Saab 9.3 Diesel glow plugs

Hi all

Sons Car has the GM 2.2 litre engine

Difficult starting on cold mornings but fine when weather not so cold so don't think a problem with injector seals or air leaks. Started first go this afternoon after standing for 14 hours

Glow plug fuse fine but cannot find glowplug relay. It is not in fuse box with other relays

Any idea where it might be?

I guess that I can test this on a cold morning with a voltmeter from the glow plug cap to earth?

Also car has never displayed a glow plug light on dash and handbook does not show one

Will test glow plugs tomorrow can I assume that if they glow they are fine?

Anything else I should look out for?

Regards

Tony

Reply to
TMC
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It wont be using its glowies above about 4 deg C, so unless its been down to that where you are, its not the glows. (unless Saab have altered ECU software from GM's usual)

Are you certain the battery / starter are upto scratch, as it is relying on a decent cranking speed when cold.

As a small experiement, try parking it nose down with a fuel tank more than

1/2 full if possible and see how it starts. If fine, then you definately have fuel draining back to the tank (injector seals or another leak)

Tim..

Reply to
Tim..

Yes but make sure you go from glowplug cap to engine housing (not battery -ve) otherwise you would miss a problem with a broken earth strap if there was one. Obviously this test will not detect one or more dead glowplugs (doesn't detect whether current is being drawn). However if the battery voltage is a good +12V plus, and the battery is believed to be in good condition, then if the voltage across the glowplugs is dropping to say

9-11Vish then it is a good sign that significant current is being drawn by something, hopefully the plugs.

If you're feeling very dodgy, then using a jumplead and screwdriver,

*carefully* short the +ve of the battery to one of the glowplug caps, just for ten seconds, then remove, and very quickly dash round and turn over the engine. If it suddenly starts beautifully when normally it would not have done, then it indicates that the glowplugs are not getting energised for some reason.

However, if one or more of your glowplugs has failed to a short circuit, you will die horribly in the battery explosion that ensues. :-) But carrying around a jumplead and screwdriver for the purpose of bypassing a failed glowplug fuse or relay is still one of my favourite wheezes.

Reply to
Vim Fuego

the common fault is the spill pipes, if they are not recent replace them as a first step

Reply to
mrcheerful

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