General glow plug question - Citroen Relay

[Tetsu0san]

Morning all

I've got a 2003 Citroen Relay van with a 2.2Hdi engine in it. I've owned it for about 6 months and use it for band transport.

Anyway, it's always had an intermittent engine light come up on the dashboard so a couple of days ago I thought I'd investigate and the first thing I discovered that the glow plug relay was in a bad way indeed. The main live feed wire had at some point gotten very hot and the insulation had burned through and the terminal post in the relay housing itself had melted the plastic and was just hanging out of the bottom. It was a right mess. So I visited a scrap yard and pulled 3 of these relays out of 3 different cars and fitted the cleanest one last night.

So I think I'm right in saying that the relay is a timer and should liven up the plugs for a certain time (depending on ambient and engine temperature) and should then turn off? This one keeps the plugs live when the engine is running and the wire to the plugs gets very very hot indeed (it burnt my finger touching the terminal post). Is this right? Also, the voltage to the plug side terminal post is only at 10volts? Seems low, especially when it's just a relay inside and doesn't have any obvious voltage reduction circuitry.

I know the plugs themselves have a very low resistance and they draw a huge amount of current (20 amps each?) and usually when they blow they just create an open circuit. But can they blow and create a short? Could this be why the wire is getting so hot? But surely this wouldn't cause the relay to keep them live long after the engine is running?

I'm going to fit one of the other relays tonight in the hope that perhaps the one I've fitted is faulty, but I suspect I have another issue somewhere especially as the original one had gotten so hot in the first place.

Any help and advice will be greatly recieved

[wheeler]

It’s fairly normal for glow plugs to stay on for up to 5 minutes after the engine is running (known as post heating) depending on engine temp, its to get the engine warmed up faster to make it more efficient.
Its not unknown on DW8 engines for glow plugs to short. In these cases the relay normally cuts the power to all the plugs, must have some sort of internal short protection.

[Tetsu0san]

It’s fairly normal for glow plugs to stay on for up to 5 minutes after the engine is running (known as post heating) depending on engine temp, its to get the engine warmed up faster to make it more efficient.
Its not unknown on DW8 engines for glow plugs to short. In these cases the relay normally cuts the power to all the plugs, must have some sort of internal short protection.

Thanks for the reply. Is that the model of engine I have? The DW8?
Anyway, is a short is possible? I will have to look at them then to see what they're like. If you say the relay should cut the power, it certainly doesn't look like it is so perhaps they are actually OK?

The other thing is the heat from this wire. It's all tucked up underneath that plastic cover so you shouldn't ever actually get your hands near it, but I wasn't exagerating when I said the feed to the plugs burnt me when I touched it. Seems a little too hot to me?

I'm going to try one of the other relays to see what happens.

[Tetsu0san]

I fitted one of the other relays on the van last night and cleaned up the connector on the wire going to the glow plugs. This was an older revision of the relay, judging by the lack of a suffix A printed on the side. Didn't get a chance to test the plugs but I will another day.

The wire still gets hot, too hot to touch, but it does go on and off for the first couple of minutes that the van is running. Then after a while it will stop turning on the plugs, which is what I think it's meant to do.

Anyway, I'll monitor and see what happens.

[wheeler]

No, you have a DW12 engine but it could still operate the same as the DW8

[Tetsu0san]

No, you have a DW12 engine but it could still operate the same as the DW8

Isn't the DW12 fitted to the later model Relay? Mine is a 2003.

[white exec]

Are they the correct glow plugs?
Is the long feed wire leading to the GPs hot along its entire length, or just in local spots or near terminations/connectors.

XM originally designed with twin cables leading from GP relay to the four plugs. Later, some design idiot decided one cable would do instead, so the poor cable ended up carrying almost twice the current it should. Problems included very hot loop/eye connectors at each end, and reduced GP performance. Running a second cable alongside the first gets rid of all those isssues.

If your feed cable is getting hot, I would be concerned that it could damage other cables etc where it runs alongside. Might be worth abandoning that cable, and running a fresh one fom GP relay to the plugs. If replacing the cable, go for stranded 6mm2, or a pair of 4mm2, to cope with the 50-75A that four good GPs will pull.

If replacing GPs, go for BERU brand. Ring/eye connectors should soldered on, not crimped.

[Tetsu0san]

Is the long feed wire leading to the GPs hot along its entire length, or just in local spots or near terminations/connectors.

That is a very good point. The heat does seem to come from the eye/terminal first so perhaps, like the feed wire connector, the wire into the eye is the problem. The feed wire had pretty much melted the terminal out of the relay box and the connector actually fell off in my hand. It had obviously been getting very hot for quite a while before I started looking at it. It wasn't soldered, just crimped.

I will make up a new wire and fit that. See what happens.

[white exec]

Well spotted. That is exactly what I found on ours - a melted out eye connector at the relay end.

Crimped connectors carrying high current can have a limited life. The crimping force relaxes over time, and the contact deteriorates. With the high current, heat is generated, and the cable strands oxidise. Not uncommon to see them black rather than shiny copper. Weather can also get in (especially at the vulnerable front) turning copper surfaces green.

All this can happen to the main battery terminals too, where for years PSA used crimped-on lead (Pb) lumps. Eventually, starting can become difficult with both glowplugs and starter not getting enough current. Giveaway is usually the offending connector feeling warm or hot after cranking. Corrosion of the copper strands is hidden, so difficult to spot. Old lead clamps best replaced with decent brass ones, with bolt-down contacts, and the cable end cut back or cleaned up.

[Tetsu0san]

That seems to have fixed the glow plug issue. The wire is no longer getting hot and it all seems like it's working as it should. So thanks to all for the information.

And now I have other issues to fix..

[white exec]

Brilliant. Well done!

[wheeler]

No, you have a DW12 engine but it could still operate the same as the DW8

Isn't the DW12 fitted to the later model Relay? Mine is a 2003.

A 2003 will be a mk 2 Relay ?? It should be a DW12.
Around 2007 ish the mk 3 came out & they done away with the DW10's & DW12's in favour of the Ford PUMA engine.

[jgra1]

I think your engine is the same as mine in my boxer..

an odd engine but an ok one.. a '4HY' (I don't know if this is an alternative name for a DW12)

but it seems to be a 2.0 HDI with a little more stroke and no more torque! its an 8 valve used in the vans from 2002 to 2006..

I think quite a lot of 2.0 Hdi 8 Valve parts are shared with it, which makes spares a damn sight easier..

happy to be told i am wrong

saying that, it's been a long day and I am confused

2.0HDi fitted to xantia's / C5 S1

2.0 HDi 1998–2001 I4 8V DW10 TD (RHY) 1997 cc 66 kW (90 PS; 89 hp) @ 4000 rpm 205 N·m (151 lb·ft) @ 1900 rpm
2.0 HDi 1998–2001 I4 8V DW10 ATED (RHZ) 1997 cc 80 kW (109 PS; 107 hp) @ 4000 rpm 250 N·m (180 lb·ft) @ 1750 rpm


2.0 and 2.2 fitted to Ducato's / relays and boxers

2.0 JTD/HDi PSA RHV 1,997 cc SOHC 8v Common rail direct injection 84 PS (62 kW; 83 hp) @ 4,000 rpm 192 N·m (142 lb·ft) @ 1,900 rpm 2002–2006
2.2 HDi1 PSA 4HY 2,179 cc SOHC 8v Common rail direct injection 101 PS (74 kW; 100 hp) @ 4,000 rpm 240 N·m (180 lb·ft) @ 1,900 rpm 2002–2006

so, I think Wheeler is right.. it's a DW12 of some sort, the 4HY is a different code, but you can see the other 3 letter codes above,, RHY RHZ RHV .. either way, it's 100HP and 2.2 and the similar engine in the xant/c5 is 110HP and 2.0!

[wheeler]

DW10 & DW12 are basically the bare blocks. The other 3 digit codes are slight variations of the complete assembly.
RHY & RHZ are both DW10’s but one is the 90bhp & the other is 110bhp.
4HY & 4HX’s are both DW12’s