300tdi edc misfire and throttle response

darland · Oct 17, 2019

Hello
Hoping you guys can help me with some advice please. Originally posted as an auto gearbox problem but things have moved on a bit.

Summary of issue...1. bad misfire when cold gradually improves as engine warms up. 2. Whether hot or cold there is a distinct delay in the revs picking up when I hit the accelerator (I've eliminated the throttle position sensor down by the accelerator pedal by trying a replacement). Issue 2 results in a couple of seconds delay pulling away (dangerous) and upto 5 seconds delay when on a ramp.
My mechanic has put a diagnostic tester on it but nothing showing up and no CEL lit.

darland · Oct 18, 2019

Come on people please I can't live without my Disco

lynall · Oct 18, 2019

Try the simple things first
Fuel filter.
Lack of fuel Ie lift pump on its way out? cheap and easy to swap.
Fuel tank sender steel pipes rotten letting air in?

If you google you can get all the voltage/ohms checks for the air flow meter

Iirc the throttle potentiometer is under the bonnet driver side on the inner wing.

There are specific measurements for the throttle and auto cable adjustments all done at the inj pump again Iirc.

darland · Oct 18, 2019

lynall said:
Try the simple things first
Fuel filter.
Lack of fuel Ie lift pump on its way out? cheap and easy to swap.
Fuel tank sender steel pipes rotten letting air in?

If you google you can get all the voltage/ohms checks for the air flow meter

Iirc the throttle potentiometer is under the bonnet driver side on the inner wing.

There are specific measurements for the throttle and auto cable adjustments all done at the inj pump again Iirc.

Thank you. As soon as we get a bit of dry weather here in Kent I'll do some digging.

lynall · Oct 19, 2019

darland said:
Thank you. As soon as we get a bit of dry weather here in Kent I'll do some digging.

If up top you are okay Canterbury/Dover way not so good.

Europa486 · Oct 19, 2019

Don’t forget you can use a direct fuel feed to the injection pump as it has its own lift pump
And this would eliminate all the rest of the fuel system,
If your power improves then you work backwards along the fuel system, if not
You are looking at getting the injectors and injection pump checked over,

darland · Nov 13, 2019

Thought I'd give an update on this as my experience may help others.

After having the injectors and pump checked out (tested ok) and worrying it could be ECU related or all sorts of other things (I always think the worst when there's an issue with the Disco!) it turns out I had got hold of a dodgy batch of diesel from my local supermarket (every little helps).

Drained fuel, new filter, cleaned sedimenter and filled up with nearly 90 litres of ESSO PREMIUM. Within 10 miles all symptoms disappeared. Will only be buying branded fuels from now on. It's not my daily driver so an extra few quid per tank is worth the peace of mind.

Thanks to you all for your suggestions on this problem.

lynall · Nov 13, 2019

darland said:
Thought I'd give an update on this as my experience may help others.

After having the injectors and pump checked out (tested ok) and worrying it could be ECU related or all sorts of other things (I always think the worst when there's an issue with the Disco!) it turns out I had got hold of a dodgy batch of diesel from my local supermarket (every little helps).

Drained fuel, new filter, cleaned sedimenter and filled up with nearly 90 litres of ESSO PREMIUM. Within 10 miles all symptoms disappeared. Will only be buying branded fuels from now on. It's not my daily driver so an extra few quid per tank is worth the peace of mind.

Thanks to you all for your suggestions on this problem.

Cheap/free fixes are always the best ones.

300tdi edc misfire and throttle response

darland

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darland

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lynall

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darland

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lynall

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Europa486

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darland

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lynall

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