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Glow plug relay help
Posted: Tue Feb 02, 2010 11:20 pm
by boyzie
Bongo won't start today. Its never had any problems until today.
Read a few threads on here and I suspect a problem with the glow plug relay.
When i turn the ignition the glow plug light comes on as usual, however, no click. I have tested the glow plug rail with a multimeter and it is receiving a voltage for perhaps 10 sec and then there is faint click and the voltage stops.
I have read there is a fuse next to the drivers seat, NO.9, however, they are not numbered on my bongo, anyone got a diagram of the fuses.
Also there is a 30amp fuse to test coming out of the battery.
Would the glow plug rail be getting a voltage if the fuses were gone? Any point testing them?
Does the relay need replacing? What does it do?
Any help would be greatly appreciated.
Boyzie
Re: Glow plug relay help
Posted: Tue Feb 02, 2010 11:25 pm
by Nevets
If the rail is getting voltage(12v) then the relay is deemed ok.
Try working the glow plugs 3 times then try to crank it over...
If it does try to start then it may well be a glow plug or two getting weak and the cold weather makes it worse.
Re: Glow plug relay help
Posted: Tue Feb 02, 2010 11:26 pm
by hembramacho
There's a fuse box diagram in a factsheet in the members area, if that helps?
Andrew
Re: Glow plug relay help
Posted: Tue Feb 02, 2010 11:39 pm
by boyzie
Nevets wrote:If the rail is getting voltage(12v) then the relay is deemed ok.
Try working the glow plugs 3 times then try to crank it over...
If it does try to start then it may well be a glow plug or two getting weak and the cold weather makes it worse.
Afraid that's not working.
What does it mean when it doesn't click?
Re: Glow plug relay help
Posted: Tue Feb 02, 2010 11:52 pm
by Nevets
if you have got power down at the glow plug rail it usually means the glow plug relay is working.
To be 100% the current is there you will need a amp clamp to check further.
Not sure why you cant hear it "click" it should..
Does the engine crank over ok?
I would start checking your immobilser(if fitted) fuel supply,fuel cut off solenoid etc,do a search and you should find topics on "wont start" and you can elimnate known/common faults..
you could always give it a whiff of easy start and if it starts up it will usually be faulty plug/s
But I'm sure someone else will also be able to give you a few other pointers soon.
Re: Glow plug relay help
Posted: Wed Feb 03, 2010 2:13 am
by patnben
Nevets wrote:if you have got power down at the glow plug rail it usually means the glow plug relay is working.
To be 100% the current is there you will need an amp clamp to check further.
If you have a DC clamp meter then each glowplug should draw about
4 Amps when hot - after about 5 seconds - so if all 4 glow plugs are
working you should be drawing about 16 Amps. When cold, glow plugs
are very low resistance so if your battery is in poor condition they may
not heat up enough to start the engine in cold weather, they need to
be red hot. Normally, the glow plugs should still remain switched ON
long after the glow plug light goes out, they should still be active until
the engine temperature gets up to about 50C. Post 1998 models seem
to be a bit more intelligent and will switch off much earlier.
Re: Glow plug relay help
Posted: Thu Feb 04, 2010 11:54 am
by Nevets
boyzie wrote:
What does it mean when it doesn't click?
Went out and checked my click very very faint so I wouldn't assume it's a relay fault.
Cheers Steve.
Re: Glow plug relay help
Posted: Thu Feb 04, 2010 12:27 pm
by ebygum32
Check your starter motor solinoid if there is "NO CLICK" that is where i would start especially if you are gettig voltage to the rail
Re: Glow plug relay help
Posted: Thu Feb 04, 2010 3:04 pm
by boyzie
Had to call out the AA. They sprayed a load of easy start into the air intake and that worked. He believed because we park it on a slant there may have been an air blockage in the fuel?
Anyway gunna take it for a spin to charge the battery and buy some easy start.
thanks everyone for the help.
Re: Glow plug relay help
Posted: Thu Feb 04, 2010 3:45 pm
by patnben
Go EASY on the Easystart Boyzie, too much and you could cause some
serious damage to the cylinder head.
Re: Glow plug relay help
Posted: Thu Feb 04, 2010 4:08 pm
by boyzie
patnben wrote:Go EASY on the Easystart Boyzie, too much and you could cause some
serious damage to the cylinder head.
Cheers. everything seems back to normal now so hopefully wont need it.
Re: Glow plug relay help
Posted: Thu Feb 04, 2010 8:25 pm
by dave_aber
Easy start in a diesel sounds incredible - like someone inside the engine with a BIG hammer!!
When I tried it in an old Citroen BX I thought I'd snapped the crankshaft.
Bit worrying, but all was well in the end

Re: Glow plug relay help
Posted: Thu Feb 04, 2010 8:50 pm
by mikeonb4c
patnben wrote:Nevets wrote:if you have got power down at the glow plug rail it usually means the glow plug relay is working.
To be 100% the current is there you will need an amp clamp to check further.
If you have a DC clamp meter then each glowplug should draw about
4 Amps when hot - after about 5 seconds - so if all 4 glow plugs are
working you should be drawing about 16 Amps. When cold, glow plugs
are very low resistance so if your battery is in poor condition they may
not heat up enough to start the engine in cold weather, they need to
be red hot. Normally, the glow plugs should still remain switched ON
long after the glow plug light goes out, they should still be active until
the engine temperature gets up to about 50C. Post 1998 models seem
to be a bit more intelligent and will switch off much earlier.
Another one of PatnBens rare but excellent posts. I've posted on here before my suspicion that some rough starting problems could possibly be down to insufficient battery power rather than just plugs (the whole thing is a moveable feast so hard to be sure what is causing what and when but...), so that cranking the engine reduces the necessary heating current to the glowplugs at the moment when a good low is required for ignition (and perhaps subsequent partial quenching results in a start, but a lumpy one). Something similar used to happen too with the spark plug engine on my old MG and its old battery - you had to press 'start' to swing the engine then release it quickly to get that vital spark, and it would start.
For that reason I reckon fitting a 95AmphHr battery is to be preferred over fitting a lower rated (e.g. 75AmpHr) one.
I wait to be shot down. No I don't, I've grabbed my coat and am almost out the door
