Glow plug problems

[Alpinewoodsman]

My 90 was rather slow to start- even with 30 seconds heating time, it still took 10 seconds or so of cranking to catch....

Given it runs fine when going, an obvious possibility is glowplugs so I decided to change them.
Working from the front, I changed the first three, and then had some stuff to do, so ran about in it for 20 minutes. The three new plugs made no difference to starting.
After lunch, I tackled the last one- the most difficult to access due to all the hoses etc next to the bulkhead.

Tried it, and the engine cranks, but doesn't catch.

Tried putting the old one back...no good. Double checked package said 'for defender 2.5TD'

I noticed there was no earth connection at the end of the wiring loom- is that an issue? Or have I knocked a hose when I did the last one?
Advice or ideas welcome!

 

[Hicap phill]

As for the earth it uses the engine block as the earth. These run in series(1 linked line)
Check power to the plugs

As it's cold is the diesel viscosity affected?

 

[Flossie]

Knocked the connection off the stop solenoid?

 

[kevstar]

If you have power to the plugs my bet would be on the lift pump, id pump the fuel up manually & see if it starts any better.
Bleed the filter when your there & see if you get any air out.

 

[Alpinewoodsman]

Will do in the morning- battery is inside charging as I ran it down trying stuff.
I doubt it is fuel temperature, as it started fine earlier, when it was colder, and the engine was still warmish when I was trying to start it...

 

[Alpinewoodsman]

Ok...
Battery charged overnight...
Connection to stop solenoid knocked off.

No current to glowplugs!
Now to trace the lack of current..which would be the underlying reason for cold start issues.

 

[Flossie]

Ok...
Battery charged overnight...
Connection to stop solenoid knocked off.

No current to glowplugs!
Now to trace the lack of current..which would be the underlying reason for cold start issues.

? Just to be clear! The electrical connection to the solenoid HAS to be connected and good for the engine to run.
My earlier post was suggesting that you may of knocked the connection off whilst doing the glow plugs.
I'm reading your post as you've knocked the wire off now in an attempt to get it running?
Power to the glowplugs comes directly from the ign switch, this load is quite heavy and the switch can suffer as can the wires going to and from it(thick brown wires from memory).
Remove the column shroud and see if the wires look heat damaged on the switch. The switch can be replaced cheaply but a fiddly job.

 

[Alpinewoodsman]

Yes, I had knocked off the solenoid connection yesterday. It is now back where it should be.

I traced the glow plug wire ( thick brown and red) back through the bulkhead, but couldn't see it when I took the column shroud off- I thought it should be in there somewhere... the shroud is still off, so I'll have another look. Hope I don't have to take off more of the dashboard as well...

 

[Hicap phill]

Do the early motors have the glow on the ignition?
So turn your key 1 click for power.

Then does the key go 1 more position before engaging starter?
If it does this is where you hold the key to do the glows.

Have you not got a timer relay fitted?
You can wire up a relay & switch easily

Hope this helps

 

[Flossie]

Yes, I had knocked off the solenoid connection yesterday. It is now back where it should be.

I traced the glow plug wire ( thick brown and red) back through the bulkhead, but couldn't see it when I took the column shroud off- I thought it should be in there somewhere... the shroud is still off, so I'll have another look. Hope I don't have to take off more of the dashboard as well...

Pull the clocks forward, disconnect Speedo cable then you can pull the clocks further forward.
It's a bugger to get at for sure.

 

[Flossie]

Do the early motors have the glow on the ignition?
So turn your key 1 click for power.

Then does the key go 1 more position before engaging starter?
If it does this is where you hold the key to do the glows.

Have you not got a timer relay fitted?
You can wire up a relay & switch easily

Hope this helps

Straight off the switch up to TD, no relay although I've fitted a standard relay to mine to take the load off the switch wiring and contacts.

 

[Alpinewoodsman]

Got to the back of it. Unscrewed the ignition assembly to check connections there- all look sound and no signs of overheating or short circuits.

Looks like the problem is in the ignition switch.

 

[Hicap phill]

Get the multi meter out & check.

 

[Alpinewoodsman]

Get the multi meter out & check.

Resistance in switch between supply and glow-plugs when in pre-heat position.... 200K ohms. In cranking position....0.3 ohms. Problem located!

 

[nobber]

Im not surprised, 30 seconds on glow plugs is asking for a fire never mind a melted switch! What did you fit? NGK are the only plugs you should fit to these engines, the fact that there isnt a relay should reinforce the need for decent plugs. 30 seconds is madness, NGK recommend 6 seconds on their plugs, if you need more something is wrong,
if you give them more they burn out, then you think they need even more and they burn out even more, then you think they need 30 seconds, then your car catches fire.

 

[nobber]

Put it this way, its an unfused circuit, you have four red hot irons all glowing away, how many amps do they draw? So, your unfused circuit has a fault, all those amps are being drawn through a faulty switch, resistance = heat, heat = melting wires, melting wires on an unfused circuit = fire. The problem is its not really worth putting a fuse in the circuit so the glow plug circuit needs to be in top shape, if they arnt working properly its all too easy to be tempted to give them longer, probably why timer relays were introduced.

 

[Blackburn]

Most modern glow plugs are self regulating current goes down as temp goes up usually double wound.

 

[nobber]

They still won't last long being energized for 30 seconds at a time