Mac-1990

Mac-1990

Member
Hi all,
Been a little while since I posted on here as landy has been sweet and life had been busy! Hooe you're all well!

So winters setting in here in West Yorkshire and its the first winter for me and my truck. So I've noticed on the first start of the morning when chilly she takes a few turns of the key then she fires up. Super low revs and sounds sluggish. Put my foot to the floor and it clears up to normal sounding engine which a huge puff of white smoke. Then it's fine for the rest of the day. When we had the frost and snow here on Monday I went out and the truck would not start for love nor money. Had to use some quick start to get her going. Went and got a new battery as thought it could be that.

So next morning the frost and snow is gone and she fires up like when a chilly morning.

So my thought now turns to the glow plugs. I've used a volt meter on them. When in 2nd place of the ignition I get a beeping on the meter but 0 voltage. I've tried on each plug and even the double red wire right at the beginning of the plugs. I've had the last and easiest plug out and tested it and it was glowing so bright all over. I haven't done the other 3 as there a little tricky to get to as the night drew in.

So I'm confused if I'm getting a beep to indicate a complete circuit but I'm not getting a voltage reading what could the issue be? Or am I overlooking something here? I wondered if it could be a nackered relay but I could only see one of those old type rubber push plugs before it disappear into the bulk head. Or is it if one or more plugs are buggered then they don't all get power??

I'm not a complete idiot when it comes to a motor but I'm not a highly experienced mechanic either. The truck is a ex mod 1985 110 so had the NA engine in it originally but has been converted to 200tdi (disco).

Any help or ideas or means to test stuff out would be greatly appreciated. I have no idea how old the plugs are but the last plug was black with soot when I pulled it but burned super bright all over when tested.

Thanks in advance.
20211203_152101.jpg
 
The 200 will start without glowplugs, but does start easier with them working.
Can you hear the glow plug relay clicking on/off?
Check for battery voltage on one of the fat wires at the relay, and then when you activatre the glow plugs via the key/button, see if the other fat wire also goes to battery voltage.
 
lynall said:
The 200 will start without glowplugs, but does start easier with them working.
Can you hear the glow plug relay clicking on/off?
Check for battery voltage on one of the fat wires at the relay, and then when you activatre the glow plugs via the key/button, see if the other fat wire also goes to battery voltage.
Click to expand...
Hi lynall thanks for the quick response. So I've heard about 200s not needing glow plugs but glad you seem to think they do better with them working so where might I find the relay? I unscrewed the fuse box metal cover and see a few relays. ones a new one for lights as it's clear and has wipac written on it. There's 3 I think with old golden metal coloured relays in and 2 that have no relay and have a wire bypassing the lack of relay. Will it be here or should it be somewhere else. I mean there might be a click but honestly I'm not sure.
 
On the standard 200 installation the relay is on the bulkhead by the back of the engine drivers side, from memory fat (brown?) wire from starter (but not the fattest actual starter one) runs to the glow plug relay, then same size wire down to the rearmost glowplug.
Do you have a seperate switch for the glow plugs or are they on the ign switch?
You are going to have to trace the wires, or if you stick up a pic of the drivers side of the engine/bulkhead someone might be able to see whats going on.

Wipac is just the makers name same as Hella etc, so dont assume that relay is for lights.

Maybe tomorrow using your jump leads, try powering the plugs direct, then see how it starts?
 
lynall said:
On the standard 200 installation the relay is on the bulkhead by the back of the engine drivers side, from memory fat (brown?) wire from starter (but not the fattest actual starter one) runs to the glow plug relay, then same size wire down to the rearmost glowplug.
Do you have a seperate switch for the glow plugs or are they on the ign switch?
You are going to have to trace the wires, or if you stick up a pic of the drivers side of the engine/bulkhead someone might be able to see whats going on.

Wipac is just the makers name same as Hella etc, so dont assume that relay is for lights.

Maybe tomorrow using your jump leads, try powering the plugs direct, then see how it starts?
Click to expand...

Ok good idea about the jump lead would I simply use the red to the positive and connect it to any of the plugs or at the first one? Also I assume the trucks normal ground wiring should be okay without the need of thr jump lead?
I've not noticed a switch for the plugs but then I have got one for a light at least I think it is but it doesn't do anything when switched I think it's meant to be for some rear spot lights that don't work. But I couldn't say for sure. The 2 relays that have a wire bypass. Could this be an issue or is it something to do with the conversion?
Only reason I suspect the wipac relay is for the lights is that I have paperwork for a halogen conversion and it clicks when hazards are on.
It was the only one I could work out lol.
 
Mac-1990 said:
Ok good idea about the jump lead would I simply use the red to the positive and connect it to any of the plugs or at the first one? Also I assume the trucks normal ground wiring should be okay without the need of thr jump lead?
I've not noticed a switch for the plugs but then I have got one for a light at least I think it is but it doesn't do anything when switched I think it's meant to be for some rear spot lights that don't work. But I couldn't say for sure. The 2 relays that have a wire bypass. Could this be an issue or is it something to do with the conversion?
Only reason I suspect the wipac relay is for the lights is that I have paperwork for a halogen conversion and it clicks when hazards are on.
It was the only one I could work out lol.
Click to expand...

Yes positive lead from battery to any of the glow plug little nuts, any plug will do 10 seconds max then disconnect the jump lead and crank it over, they earth through the body of the glow plugs themselves.
Iis exactly the same as how you tested that one earlier on, just with them fitted.

Conversions can be a real pita to work out whats what wiring wise, wiring always appears to be scary, but once you have a little understanding it starts to make sense.
 
lynall said:
Yes positive lead from battery to any of the glow plug little nuts, any plug will do 10 seconds max then disconnect the jump lead and crank it over, they earth through the body of the glow plugs themselves.
Iis exactly the same as how you tested that one earlier on, just with them fitted.

Conversions can be a real pita to work out whats what wiring wise, wiring always appears to be scary, but once you have a little understanding it starts to make sense.
Click to expand...
 
That year wouldn't have a glow plug timer relay, you would have to hold the key against spring pressure between dash lights on and crank.
Someone could have fitted the timer relay from the disco though of course.
Get yourself set up with the mm and get someone to turn the key to the dash lights on position and check voltage then, remember, if it does have the disco setup, the plugs will only have voltage for maybe a few seconds before the relay switches off depending on how cold ambient is.
If you get no voltage at all, try getting someone to hold the key in the position between dash lights and crank and check for voltage then.
Do you have that spring resistance just before crank?
 
Ahhh that makes sense warm it up disconect turn key with no wait. Yeah I managed to wire in an alarm for the old girl. Spurred off the fat white wire behind the key barrel and stuff. I've got a general knowledge and happy to try fixing stuff myself. It's just like spaghetti junction and with no easy way to see where wires are coming in. Last thing I want to do is pull the whole dash out. Done top end before but think the bottom can be more tricky.

In regards to getting a beep to indicate a complete circuit but no voltage does that make any sense to you?
 
Flossie said:
That year wouldn't have a glow plug timer relay, you would have to hold the key against spring pressure between dash lights on and crank.
Someone could have fitted the timer relay from the disco though of course.
Get yourself set up with the mm and get someone to turn the key to the dash lights on position and check voltage then, remember, if it does have the disco setup, the plugs will only have voltage for maybe a few seconds before the relay switches off depending on how cold ambient is.
If you get no voltage at all, try getting someone to hold the key in the position between dash lights and crank and check for voltage then.
Do you have that spring resistance just before crank?
Click to expand...
This is interesting! So I had another ex military truck before this one not for long but that's another story. I noticed the truck I have now the ignition barrel felt different almost like there isn't really a clear cut second spot before firing up. So I've been on my own and had the dash lights on(only a few even work) and tried testing for the voltage. So what you're saying is that between the dash lights coming on and firing up is the glow plug warmer switch so you'd hold it there before turning it the last way?
 
Mac-1990 said:
This is interesting! So I had another ex military truck before this one not for long but that's another story. I noticed the truck I have now the ignition barrel felt different almost like there isn't really a clear cut second spot before firing up. So I've been on my own and had the dash lights on(only a few even work) and tried testing for the voltage. So what you're saying is that between the dash lights coming on and firing up is the glow plug warmer switch so you'd hold it there before turning it the last way?
Click to expand...
Yes, that was the original way for that year, same as mine which was a 2.5na and now a disco 200. Still work mine off the key.
 
Flossie said:
Yes, that was the original way for that year, same as mine which was a 2.5na and now a disco 200. Still work mine off the key.
Click to expand...
This is such good info! I literally thought the barrel was a bit iffy and I just got used to it. But it is particularly spingy between the dash lights coming on and firing up I'll give this a try tomorrow to see if there's any difference! Also then I'll ask you as yours seems a similar setup. Should there be any relays bypassed with a single wire on a disco conversion or is it just bad play. I've noticed almost every fuse in the fuse box is a 10amp fuse obviously thay can't be right either?
 
It depends what previous owners have done.my glow plug wiring at the back of the ign switch showed signs of overheating so I used those wires to trigger a hd relay instead which takes the load off the ign switch giving it an easier life.
 
To add, the wiring for the engine is the same between the two engines in essence. They both have starter motor, oil pressure, water temp, stop solenoid and alternator cables, just lengths and colours vary and terminal ends. The alternator cable to battery is thicker on the disco because the output is higher but that's about it.
The wire from number 4 glowplug goes straight to the ign switch pre 200tdi 90/110 and the 200 conversion, like yours, can do the same.
The timer relay was just a way of removing pilot error like auto chokes - not needed.
 
Flossie said:
To add, the wiring for the engine is the same between the two engines in essence. They both have starter motor, oil pressure, water temp, stop solenoid and alternator cables, just lengths and colours vary and terminal ends. The alternator cable to battery is thicker on the disco because the output is higher but that's about it.
The wire from number 4 glowplug goes straight to the ign switch pre 200tdi 90/110 and the 200 conversion, like yours, can do the same.
The timer relay was just a way of removing pilot error like auto chokes - not needed.
Click to expand...
Thanks for sharing your knowledge I'm looking forward to seeing how cold it is tomorrow morning and seeing if this hidden glow switch works or not I shall update tomorrow's findings
 
You know, it woudn't surprise me at all if the installers of the engine didn't bother with glow wireing at all, given that a 200 would normally start well without.

Adding a decent relay and switch is a doddle if you just use a little logic, I have had to do that on Buttercup, if I can do it anyone can.
 
frog hopper said:
You know, it woudn't surprise me at all if the installers of the engine didn't bother with glow wireing at all, given that a 200 would normally start well without.

Adding a decent relay and switch is a doddle if you just use a little logic, I have had to do that on Buttercup, if I can do it anyone can.
Click to expand...

Yeah I thought this myself bloody mild here today so she'll probably start really well! Still gonna try. Seeing if it will fire up better whilst trying the sping key thingy.
 
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