Voltage too much for glow plugs?

Technical questions and answers about the Mazda Bongo

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mechanik

Voltage too much for glow plugs?

Post by mechanik » Tue Nov 13, 2007 6:29 pm

This forum is brilliant, so quick and helpful, a big THANK YOU to everyone :D The problem is a starting one listed under "my mechanik is at a loss" below. Well, he has checked the relay and it works but he thinks that the glow plugs are blowing because they get 12volts to them and should only be getting 10volts, therefore he is looking for a faulty 'voltage regulator'. Is the system that voltage critical? and where would that regulator be?
Thanks again
Michael
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mikeonb4c
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Post by mikeonb4c » Tue Nov 13, 2007 6:34 pm

Sounds a bit unlikely to me. Cant remember the history of this discussion, but are you confident you havethe right length glowplugs in (compare teh new ones with the old).

Hopefully someone more knowledgeable than me will be along to comment shortly

Mike 8)
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dandywarhol
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Post by dandywarhol » Tue Nov 13, 2007 7:20 pm

I think your mechanic is talking pi55. Why would you only put 10 volts into a glowplug when you can use full battery voltage and create more heat :?:

If cheap plugs are used they'll pack in early - you gets what you paid for.

Get a set of NGK plugs - see here: http://www.igmaynard.co.uk/bongo/forum/ ... hlight=ngk
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Ralph

Post by Ralph » Tue Nov 13, 2007 8:26 pm

If the plugs are working you may get a voltage reading of 10 volts
due to voltage drop they draw lots of amps but if they have burnt
out so not drawing current I would expect to see battery voltage
on the bar when the glow light is on.
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Post by daveblueozzie » Tue Nov 13, 2007 9:52 pm

As Mike has said make sure you get the right size glow plug as well. a lot of people do not know there are two sizes for the glow plugs.
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smartmonkey

Post by smartmonkey » Wed Nov 14, 2007 1:51 pm

All glow plugs are meant to work at battery voltage. They may drop below 12V but only because of the high load. If the wrong plugs went in the last time you may have a short to earth somewhere because the supply is too close to the cylinder head. This may well fry the relay. You can test plugs by connecting them to a battery and watching them glow cherry red. They should heat up very quickly and glow for about half an inch. Test the relay by taking a heavy duty feed from the battery direct to the plug rail and give them 10 seconds then if it fires up OK you may have a supply fault.
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Post by scanner » Wed Nov 14, 2007 4:19 pm

Bongo plugs are variously shown as 11 or 12volt but that difference in negligible in use.
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