XM TD COLD STARTING

Doc · Post by **Doc** » 31 Dec 2004, 21:27

A couple of days ago, I changed the glowplugs as the car has been hard to start on cold mornings. The old glowplugs were sooty but in good shape and were about two years old.
The new plugs are Citroen/Beru types and despite them being new, the engine still took at least 20 seconds of cranking to get going. I also tried the trick of cycling the glowplugs twice and this helped. What concerns me is the engine always started quickly until a month ago.
Once running it idles and accelerates well even when cold.
This afternoon I turned on the ignition (but not glowplugs) and then pumped the primer pump first. The car then started within 3 seconds of the glowplug warning light going out, all this on a stone cold engine and an outside temperature of 9 deg C.
As the plugs are new, I'm assuming the pre-heat control relay is playing up as when I connected a test lamp, the lamp went out as soon as the engine started. I was under the understanding that in cold conditions, the glow plugs stay on for post-start heating AFTER the engine starts, to help with cold running. Is this true?
What I would like to know is; If a diesel engine starts quickly after being primed does this indicate an air leak somewhere in the fuel supply?
If the engine takes loads of cranking to start- even with new plugs - can this indicate a preheat relay fault? I checked for continuity to the glowplug feed cables etc and all is well. When I tested feed to plugs with a test lamp, the feed cut out as soon as the glowplug warning light went out. The engine started within 3 seconds.
I seem to be getting two possible symptoms giving one starting problem.
Doc

NiSk · Post by **NiSk** » 31 Dec 2004, 21:35

Sounds like you've got both. The primary reason seems to be air leakage. Check (change) hoses from bulkhead to filter/water separator. If the hose goes via the pre-heater on the left hand end of the cylinder head (seen from drivers seat), disconnect hoses to it and connect directly to filter. Lastly check hose from filter to pump, and leak off hoses from injector returns to pump - they get really brittle and will break if you touch them.
This will probably solve your main problem.
//NiSk

oilyspanner · Post by **oilyspanner** » 31 Dec 2004, 21:39

Also check the cold start telay, older ones have a removable top, remove this and clean the contacts revealed, you might not be getting the full whack.
Stewart

Doc · Post by **Doc** » 31 Dec 2004, 21:44

Thanks gents!
I will have to go and investigate tomorrow as I'm working tonight. Hell of a way to spend New Years Eve!
Happy New Year to you all.
Doc