berlingo glowplug operation

[Dgen43]

Can anyone shed light on this please? On my berlingo 2008 b2 m59 i have had lumpy running on start-up, fine once up to temperature. 2 glowplugs faulty, all replaced but then told diagnostics indicated relay faulty so testing with Diagbox 7.57 i got this result:- activation tests for glowplug relay preheat and post heat relay heard to operate consistently but voltage test at plugs showed voltage at preheat but not at postheat consistently. Testing was done with engine cold and not switched on for at least 10 minutes. I guess there are two different conditions(temperature sensing) for the ecu control of the pre and post heat. Help please.

[Huskyxantia]

Most will say glow plugs only heat when very cold, so your running lumpy till warm might be something else . If your plugs heat at first start up and do what they should , relay should be ok, once engine is warm then plugs may only work as i did read ages ago 15 mins after running of the engine & then the engines own combusting process should work on its own without then need for glow plugs, as for the lumpy running when cold , is the air flow sensor ok ? Maf sensors do break there small element , there thin wire breaks , this can cause issues at start up. Have a look inside the maf sensor the thing that points down or up what ever way you look at it that has 2 wires in a square shaped thing , these wires burn the unit may look ok but burnt out wires means maf not working as it should.