300tdi erratic Idle/stall issues...

Hi fellas, Recently refreshed a 300tdi that had been sat for a while. New fuel pipes, lift pump, filter, serviced injectors.
The problem I'm having is an bit of an erratic idle. It starts fine hot or cold but will almost stall afterwards (maybe 300-400rpm) before it brings its self upto speed with a quick tap on the throttle after about 10 seconds. it then idles a bit high at 900 rpm and it occationally falls back to the low idle (300-400rpm) if revved. once again this is fixed with a quick tap of the throttle.
Ive tried fiddling with everything people normally say and I am fairly happy I dont have an air leak etc.
Any ideas?
The only thing I can think that is perhaps the auto advance mechanism is stuck because if i retard the pump it helps a bit (but puffs out white smoke)?

(it drives and pulls great and no smoke when running normally)

exactly the same as this guys issue

I thought the engine in video sounded fine until he tried to make it run too slow , idle should be around 780-800 on 200
Try a clear tube from filter to injection pump that will confirm air or not
I had lumpy idling not revving properly last week and I’d managed to turn the fuel tank valves on my twin tank affair so it was sucking in air from empty tank , closed valves , primed and ok
It may be just simple have you checked the static timing

steve2286w said:

I thought the engine in video sounded fine until he tried to make it run too slow , idle should be around 780-800 on 200
Try a clear tube from filter to injection pump that will confirm air or not
I had lumpy idling not revving properly last week and I’d managed to turn the fuel tank valves on my twin tank affair so it was sucking in air from empty tank , closed valves , primed and ok
It may be just simple have you checked the static timing

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Thanks,
Yeah tried the clear pipe trick and no air on the feed or return. Has me scratching my head lol. Although the idles sounds ok I can't adjust it down any further and it's more the fact that when cold it sits in the low rpm range. If I give it some throttle I can get it to sit at normal idle speeds but until it's walm it don't want to idle properly on its own.

Have you checked that the return isn’t blocked at the pump end? Mine was on my 200tdi and had a poor idle,
Take the connector off and make sure the small bleed hole on the side is clear,

The engine idle speed is not normally adjusted with the cable , should be an adjuster under the wing side of pump for idle speed end of adjuster sits on the lever the cable pulls.

Europa486 said:

Have you checked that the return isn’t blocked at the pump end? Mine was on my 200tdi and had a poor idle,
Take the connector off and make sure the small bleed hole on the side is clear,

Click to expand...

Just taken that out and both inlet and out let's are clear (and the right way around).

Blackburn said:

The engine idle speed is not normally adjusted with the cable , should be an adjuster under the wing side of pump for idle speed end of adjuster sits on the lever the cable pulls.

Click to expand...

Yes I have adjusted it on the idle screw, but surely doing it on the cable is exactly the same. Both are just moving the throttle lever to a minimum point