sounds good. Any thoughts?
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let your conscious be your guide

[Cusser]

[cletus_zuber]

This side of the road method works great.
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1972 1302
HPMX 40's & 019

[Cusser]

OMG - typed on a real typewriter !!!!
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1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297

[ashman40]

You need to describe how you have your light/meter connected. I suspect one of two issues:

1) The meter is grounding the #1 (-) terminal of the ignition coil. This would prevent the coil from firing. This is probably and indicator of a bad meter.

2) You are powering your light/meter from the ignition coil #15 (+) terminal. While this may be the most convenient point to get 12v+ From, any additional devices connected here take current away from the ignition coil. Over time the wire to the ignition coil increases internal resistance and limits the current that will make it to the ignition coil. All the devices connected to the #15 terminal must share this limited amount of current.
This used to happen on my old ‘75. Engine would run but as soon as I triggered the timing light you would hear the rpms drop and eventually the engine would die. This was the timing light pulling current away from the coil and weakening the spark that made it to the spark plugs.

Try a different power source for the timing light. If you have an alternator, the B+ terminal is the same as connecting to the battery + terminal. Worse case, use your battery jumper cables to extend the battery terminals to the engine compartment where you can connect the timing light to the other end.
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AshMan40
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'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!}

[BMFBMF]

In the motorcycle world one always uses a second battery to power the timing light. There are too many potential problematic interactions.

[ashman40]

[raydog]

Yes, direct from the battery is the best and easiest source for power. With my VW, I have always tapped power at the D+ generator terminal or the 12v source at the coil. Any downfall to doing it this way? Although I did get whacked twice with ignition voltage that sent me on my ass. I chalked it up to being a metal timing light with a bad ground. I still have a small scar on my knee from when I hit the curb.
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Come on, It's not rocket science. KISS

[ashman40]