One point to add: if the test light shows pulsing power to the coil, and your ignition system uses points (e. g. non-electronic), before writing off the coil, test the condenser (by meter or by substitution). Without a good condenser, you cannot mechanically break the coil power fast enough to keep all of the coil energy from being dissipated in an arc at the points. [Obviously, electronic ignitions don't suffer from this problem, as transistors can switch off in nanoseconds.]
Note: DO NOT routinely replace condensers, as the new production units seem to be of rather poor quality.
Testing the Ignition System No Spark
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telforddorr
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Re: Testing the Ignition System No Spark
For more VW electrical, see http://telforddorr.com/ (available 9:00am to 9:00pm, PST)
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david58
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Re: Testing the Ignition System No Spark
I know if you put this up here for a couple years and nobody answered it the detailed instructions apply to a negative ground system I am not sure how to test for a positive ground system I will see what I can find out and post it up
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david58
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Re: Testing the Ignition System No Spark
Okay I didn't find any information on a positive ground system
But I can tell you how to test it. Instead of hooking the test light to the ground side of the battery hook it to the positive side of the battery. Your still using the test light on the negative side of the battery.
I hope this helps to simplify how to test your positive ground system.
But I can tell you how to test it. Instead of hooking the test light to the ground side of the battery hook it to the positive side of the battery. Your still using the test light on the negative side of the battery.
I hope this helps to simplify how to test your positive ground system.
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Ol'fogasaurus
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Re: Testing the Ignition System No Spark
I'd check the test light first to be sure it is working correctly.
If you can't see the way the battery is hooked up, one way to check for positive or negative grounded vehicle system is to put one of the test lights wires on the battery's ground then touch the positive part of the pan or object's wire you are concerned about using the other test light's wire. If the light goes on, then you should have a positive ground system.
No light up, then check for positive ground system using the reverse of the above to check.
A volt OHM meter or other type of system check meter you might have would be about the same way.
This is basically simple unless... of course the light does not go on either way
.
Lee
If you can't see the way the battery is hooked up, one way to check for positive or negative grounded vehicle system is to put one of the test lights wires on the battery's ground then touch the positive part of the pan or object's wire you are concerned about using the other test light's wire. If the light goes on, then you should have a positive ground system.
No light up, then check for positive ground system using the reverse of the above to check.
A volt OHM meter or other type of system check meter you might have would be about the same way.
This is basically simple unless... of course the light does not go on either way
.Lee
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Ol'fogasaurus
- Posts: 17760
- Joined: Mon Nov 13, 2006 10:17 pm
Re: Testing the Ignition System No Spark
One other thing to check is the condition of the woven ground strap as they have a tendency to limit their ability to work correctly due to age and internal problems (braided wires breaking for an example]. They go way back in use and age so they can start to fail to do their job well. Quite often it is enough broken strands that allow a positive check but when it comes to hard work then they can fail.
Their use in new cars started to go away in the early to mid 50's here in the states but some other companies in other countries continued to use them. I'm not sure when VW stopped using them, but the bugs (if I remember correctly) used them for the backup grounding of the body on the pan (remember... there is a gasket between the pan and the body, add to that, the fasteners are contacting painted surfaces fastener head top [body] and nut and washer below [pan]). The strap went to the casting for the shocks using the body bolt on it (on the passenger side if I remember correctly).
Lee
Their use in new cars started to go away in the early to mid 50's here in the states but some other companies in other countries continued to use them. I'm not sure when VW stopped using them, but the bugs (if I remember correctly) used them for the backup grounding of the body on the pan (remember... there is a gasket between the pan and the body, add to that, the fasteners are contacting painted surfaces fastener head top [body] and nut and washer below [pan]). The strap went to the casting for the shocks using the body bolt on it (on the passenger side if I remember correctly).
Lee