Jumping Glow Plugs?

twilly · Oct 22, 2023

So I put in a new ignition switch that wont heat my glow plugs (1986 Defender diesel NA)
I am waiting for the right switch.
In the mean time, so I can drive my truck on chilly mornings, for a few days....
Can I just connect the positive pole of my battery to the glow plug wiring harness for 15 seconds or so??
Just as a cheat for a couple of days?
I'm hopeful let me know!

And thank you for your advice, time, knowledge....
Tom

miktdish · Oct 22, 2023

Careful, they draw a lot of current ....

Turboman · Oct 22, 2023

twilly said:
So I put in a new ignition switch that wont heat my glow plugs (1986 Defender diesel NA)
I am waiting for the right switch.
In the mean time, so I can drive my truck on chilly mornings, for a few days....
Can I just connect the positive pole of my battery to the glow plug wiring harness for 15 seconds or so??
Just as a cheat for a couple of days?
I'm hopeful let me know!
And thank you for your advice, time, knowledge....
Tom

Welcome to LZ!

That would be a 1986 Ninety, or One Ten, as the case may be. Defenders started in about 1990.

As long as you have 12 volt glow plugs, I doubt you will harm the vehicle by doing that.
But I wouldn't recommend it on the grounds of safety, any sparks could make your battery explode.

twilly · Oct 22, 2023

Turboman said:
Welcome to LZ!

That would be a 1986 Ninety, or One Ten, as the case may be. Defenders started in about 1990.

As long as you have 12 volt glow plugs, I doubt you will harm the vehicle by doing that.
But I wouldn't recommend it on the grounds of safety, any sparks could make your battery explode.

Cheers happy to be here! Yes it's a 1986 90 2.5 diesel NA. Not a Defender : )
Hear you loud and clear-- It's just that I drive my truck every day and until the new switch set arrives looking at alternatives to toasting a battery for no good reason....
Really appreciate your time and advice,
Thomas

twilly · Oct 22, 2023

miktdish said:
Careful, they draw a lot of current ....

Yes!!! : ) Thanks, for real. Thomas

Turboman · Oct 22, 2023

twilly said:
Cheers happy to be here! Yes it's a 1986 90 2.5 diesel NA. Not a Defender : )
Hear you loud and clear-- It's just that I drive my truck every day and until the new switch set arrives looking at alternatives to toasting a battery for no good reason....
Really appreciate your time and advice,
Thomas

Unless you live in Sweden or Alaska, there is every chance it will start anyway at this time of year.
Spin it over for ten seconds, give it a rest, and try again, it will probably start after a couple of goes.
Even better is if you can park at the top of a slope, roll start in second works very well.
If your battery can't take a few ten second spins, you are going to need a new one when the cold weather kicks in anyway,

twilly · Oct 22, 2023

Turboman said:
Unless you live in Sweden or Alaska, there is every chance it will start anyway at this time of year.
Spin it over for ten seconds, give it a rest, and try again, it will probably start after a couple of goes.
Even better is if you can park at the top of a slope, roll start in second works very well.
If your battery can't take a few ten second spins, you are going to need a new one when the cold weather kicks in anyway,

Alaska for skiing, fishing, and Sweden for almost everything else

twilly · Oct 22, 2023

twilly said:
Alaska for skiing, fishing, and Sweden for almost everything else

I've been doing this dance with this truck for 10 years....
Leaving her in a parking lot, minus 14 degrees and coming out of the lodge
with friends and she won't start. Friends really enjoying this moment btw....
I've roll started in third never in second and either way it takes atmospheric reentry speeds and
I live in the flats; no hills....
Maybe it's just the compression in an old truck but I have tried every trick, I think.
Lift pump, new burly batteries...

lynall · Oct 22, 2023

twilly said:
I've been doing this dance with this truck for 10 years....
Leaving her in a parking lot, minus 14 degrees and coming out of the lodge
with friends and she won't start. Friends really enjoying this moment btw....
I've roll started in third never in second and either way it takes atmospheric reentry speeds and
I live in the flats; no hills....
Maybe it's just the compression in an old truck but I have tried every trick, I think.
Lift pump, new burly batteries...

You can get after market heaters that fit into the inlet manifold, which basically set fire to a stream of diesel so the engine will fire up?
Back in the day many diesels used these as standard fit.

lynall · Oct 22, 2023

Like this, https://www.asap-supplies.com/products/thermostart-plug-for-perkins-4108-diesel-engines-162050

Iirc all they need is a 12 volt power supply and a fuel supply.
You flick the electric switch, this heats up a metal strip which when hot enough then allows the diesel to enter, the diesel catches fire and away you go.

tottot · Oct 22, 2023

As a temporary measure make a solid connection at the batt and at the plugs with a suitable [ thick ] wire. In the middle fit a switch, something chunky like a batt isolation switch.

K14 · Oct 22, 2023

Turboman said:
Welcome to LZ!

That would be a 1986 Ninety, or One Ten, as the case may be. Defenders started in about 1990.

As long as you have 12 volt glow plugs, I doubt you will harm the vehicle by doing that.
But I wouldn't recommend it on the grounds of safety, any sparks could make your battery explode.

Good point about calling a 90 or 110 a defender if it’s pre 1990, makes a big difference to this post.

twilly · Oct 22, 2023

twilly said:
I've been doing this dance with this truck for 10 years....
Leaving her in a parking lot, minus 14 degrees and coming out of the lodge
with friends and she won't start. Friends really enjoying this moment btw....
I've roll started in third never in second and either way it takes atmospheric reentry speeds and
I live in the flats; no hills....
Maybe it's just the compression in an old truck but I have tried every trick, I think.
Lift pump, new burly batteries...

lynall said:
Like this, https://www.asap-supplies.com/products/thermostart-plug-for-perkins-4108-diesel-engines-162050

Iirc all they need is a 12 volt power supply and a fuel supply.
You flick the electric switch, this heats up a metal strip which when hot enough then allows the diesel to enter, the diesel catches fire and away you go.

Whoa. Never heard of this and really interesting, thank you!!
Ha!! Never know where the next genius solution comes from : )

My whole starting thing has been glowplugs and fuel--
Some old Rover mechanic (not old mechanic, mechanic of old Rovers) told me that I just wasn't heating the glowplugs long enough. With the old trucks you have to heat them an actual 60 seconds, which seemed long, and this after cycling the lift pump by hand 100 times. This protocol actually got me through the low 20s and teens fahrenheit up north. Although with a big burp of white smoke on starting which means unburnt fuel which means still not really firing properly.
Everyone says "My truck starts in Siberia after parking on Lake Baikal overnight so there's something wrong with your truck" but I've tended to lots of farm and construction rigs through the cold-- They all have their quirks.
My truck is such a runner I just wish this was 365 days a year

Really appreciate the tips!!
T

twilly · Oct 22, 2023

K14 said:
Good point about calling a 90 or 110 a defender if it’s pre 1990, makes a big difference to this post.

twilly · Oct 22, 2023

tottot said:
As a temporary measure make a solid connection at the batt and at the plugs with a suitable [ thick ] wire. In the middle fit a switch, something chunky like a batt isolation switch.

twilly · Oct 22, 2023

Yeah, thinking alike bodge-wise : )
I bought a pushbutton switch today rated to 50 amps and some good thick wire.
My question is am I going to cook something in my ignition?
I want to have a connection from my 12 volt battery positive to my wiring harness for the glow plugs.
The plugs are grounded in the engine block does anything burn if I connect a positive 12v charge directly to the harness?
My understanding is that the factory connection is pretty primitive-- just 12 volts from the key in the ignition switch.
So I'm doing the same thing, right? Or am I an idiot? (Girlfriend frequently votes the latter

)
Thanks again so much for the thought and time put in on a kinda dumb question
T

mystery · Oct 23, 2023

may help

Turboman · Oct 23, 2023

K14 said:
Good point about calling a 90 or 110 a defender if it’s pre 1990, makes a big difference to this post.

Yes. I thought so too.

tottot · Oct 23, 2023

The ignition switch of Ninety's and One tens is a hefty unit designed to take the heavy load of glow plugs through it. Basic it is but it works.
Later switch's are light weight and will not handle the load. Had you ordered a switch for a Ninety or One ten you should have got the right one as mentioned above.
Even though my Ninety is now 200tdi engine the glows still work by holding key in glow position and not auto relay as is standard with later models.
As long as you wire button direct from battery it will work and glows will have noting to do with ignition switch.

Turboman · Oct 23, 2023

tottot said:
As long as you wire button direct from battery it will work and glows will have noting to do with ignition switch.

That is a good suggestion. I just did that on the generator engine on my boat.
It had a timer system, which wasn't working.
So I picked up the live from the battery and to the plugs, and wired them into a heavy duty push button switch.
So now I just turn on the key, push the button in for 20 seconds, and spin the engine over on the key.

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