intemittent judder 110hdi dsport

[lfcrule1972]

Biggie suggested a filter issue in another thread I think....

[gblue]

I have the same model only got a judder if I changed up to early, but this was when I first got it and I was getting used to a oil burner having mainly driven petrol motors for the past 20+ years. Have had it since November last year and had no issues with judder rattles etc, well I did shut down a car-wash because the auto-wipers came on, that'll teach me.

[spiffoiow]

Had the diesel DS3 in the garage today. They detected two of the four cylinders had fuel injectors which were out of tolerance. They apparently updated the ECU and did an extended road test to 'relearn' the injectors. It all sounds very clever. They even promised that the latest update would improve refinement and reduce noise - can't say that i really notice that (maybe its me being a skeptic) but the slight hesitation after coming back on throttle after the overrun has gone - so good news!
Hope you guys find this useful.

[lfcrule1972]

Nice one thanks for letting us know

[Chris_Blue]

So it was something to do with fuel flow
wonder how they became "out of tolerance" ? Hmmm.

[Jamie@SPTuning]

Injectors these days have to be coded to your ecu to work accurately. When an injector is made or reconditioned its put onto a test bed and checked for flow and break pressures etc... The test equipments computers then produces a hexadecimal code which is etched on to side of the injector body. This code is then programmed into the cars ecu corresponding to the cylinder it's fitted in.
This code is basically fine tuning, benefitting from better cylinder balance and smoother operation.



www.SPTuning.co.uk
Facebook.com/SPTuning.Ltd

[Chris_Blue]

So how would the injectors get out of tolerance in first place- or would they always have been out?

[cyclone]

So how would the injectors get out of tolerance in first place- or would they always have been out?

Chris as Jamie said each injector has a, call it a calibration code on it. This code is directly related to its individual fuel flow. Since it is impossible to manufacture each injector with the precise same flow rate. The manufacturer tests and rates them against an ideal injector. This miniscule difference in flow is the calibration code. When you program it into the ECU you are letting the ECU know exactly how much fuel each of the injectors flows so it can make adjustments to actually inject the same amount of fuel to each cylinder.

The programed code will not change but if a injector starts to become clogged the engine will be letting an uneven amount of fuel into the cylinders. Maybe the engine is learning relearning to adjust fueling based on feedback from the lambda sensor. But this would not really fix the problem just mask it for a while till the injectors become so clogged the engine will not run right at all.

[k20aje]

i took mine to the dealer last week around this judder and apparently the car needs de-coking on the exhaust vales side as they get coked up to easy to then i replied how they said driving the car to hard :mad: so i have booked it back in for the day as it takes a day to sort out

[spiffoiow]

Sounds possible that it has just the problem as masked as cyclone suggested. My car is now doing its judder intermittently again and the garage wouldn't even cover it under warranty.
So what would rectify the problem? de-coking - is that even a thing these days?!? or replacing the injectors - which presumably would be very expensive.

[Chris_Blue]

Why wouldnt they cover it under warranty?

[spiffoiow]

Because the car had a service (minor service) at a non-citroen dealer previously. Apparently they can tell when they plug it in?!? Secondly, after the first year, altering the cylinder timing is classed as an adjustment, not a fault. Sounds like pretty poor wriggling by my dealer and citroen UK again.