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Advancing Timing on 300tdi EDC


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I've been advised that my 300tdi EDC would start better if I advanced the timing slightly, this is from someone who had exactly the same as me.

How is the timing advanced on the 300tdi EDC? Is it through the ECU - so it needs an independent with testbook or equivalent or is it more basic like the series where you just turn the pump.

I must admit I am being lazy and haven't even looked under the bonnet to check if it can be turned but thought I'd check here first!

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Ah found it through the wonders of searching!...

I had very similar problems with an old 300Tdi Auto I had. Advancing the timing ever-so slightly was a tip given to me by Jeremy Fearn and was something that worked for me having already tried much of what you've already carried out. Apparently lazy starting is a very common fault on 300Tdi Auto Discos.

Remove the small circular plate that you see on the front of timing case secured with three 10mm bolts.

With the cover and paper gasket removed, slacken the three 10mm bolts you’ll now see on the circular plate inside the timing case.

Turn the large nut in the centre of the plate CLOCKWISE approx 5mm to advance the timing ever-so slightly.

Retighten the three bolts on the circular plate and go for a test drive before replacing the inspection cover.

After a short distance my ‘Check Engine’ warning light came on and the engine went into limp-home mode.

Jeremy Fearn had pre-warned me that if this happened, I’d been a little too generous with my 5mm. If this happens to you, loosen the three bolts and back off the large nut a fraction, tighten everything up and try it again.

Another trait mine displayed simialr to yours were the lazy battery symptoms. After fitting two batteries, the fault turned out to be an intermitent starter motor fault.

With lazy starting and a dodgy starter, the two problems compounded each other.

Hope this helps


Does that sound OK? Do I need a replacement paper gasket - or does it not matter for there? If I do - do I need to put a new one on each time I alter it until I get it perfect?

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I presume the timing cover is replaced with the aircon idler on aircon models?

I removed the aircon idler, slackened the three 10mm bolts and turned the 22mm nut clockwise about 5mm, replaced the aircon idler then went for a drive.

Start up was encouraging as it rev'd itself a bit on start up which it never normally does.

Taking it out for a drive, it was fine whilst booting it and was fine most of the time, but if I idled for a while (ie at lights) then set off, the CEL came on and it wouldn't let me rev past 2500rpm - dropping the revs back to about 1500rpm knocked off the cel and I could then rev again.

So I came back and turned the nut anti-clockwise about 2mm. The CEL no longer comes on but it also didn't seem to rev on startup like before.

So I guess I'll just have to wait and see

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Adjusting the timing by even a tiny amount makes a huge difference - I adjust it 1mm at a time. You would of course need to know that the timing was as it left the factory before you start to adjust it otherwise you don't know if it's already advanced (or retarded).


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If your truck wont start properly then playing with the pump timing is not the answer.EDC controlled 300Tdi's dont start like the mechanically governed ones,but if it wont go from cold then something is wrong - it should.They suffer all the same issues,poor earthing,tired starters,cheap aftermarket alternators etc.BUT they do need their glow plugs working properly - unlike the others.

If you are not aware, the EDC system is, of changes to the pump timing via the pump sprocket adjustment - from info from the crank sensor and point of injection,(From the needle lift sensor on No4 injector) the ECU knows exactly were the crank is and will protest if it does not see what it wants.The pump advance is set by the ECU via the stepper in the EDC pump itself.From your earlier driver demand issues I think it may well be time to get some help from a good Diagnostic/fuel shop.

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Thanks for the replies,

This is a last attempt before taking it to DLS, but so far so good.

The point I had got to is/was:

Glow plug issue fixed (cleaned up glow plug relay connectors)

TPS fault - Fixed cleaned ECU connector and earth point next to ECU

The only fault I was then left with was poor starting in the cold - or rather random starting. The starter motor turns over perfectly fine and there is plenty of voltage and the voltage drop isn't too great. If it's going to start it will start straight away. The starter spins well but no fuel is supplied. I have advanced the timing marginally and so far so good - so I'll wait and see!

Two people have mentioned that it's a common problem on the EDC Autos, and both have advised that advancing the timing as above fixes this issue, so it's worth a shot

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Fixed mine the same way a few years back and whilst it never burst into life like my older 300 and 200 it was much better.


Thanks for the further vote of confidence. Fingers crossed it's got it.

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