Glow plug power

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Singr07

Active Member
Posts
119
Location
Birmingham
Hi Folks
I need your help please on my Defender 90 with 300tdi conversion done by previous owner. Engine starts up without any issue but exhaust emit lots of smoke on start up only.

I thought to check up the glow plugs power. When I switch on the ignition, glow plugs light doesn’t illuminate on the dash board. I have also checked with a multimeter there is no voltage on the glow plugs (Yellow/black) wire with ignition switch on.

But when I start the engine then glows plugs light illuminates for a fraction of a second. There is no Glow plug relay under the bonnet and I can’t find Glow plug relay anywhere. When it try to trace the wiring backwards, Glow plug wire (Yellow/black) wire has connected with a Brown/red wire and that Brown/Red wire is coming from the main harness which goes straight into the fuse box. But from the fuse box it is going up somewhere into the dash board and not visible.

I am just wondering if that is how it normally sets up on a conversation? How do I supposed to know if glow plugs are getting the power when it requires?
 
Have you got the spring resistance 'position ' on the ignition switch?
I put my relay, 200tdi conversion, behind the metal fusebox mounting.
Edit...later models didn't have the resistance position so glows were timer relay controlled.
 
Flossie said:
Have you got the spring resistance 'position ' on the ignition switch?
I put my relay, 200tdi conversion, behind the metal fusebox mounting.
Edit...later models didn't have the resistance position so glows were timer relay controlled.
Click to expand...
Hi I did switched on the ignition and Battery’s red light illuminate on the dashboard. Sorry I don’t know what does mean by spring resistance. But Glow plugs ligh doesn’t come on. Does that mean it didn’t had any glow plugs replay at first place?
 
Is your truck a pre tdi model that has had a 300 conversion?
If so the previous models had no relay.
Glow plugs are ignited in the spring position on the key. It go's, turn key on and dash lights come on. Turn a bit more and feel the pressure of the spring, in this position glow plugs and the indicator lamp in dash light. Turn a bit further starter engages.
Power to plugs is direct from the ignition switch. This type of switch has some large thick wires on it and is rated for the job.
 
Hi yes it’s pre Tdi model. It only has one position to switch on the ignition then on the further turn it starts the engine. Please advise what would the best way forward
 
Singr07 said:
Hi I think it was the 2.5td diesel engine
Click to expand...
Sounds like you have a petrol ignition switch, fits to the rear of the ignition barrel, buy a diesel one, not expensive and fit that.
That's the easiest cheapest way or you could fit a stand alone glow plug circuit, a switch, cable and relay.
 
Flossie said:
Sounds like you have a petrol ignition switch, fits to the rear of the ignition barrel, buy a diesel one, not expensive and fit that.
That's the easiest cheapest way or you could fit a stand alone glow plug circuit, a switch, cable and relay.
Click to expand...
To add...are you sure there is no spring type resistance just before the engine crank position?
 
Flossie said:
To add...are you sure there is no spring type resistance just before the engine crank position?
Click to expand...
Hi Flossie, I’m being so dumb as I didn’t realise that yes there is a spring on that ignition switch and finally I have leaned it now how to use it. It does allow me to twist the key to spring and glow plug light come on. Thanks for your help you are a star 😇
 
Flossie said:
Sounds like you have a petrol ignition switch, fits to the rear of the ignition barrel, buy a diesel one, not expensive and fit that.
That's the easiest cheapest way or you could fit a stand alone glow plug circuit, a switch, cable and relay.
Click to expand...
Hi Flossie
It is 100% a spring action ignition switch. Recently it was struggling to start in the morning. I checked all of the Glow plugs and all were dead and were replaced with new Britparts Glow plugs. I thought to check the Glow plug relay too but it does not have any Glow plug relay. When I checked the main glow power cable with multimeter it does produce 12v when ignition turns to the Glow plug positioned. But when I connect all of the Glow plugs with main 12v then multimeter show around 9v. Could you please shed some more light on this issue which part number is spring action ignition barrel and which ignition barrel has stand alone glow plug circuit and how to wire it along with relevant parts. And how would this stand alone ignition barrel will work? Would the ignition needs to be turn to Glow plug first then turn the key to start position?
 
Britpart glowplugs are generally rubbish. You will get a voltage drop when all glowplugs are operating but does it start OK now? I let them glow for around 10 to 15 secs when it's frosty but that's with bosch glows.
 
Does the thick brown cable from the ign switch go to a resister on the bulkhead? It's a curly spring looking thing in a bracket, cable from that goes onto the glows. That thing isn't needed for a 200tdi just for earlier diesels. That 'might' be bringing down the voltage as I believe the glows on earlier diesels run at a lower voltage?
 
Flossie said:
Britpart glowplugs are generally rubbish. You will get a voltage drop when all glowplugs are operating but does it start OK now? I let them glow for around 10 to 15 secs when it's frosty but that's with bosch glows.
Click to expand...
I really appreciate your reply and thanks for you time and guidance. Previously I always started Defender 90 by straight turning the key like a petrol car and it always started without any issues. As I wasn't ware of the pre heating procedure that ignition switch need to turn and hold onto the Glow plug light position for few seconds. I only realized this last year when it was struggling to start up when cold, as I only drive it occasionally . This morning I held the ignition switch to Glow Plug position for 3-4 seconds and it felt like it drawn the whole battery power to start up and took slightly longer. I have just took out 1 of the Britpart Glow plug out and tested with a battery, it started to glow after 5 seconds. So I was wrong, I believe glow plug's position on the Ignition need to be held for minimum 8-10 seconds. I am going to order the BERU glow plugs and I will test both makes at the same time to see how log they will take to glow and how long they will stay on.
 
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Flossie said:
Does the thick brown cable from the ign switch go to a resister on the bulkhead? It's a curly spring looking thing in a bracket, cable from that goes onto the glows. That thing isn't needed for a 200tdi just for earlier diesels. That 'might' be bringing down the voltage as I believe the glows on earlier diesels run at a lower voltage?
Click to expand...
That thick brown Glow plug wire on the bulk head, comes out with main wiring loom. I will take a picture behind the speedo/dash and will post it here today.
 
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Singr07 said:
That thick brown Glow plug wire on the bulk head, comes out with main wiring loom. I will take a picture behind the speedo/dash and will post it here today.
Click to expand...
The resister I mentioned is on the bulkhead engine side, nothing to see behind the clocks other than the thick cable direct from the ign switch which can go straight to the first glow plug, number 4 cylinder.
That cable, for the original engine, would have gone to that resister on one side then another cable from the other side of that resister to the glow plugs. I think that the earlier engine glow plugs operated on a lower voltage hence the resister in circuit. 200tdi glows run on the full 12v so the resister isn't needed.
I ran mine through a relay so as to take the heavy electrical load off the ign switch terminal as there was evidence of heat damage. That terminal now just switches the relay which is a very light electrical load.
Doing this involves running a new heavy cable from wherever the new relay is sited to the glowplugs and a new heavy cable from the relay to the battery positive terminal or off a cable going to the battery like at the starter motor nut . That's 2 of the 4 relay terminals covered, the other 2 are one to a good earth and the other is the old wire going to your glowplugs at the moment, suitably rerouted.
 
Flossie said:
The resister I mentioned is on the bulkhead engine side, nothing to see behind the clocks other than the thick cable direct from the ign switch which can go straight to the first glow plug, number 4 cylinder.
That cable, for the original engine, would have gone to that resister on one side then another cable from the other side of that resister to the glow plugs. I think that the earlier engine glow plugs operated on a lower voltage hence the resister in circuit. 200tdi glows run on the full 12v so the resister isn't needed.
I ran mine through a relay so as to take the heavy electrical load off the ign switch terminal as there was evidence of heat damage. That terminal now just switches the relay which is a very light electrical load.
Doing this involves running a new heavy cable from wherever the new relay is sited to the glowplugs and a new heavy cable from the relay to the battery positive terminal or off a cable going to the battery like at the starter motor nut . That's 2 of the 4 relay terminals covered, the other 2 are one to a good earth and the other is the old wire going to your glowplugs at the moment, suitably rerouted.
Click to expand...
Would it require a new ignition switch and/or barrel to install the glow plugs on a relay ? Any idea if the existing spring action ignition switch has any timer on it for Glow plugs?
 
Singr07 said:
Would it require a new ignition switch and/or barrel to install the glow plugs on a relay ? Any idea if the existing spring action ignition switch has any timer on it for Glow plugs?
Click to expand...
No, the spring movement of the ign switch would trigger the relay. You don't need or have a timer at the moment. Timers we're just a modern convenience like auto chokes, electric handbrakes and other unnecessary stuff.
 
That's a great news. Yesterday I tested the Britparts Glow glow out from the situ with another battery and they were starts to flow within 5-10 seconds in full.

This morning I turned the ignition switch to the position 1 then all of the dash lights comes up, then I turned the key position to Glow plugs light for 10 seconds then tried to cranked the engine and nothing happened. It felt like Battery had no power cranking power at al.

Thereafter I connected my RING battery charger with the jump starting settings. It started with half the key turn. I Don't know if this new Bosch battery from Amazon is faulty or but I had no issue to start the Defender afterwards several times. Anyway I bought new battery from Halfords and fitted in. I will try to start aging in the morning when engine will be cold to check if the battery was causing trouble or is it something else. May be starter motor or ignition switch.
 
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