AirSpeed VW Community Forums
General Forums => Air Speed Lounge => Topic started by: beetlemandan on March 07, 2011, 07:04:31 AM
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trying to get my gas heater working in my 69 beetle and the glow plug keeps getting wet with fuel (it won't get hot). the voltmeter says its only getting 4 volts to the glow plug. i ran 12 volts to it and the thing fired right up and worked great even after i removed the hot wire and let it soldier on with 4 volts. whats the official voltage theses things are supposed to get?
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I'm not 100% sure but I think it drops to 6v at the reducer.
Bruce may know as he is quite knowledgable in the gas heaters
As well I think Busdaddy and Dave Hord know lots as well
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It would be helpful to know which model of heater you have so we can direct you to the correct troubleshooting procedures.
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Do you have a B2 Heater:
(https://airspeedparts.com/forums/proxy.php?request=http%3A%2F%2Fi41.photobucket.com%2Falbums%2Fe283%2F55OvalCharlie%2FIMGP0268.jpg&hash=17b5ff3c978780ef5bc747fda680ec8550ca089c)
or BN2?:
(https://airspeedparts.com/forums/proxy.php?request=http%3A%2F%2Ffarm6.static.flickr.com%2F5082%2F5347722925_595734cc17_z.jpg&hash=10afb95062c05d2e779ff4d5f325f70873e94e93)
Most of my knowledge is on the BN2, but I do have a troubleshooting manual for the B2 tucked away somewhere on a hard-drive. The BN2 troubleshooting manual states that the glow plug should bright red after one minute when 4 volts is applied to the glow plug. If it does not, replace the glow plug. Sounds to me like you're shopping for a glow plug. I do have a known good one you could borrow for testing, but it belongs to a working heater so you'll need to source a permanent solution from the Samba or similar.
Once the heater fires, the glow plug is no longer heated via electricity. The heater diesels on the gasoline, turning on the Voltage only if the flame detector notices the flame has gone out.
-Dave
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Helpful Links:
http://oacdp.org/ebersp.html (http://oacdp.org/ebersp.html) - BN2 / BN4 specific.
http://www.thesamba.com/vw/forum/viewtopic.php?t=314546&start=0&postdays=0&postorder=asc&highlight=eberspacher&sid=4b8db63b26f9cd392057500cdd5ef1d1 (http://www.thesamba.com/vw/forum/viewtopic.php?t=314546&start=0&postdays=0&postorder=asc&highlight=eberspacher&sid=4b8db63b26f9cd392057500cdd5ef1d1) - B2 Rebuild, tonnes of info in here.
-Dave
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its a b2 like the picture, although mine is a little more ratty silver than the above one. i'll check to see if it glows after a minute and give an update
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The glow plug operates at 4V. They don't last long if you hit them with 12.
I think your problem is that you aren't getting full current through the plug. If you have any bad connections along the way, the current won't be enough.
Follow the wire from the glow plug along it's path through the series resistance to the terminal block to wherever you supply it with 12V. Clean up all the brass terminals. Over the years of using these heaters, I have found several times where the ΒΌ" spade connectors get weak and don't grip very well. This will limit your current. Check each flap of the connector. Many times one side will develop a crack. It will look ok, but if you just grip it with your fingernail, it will break off.
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so i checked to see if the glow plug glows a 4 volts, which it doesn't, but you can get it to ignite if you pull the switch and let it run for a few seconds then give the plug a 1/2 second shot of 12 volts.
but after reading bruces comment i think i'l be cleaning contacts and try it all over again.
thanks for all the help everyone!
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The glow plug pulls so many amps that it pulls the voltage of your battery down a bit. To start mine, I would first start the car, then hold the revs at about 2-2500 rpms so the generator is putting out a good charge. Then I'd pull the switch. Once you hear the heater fire up, you can let the revs drop, then turn on your headlights and go. If I didn't go through this procedure, the heater wouldn't fire.
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I go through the exact same process as bruce with my b2. I have an alternator.
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Yup, same here. Rev to 2k, and it fires up within 60 seconds.
Without revving it up, it's hit-or-miss if it will fire.
-Dave
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thats good to know. should sound intersting with the open stinger on right now ;D