Are glowplugs easy to blow?

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Rhothgar
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Are glowplugs easy to blow?

Post by Rhothgar »

Well. A productive hour getting 3 of the 4 glowplugs changed in the Xantia S1.

All is good in the world.

Took a while to start even though I thought I’d given the system a good prime.

Anyhoo!

Couple of things for the boffs out there.

The rechauffage switches back on after the engine fires and switches off either when:- the engine temp reaches 60 degrees or the throttle position goes past 1/3rd.

So is it the temperature sensor that sends a signal or the cold start throttle cable waxostat thing?

Bearing in mind that the 1.9TD S1 has no ECU and no throttle position sensior, how does it work

Finally, whilst checking the voltage post start I accidentally went from earth on battery to a glow plug and got an almighty spark!

I imagine they take a lot to burn out. Any thoughts or experience on this please?

Also, I tried to crack off the feed from the filter at the diesel pump by the throttle. Whole thing twisted and started to be the banjo pipe! No doubt I’ve weakened it. Should have held the big hex spacer with a 17mm spanner to stop it rotating… 🫤
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moizeau
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Re: Are glowplugs easy to blow?

Post by moizeau »

The waxstat just opens the throttle a tad raising the revs when cold. I knew the glow plugs came back on for a short time but didn't know it was controlled, thought it was on a timer in the relay on the XUD.

I wouldn't expect it to blow a glowplug. All you've really done is short the battery.
Pete
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Re: Are glowplugs easy to blow?

Post by Rhothgar »

moizeau wrote: 07 May 2023, 15:56 The waxstat just opens the throttle a tad raising the revs when cold. I knew the glow plugs came back on for a short time but didn't know it was controlled, thought it was on a timer in the relay on the XUD.

I wouldn't expect it to blow a glowplug. All you've really done is short the battery.
It’s got to be something simple.

Hopefully no damage done then.

Just need to get that last plug sorted when my mate lends me his special spanner.

There was no smoke or hesitancy on start-up which was a delight to experience once bled.

Hopefully, the Beru plugs will last much longer than the NGK’s that were in and no doubt MPG will be improved one short journeys with new glowplugs that actually work.
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moizeau
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Re: Are glowplugs easy to blow?

Post by moizeau »

Beru's are the way to go but I wouldn't expect a mpg improvement with how short they're on.
Pete
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Rhothgar
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Re: Are glowplugs easy to blow?

Post by Rhothgar »

moizeau wrote: 07 May 2023, 16:15 Beru's are the way to go but I wouldn't expect a mpg improvement with how short they're on.
No? Not with the improved atomisation.

The engine was so hesitant when it started before. Used to have to give it a good rev before setting off which, if the 1/3rd throttle thing is true, then it would surely be wasting fuel if fuel is left unburnt?
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CitroJim
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Re: Are glowplugs easy to blow?

Post by CitroJim »

Rhothgar wrote: 07 May 2023, 15:48 Couple of things for the boffs out there.

The rechauffage switches back on after the engine fires and switches off either when:- the engine temp reaches 60 degrees or the throttle position goes past 1/3rd.

So is it the temperature sensor that sends a signal or the cold start throttle cable waxostat thing?

Bearing in mind that the 1.9TD S1 has no ECU and no throttle position sensior, how does it work
Post-heating (rechuffage) on a mechanically pumped VP20 engine is controlled by the glowplug relay Roger. This also supplies the signal to the pump for cold advance - the electrovalve that can be seen on the lower front side (as you look at it) of the pump - not to be confused with the stop solenoid... Diesels need a bit of timing advance when cold as the ignition delay between the point of injection and the fuel starting to burn is somewhat longer when cold...

As said, the waxstat just ups the cold idle speed a little...
Jim

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Re: Are glowplugs easy to blow?

Post by Rhothgar »

Cheers Jim. Ah yes. The little disc. Must have a little look at that and see if the contacts are clean. IIRC, they look like a set of points.
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moizeau
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Re: Are glowplugs easy to blow?

Post by moizeau »

Don't be too concerned about it, my was disconnected by mistake on my 1.7TD BX and stayed like that for several months until I noticed it one day. Plugged it back in and couldn't tell a difference. I will assist if working but not the end of the world if it's not.
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CitroJim
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Re: Are glowplugs easy to blow?

Post by CitroJim »

moizeau wrote: 08 May 2023, 13:45 Don't be too concerned about it, my was disconnected by mistake on my 1.7TD BX and stayed like that for several months until I noticed it one day. Plugged it back in and couldn't tell a difference. I will assist if working but not the end of the world if it's not.
Indeed, unless the weather is really bitterly cold, the old XUD is happy with neither cold advance nor fast idle!

Good glowplugs are a definite must though ;)
Jim

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Re: Are glowplugs easy to blow?

Post by Rhothgar »

Despite changing the glowplugs, the car has developed a hard starting issue!

Wouldn’t start earlier so I pumped the primer bulb! Still no joy. Took an age.

Once started I noticed what appear to be a slight bubbling from the base of 2 injectors.

Despite that, they were there before and car was starting fine.

Will check fuel filter.

Presumably it’s probably an idea to remove tank filter and make sure there is no gunge on it.

I imagine this cannot be the issue as it wouldn’t even run right once started, surely?
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CitroJim
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Re: Are glowplugs easy to blow?

Post by CitroJim »

Roger, hard starting when all else seems OK can be caused by a lack of compression, either through valves not fully seating, rings or leaks past the injectors - that bubbling you speak of might be a clue...

First check is to make sure the glowplugs are receiving full voltage... They take a lot of current and a slightly corroded connection - likely on the base of the glowplug controller - can wreak havoc as it takes very little resistance to cause a fair old voltage drop. You should see at least 11V on them when the plugs are heating...

The XUD has a quirk whereby the valve clearances are tightest when the engine is stone-cold.. As it warms and 'grows' the clearances open up. The cold clearances can go negative over time and hold valves just off their seats and with the concomitant loss of compression this causes, starting can be very difficult with attendant clouds of white smoke... I know it's a pain to do but it's worth checking the clearances just to rule this possibility out.

Rings will give themselves away by oil being burned when the engine is hot and running... This will be evident by blue smoke issuing from the exhaust.

And check for smoke whilst trying to start... It can give us a useful set of clues ;)
Jim

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Re: Are glowplugs easy to blow?

Post by Rhothgar »

It’s all good. Point of this post originally was that I was worried I had blown a New GP as I shorted it out while testing voltage.

Cylinder head done two years ago.

11V checked when GP’s fitted.

Reshimmed the valves so not them.

Yes. Before GP’s, there was a lot of white smoke but that cleared with the new GP’s.

No oil smoke coming from dipstick. .

As soon as it lets me down, I’ll be scrapping it. One owner. I’ve had enough. Have too ouch on my plate to be worrying about the cars as well.

I won’t be wasting time checking valve clearance again. Went to a LOT of effort to get those right.
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moizeau
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Re: Are glowplugs easy to blow?

Post by moizeau »

May be worth checking the old glow plugs if you still have them, connected directly to a battery. If they glow like really hot red worm within 5 secs, then glow plugs weren't the initial issue.
Don't lick them whilst red........or for several minutes.......
Pete
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Hell Razor5543
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Re: Are glowplugs easy to blow?

Post by Hell Razor5543 »

Id the glowplugs glow at the tip they are OK, but if they glow further further up the element they may be on the way out. Make sure not to have anything flammable nearby.
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moizeau
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Re: Are glowplugs easy to blow?

Post by moizeau »

James, his plugs are new to resolve a starting issue. I just mentioned checking the removed plugs to eliminate them from the original/presumed issue
Pete
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