Freelander 1 Glow plug testing

Hi All,
With the recent cold weather, starting from cold has taken a bit longer than normal. About 4-5 scenes of cranking. It’s never not started and starts perfectly on subsequent starts. After reading various freds on trouble starting from cold I wondered if the glow plugs cold be an issue or part of an issue. Bearing mind I’ve recently replaced all the fluids and associated filters together with air, fuel, OCC, turbo solenoid filters they shouldn’t be the cause. Is it just ‘normal’ for such low temperatures (down to -7 some nights)?
To test the glow plugs, I thought about buying a Sealey TA125 current tester so I could do them individually in situ, before battling to get that out if dodgy.
What I’m a bit confused about is there is a YT video about FL1 glow plug testing that said the resistance of each was around 0.2 Ohms. By my calculations that’s 60A each (12v/0.2ohm), being connected in parallel would be 240A being drawn prior to ignition. The fuse is a 100A so something seems wrong.
Your views/ opinions on this would be appreciated.
Regards,
M.

Nearer 1 ohm I would have thought?

Haynes says a few ohms. My memory suggests between 1 or 2 ohms.

Key thing is, if they fail they are open circuit so obvious.
Also, resistance changes quickly when they they heat up so a low voltage dc ohmeter test is only a 'go no go test'.

Again, with current check, no current flow is a duff plug !! Reading doesn't much matter.

Thanks Stv,
That makes more sense. I’ll see if I can get a value of them.

Thanks again Andy.

MaxTheDog1 said:

Thanks Stv,
That makes more sense. I’ll see if I can get a value of them.

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A good plug will draw 10 to 12 Amps per plug. So a full set will generally give about 50 Amps of draw, if you have a way of measuring that amount of current.

Thanks Nodge,
I did consider making a shunt resistors to use with my meters. They’re good for 10A so I could give them a try. It’ll just show O/L if it’s higher than 10. But by the time you’ve bought wire thick enough and spent time calibrating it all, I think I’d rather buy one of the Auto current meters as mentioned above. It’ll come in useful in all sorts of ways for the FL and my Jag, and my brothers Merc ML. We usually each buy something useful - he bought a impact tool which I used on the FL recently.
This assumes they can be tested individually by disconnecting 3 at a time without any problems.
Cheers,
M.

MaxTheDog1 said:

Thanks Nodge,
I did consider making a shunt resistors to use with my meters. They’re good for 10A so I could give them a try. It’ll just show O/L if it’s higher than 10. But by the time you’ve bought wire thick enough and spent time calibrating it all, I think I’d rather buy one of the Auto current meters as mentioned above. It’ll come in useful in all sorts of ways for the FL and my Jag, and my brothers Merc ML. We usually each buy something useful - he bought a impact tool which I used on the FL recently.
This assumes they can be tested individually by disconnecting 3 at a time without any problems.
Cheers,
M.

Click to expand...

I did this for FL2 but might give you some ideas, good luck.

I have a Uni-T UT210e clamp meter which measures DC current ( as well as being a general electrical meter).
Think they sell for about £40 sometimes less.

Been using this on a 20amp range to trace leakage current on a couple of vehicles ( which worked brilliantly) but I believe it has a 100amp range as well.

Will give it a try on mine tomorrow ( although all my glow plugs may be duff).

Thanks Kevm and STV.

Of course, with immaculate timing the weather got much warmer so not sure if glow plugs are activating or not.

However with my little clamp on meter discovered that when I turn ignition on it draws about 13 amps ( 7 of which are for the fuel pump.....can hear it come on and then go off).

Suspect the 6 amps left mean that either the plugs are not coming on due to temp. or are all knackered ( which is quite likely ).

Also only drawing about 50mA when everything off ( probably alarm/ecu using this ).

What about putting the clamp on round one of the glow plug cables individually?
Regarding the weather, mine is back to starting as normal so I’m thinking it was just the cold. Going to check the plug’s resistance though.
Cheers,
M.

I would need to take some covers off to get to the glow plug leads....on my to do list

Just to update....changed out 3 faulty glowplugs ( snapped 4th one... )

Forgot to test each lead individually with my clip on meter, but tested battery output ( and it draws 60 amp -----14 of which is fuel pump etc ).

So it looks like each glowplug draws about 15 amps for about 5 seconds and then it drops back to normal.

Cheers Kevm.

You can check all glow plug continuity from the multi connector in the L shaped box. The connector is next to the glow plug relay and has 4 wires in a square formation at one end of the multi. They are individual wires to each plug and colours are: black with purple. Black with green, black with red and black with yellow.