In France - Bongo not starting

[teenmal]

Glad you made it back to the UK & sorry to still hear of your problems.

I've been outside & measured a glow plug on mine. Results are as follows:-
Outside ambient air temp 15*C
Glow plug resistance when cold 1 ohm
Heat glow plug for 5 secs (tip glowing red) resistance 48 ohms.(This value falls back to 1 ohm very quickly as the glow plug cools)

This shows that each glow plug is drawing between 12 Amps when at ambient air temperature & 0.25 Amps when hot.

I suggest that you fit a proper new fusible link.

If you can't get a Mazda one, you should be able to obtain one from a vehicle garage (Ford, VW ) that deals with diesels.The crucial part is that the fusible link is fitted to a four cylinder diesel engine. I'm sure if you speak to a "parts person", they'll know what you are talking about.

Have you actually removed the glow plugs from the engine & inspected them.?
If you haven't it may be worth doing just to rule out any problem.
To test the glow plugs once they are removed from the engine, you connect the positive pole (using fairly thick wire) to +12 volt & the screw/thread to battery earth. The glow plug tip should glow red after about 5 seconds, if they do this you can stop the test as the glow plug is working OK.
WARNING. The glow plug body will get hot during this test.

My NGK plugs have this & the number stamped onto the socket flats. This may help you identify what brand of glow plugs you have fitted.

Nigel

[missfixit70]

Which is all very well, but I'd buy a few, cos I reckon there's still another issue. Be happy to be proved wrong though

[eoptio]

Hi

yes agree, get a few as problem not yet solved....

The relay seems to work ok, gives 12V for 10-15secs after turning the key, then 0V, then once started I keep getting 12V for a while until the engine has warmed up/gets to certain revs.

I think next step will be to get new glow plugs, then try again with the new plugs and see what happens. If that still does not work I think it's time for the garage to have a look at it as I seem to be going round in circles on this one...

Thanks all

K

[missfixit70]

Did you see this at the end of that last link I posted ?

Problem solved there was a short on the main wiring loom(tight turn into the engine bay). ripped loom apart re-made joint and insulated nice feeling when you've found it

[eoptio]

hi

yes thanks saw that, have not yet taken the whole loom apart (did the beginning and end), I was thinking if there is a short on the wire, there should be a voltage drop on the wire between the relay connection and the glowplug rail end. I have checked for a voltage drop and could not find one (volt meter reading <0.1 volt), also tested for a voltage drop using an external temp wire connected to the relay and got the same reading as with the actual wire. If there would be a short on the wire I guess it should also blow a fuse when put under power if disconnected from the plugs, tried this with a 20A fuse, it did not blow so a bit odd....

Have also taken the relay apart, not visisble damage in there, connectors all ok.

I'll try to get new plugs, connect the whole lot via the relay with a known good wire and a 30A fuse, start it from cold and see what happens then.

Very tempted to send it to the garage now...

K

[missfixit70]

Could be it's a smallish drain, that when ADDED to the combined glow plug draw is enough to blow?

[eoptio]

brief update: replaced the glow plugs with new NGK ones, cleaned up all connections (including battery earth), connected the glowplugs via the relay with a known good external wire and a 30A fuse. Started engine and the fuse did not blow.

Connected it all using the existing wire, started engine, fuse did not blow. The engine was not cold at this point however, so plugs might be draining less power which may explain the fuse not blowing, however the wiring/fuse holder did not heat up as they did yesterday using the old plugs.

I think therfore the problem is either the glowplugs or the wire. To rule out the wire being at fault I will let it cool down again then start it using the existing wire and a 30A fuise and see what happens then.

K

[eoptio]

Hi all

brief update on this: just back from a trip abroad and no further starting problems. The 30A fuse I put in as a replacement for the broken fusible link is now working ok and no longer blowing when starting from cold. It therefore seems that the initial problem was caused by faulty/worn glowplug(s).

Thanks all

K