Xantia 1.9td occasional hard to start

[aerodynamica]

Hi all, I only use the Xantia a couple of times a week and after sitting for a few days im now finding it is not starting easily. It seems to be that the glow plugs are not heating though when I checked there were getting volts they checked out. Symptoms are that it'll not catch until after a lot of churning over and when it does there's grey smoke and a lot of diesel smell from the exhaust.

After it has been running restarting is normal.

The glow plug light does illuminate.

Could the big relay be sticking when it's left to stand for some time?

[aerodynamica]

Should say: 4x plugs replaced last year and I just checked there that it is getting volts and then times out as expected.

[Peter.N.]

Its possible that one of them could have failed but also if the car is left standing for very long the oil can drain from the pistons causing low compression.

Peter

[ekjdm14]

If you have a clamp meter it'd be a better gauge to check the current the plugs are drawing since that's more indicative if a plug has gone down.

If you have just a standard multimeter don't try and measure current with that or it'll die a death since 4 good plugs draw around 80 amps+, but you could disconnect the busbar from the plugs and check the individual resistance of each one and see if any are wildly different.

What make of plugs did you fit? If you went with Beru then it's not as likely to have a problem there. Have you tried pumping the primer bulb till it goes solid before starting? the 406 did the same trick on occasion but I think that was down to fuel draining back and a pump up made things better.

[aerodynamica]

Thanks, well I can't recall what make they were but possibly bosch not beru this time. I thought that one duff plug was unlikely to cause issues? This is like the time I was trying to start my old XM 2.1 td with one working plug
Peter I see what you mean Re the compressions, is that still likely on a low ish miles engine? Might be. The priming bulb goes hard quite quickly and all the leak offs were done about 8 months ago but could be leak back I suppose. It does kick out a fair old stench of diesel before it catches though

[ekjdm14]

Just a thought, have you checked the valve clearances. Just remembered a gem of info that Jim told me, the clearances are tightest when the engine is fully cold so if they're tight it'll make cold starting near impossible due to low compression.

[RichardW]

If it's chucking out grey smoke, then it's a pre-heating problem not an air problem. First check has to be the plugs - ie take them out and check they are getting properly hot. As has been said, it's best to fit only BERU plugs in 1.9TDs - they just seem to eat other plugs. If that doesn't work, then check the valve clearances, as EK says, but this only usually affects cars with 150k+

[aerodynamica]

Cheers chapchaps will have a butchers

[white exec]

Quick compression check: disconnect the connection to the fuel cut-off solenoid, or otherwise prevent the engine from firing. Crank over, and listen to the 'resistance' that each pot offers. If all roughly equal, compression is not down.

GPs and GP relay would be my first check. Bench-test the GPs, or test one at a time in situ - each one should take about 15A, iirc. Check out the GP relay: look for heat-damaged eye-connectors to its HD terminals (= swollen cable insulation), and clean up all the external connections, and the contacts inside. IIRC there are two pairs of internal HD contacts.

Four good BERUs can pull up to 75A, if all the wiring and connections are good.

As mentioned, one of these Sealey widgets is handy for measuring hefty d.c. currents. It just clips over the cable in question:


They do a 30-0-30 and a 75-0-75A one. I'd go for the latter. On Amazon.uk.

[aerodynamica]

That's good pointers Chris, (no pun intended )

I had a check on leaving work about 14:20 ish and the first few times switching on the ignition, there was no click from the relay an on about the 5th try it clicked, held for the time and then clicked off. I feel initially that it might be down to a bad connection to the little transister inside the relay.

It also seems I replaced the 4x glow plugs with NGK made items and it did start on the button this afternoon with a bit of a puff of grey smoke (one duff plug?) , after sitting since about 08:30am so 6 h rest after a 6 mile drive this morning.

I will have a look tomorrow at the pugs (what resistance should each read straight? about 8ohms?) and I might replace the main 12v thick wires and ring connectors with new like I have with the battery leads. Winter being somewhat harder on old diesels.. it has done very well this winter though with this one issue being about all there is (well maybe the minor HP pump/ air in LHM issue... )

[Peter.N.]

About 1 ohm for normal glow plugs, probably less but you need a very good connection to get an accurate reading so anything around one ohm should be OK.

Peter

[aerodynamica]

Thanks Peter, I'm going to have a look at it tomorrow and see what's what.

Still need to get in touch with Mandrake to hook up his proper Lexia adapter to the hydtactive and clear the fault(s)... I have the Lexia copy software but the adapter is incorrectly made as explored in a former thread.

[white exec]

Resistance of GPs, cold, quoted by Citroen as between 0.4 and 0.6 ohm.
Difficult to measure such a low figure with your average test meter.
Best check is to power up each one in turn, and check the current it takes.
Better is to remove them, and test with a car battery on the bench: tip should glow orange within a very few seconds.
(Do not prolong the test, or exceed 12v - it can damage the plug unless it is screwed into metal to sink its heat.)

For 1.9TD, Beru GP is pt.no. 0 100 226 186 (GN909) - same as XM.

Good idea to check the heavy cables and their eyelets/ring connectors. If renewing eyelets, best to solder them on.

(JFI, on our XM, I wasn't very impressed with seeing a very hefty cable arriving at the GP relay from Batt+, but a less stout one leaving the GP relay and heading off to the GPs. I left the latter in place, but ran a second 6mm2 black multistrand cable alongside it, to beef up the arrangement. Before putting in the extra cable, the BERUs were pulling about 55A. With the extra cable, they pulled a healthy 75A. Starting has never been better. Not sure whether Xantia got this single 'economy' cable; might be worth checking at the GP relay terminals.)

GP pre-heat and post-heat times are determined by coolant temperature.

[ekjdm14]

Nice tip on the extra cable, I may put that one into practise when I replace our Xantia engine but I'll use 2 standard cables if I can.

[aerodynamica]

Ok, it's possible I misled: I found today one of the diesel leak off pipes was split at the end so replaced that. I might have found that the starting difficulty was due to the diesel priming up to fill a possible air gap caused by the split pipe and by the time it feeds to compression, the glow plugs might have timed out.....

I'll still be replacing the cable to and from the relay though.