Hi,
My xud isn't as good as I think it should be, so I'd like some advice (please) before taking it to the garage.
1. The length of time the glow plugs stay on for when starting from cold is very variable. Sometimes they go off after 1-2 seconds and lots of white smoke is produced when starting. In this case the idling speed is around 1000 whereas on a good start it is over 1100.
I've heard of something called a "waxstat", but there's no reference to it in Haynes. Otherwise glow plug control box thing.
2. Its a bit noisy and I struggle to get 45mpg. (Its done nearly 100,000.) Injectors/compression/valve clearances maybe? I know that injectors are expensive, but how much should I expect to pay to get the other stuff checked and sorted out if wrong?
Thanks.
Richard.
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Glowplugs quite straightforward, valve clearances easy to check, difficult to adjust. Lots of threads on the site
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I would do two things. Firstly get the glow plugs changed, at 100k if they're the originals then they are past their best. Secondly add one of those injector cleaners in the tank and take it for a good 'Italian Tune-up'. The XUD responds well to that.
I don't think the valve clearances are adjustable are they? Aren't they all hydraulic these days?
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The glow plug light should stay on for at least 5 seconds on an XUD - if it doesn't, this points to a problem with the glow plug controller. Note that the plugs don't switch off when the light goes out - they stay on for up to about 1 minute if no attempt is made to start the engine (as long as the controller is working!). Try waiting ten seconds after you switch on every time, and then starting. If it now starts nicely each time, the conroller is knackered. If it doesn't then either the plugs or controller, or both, are shot. You can easily measure when the plugs are gettting power with a volt meter.
The wax stat is fitted in the thermostat housing and runs to the injection pump. It should be tight when the engine is cold, then go slack as it warms up. Idle should drop from 1100 cold to about 850 hot. Cars built after about 1997, have a solenoid controlled vacuum system instead. On these the change from hot to cold idle is marked, and happens quickly, also if it's got air con, the fast idle should be pulled in when you switch the air con on.
You can reset the valve clearances, and this has been known to improve starting problems on higher mileage XUDs, but you have to remove the cam shaft and fit new shims. Not a 5 mnute job!
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RichardW
Is it illogical? It must be Citroen....
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Oh, and...
45mpg is about right for this engine - it's not a modern DI unit!If this is a late car, it might be fitted with the lift sensor on one of the injectors. If this wire has fallen off, or the sensor is bust, the engine goes into full advance, which can make it pretty clattery.
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RichardW
Is it illogical? It must be Citroen....
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RichardW, could you possibly explain what a lift sensor is, and do all XUD's have them?
Reggie
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Look at No1 fuel injector, if you have one there will be a wire coming off the injector.
It is there for engine timing purposes, in conjunction with the crankshaft sensor.
XUD Valve clearances? Easy on 306/205 etc etc but the associated turbo pipework on the 406 DHX engine is a right pain in the backside. Easily adds an hour to the job.
Then the stupid RH engine mouting and those three 16mm bolts.......grrrrr
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groups.msn.com/honestjohn - Pictures say a thousand words.....
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Here I go again about my departed 405 (atmo. XUD)
It went to 251K with no adjustments to valve clearances, injectors, and with just a couple of glow plug changes. Mid/late -'forties MPG was common. This engine is good for 500K if the cooling system does not let it down.
However, it did not run on supermarket fuel, but Total stuff.
Is the fuel filter fairly new, BTW? I was always amazed how much water was in mine every time I changed it.
I'm not sure if supermarket fuel would have an effect; it's been debated long and hard on these boards.
rg
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The valve clearance (it's always the inlets that tighten up) seems to only affect the turbo versions. Never seen a non turbo XUD with tight inlets, but have seen many TUD (both 1.4 and 1.5 sizes) with the very same 'fault'
The less-stressed non turbo engine seems more durable, I guess because of the lower stresses on it.
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groups.msn.com/honestjohn - Pictures say a thousand words.....
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