Citroen Picasso Diesel Miss-fire - pork pie
Any Advice Please?
I have recently purchased the picasso 2.0 hdi which has covered about 3,000 miles.
I have never owned a diesel before and have noticed that after being on a run and while waiting at some lights or at a roundabout, the engine seems to judder intermitantly at tickover almost like a single miss-fire on a petrol engine, you can feel the wobble through the cabin on what is usually a very smooth performer with little vibration.
Could any of you diesel experts point me in the right direction as to what i should be asking the dealer to look for, what things could cause this imbalance on a new engine.
Cheers.
Citroen Picasso Diesel Miss-fire - Railroad
The fuel injection pump isn\'t timed like older diesels, they have common rail high pressure fuel systems.

The fuel injectors are switched electronically by an ECU (Electronic Control Unit) and voltage increases to about 80V when opening to overcome very high fuel pressure (about 30,000psi, 1800bar). Assuming that the car has had no previous overheating problem leading to head gasket failure and compression problems, I\'d say you either have an ECU fault, or more likely a hosing injector. You can get the injectors tested at a diesel fuel specialist such as Lucas, or maybe your Citroen dealer.
Citroen Picasso Diesel Miss-fire - pork pie
Thanks railroad,
what do you mean by an hosing injector is this something to do with the spray pattern ! apologies for my ignorance.
Citroen Picasso Diesel Miss-fire - Railroad
Yes exactly. Fuel should be injected in a fine spray to atomise properly, and not in a jet which wouldn\'t atomise so well.
Citroen Picasso Diesel Miss-fire - pork pie
could an additive help this problem if the injector is defective
Citroen Picasso Diesel Miss-fire - David Lacey
I wouldn't go 'telling' your dealer what to look for - it'll probably get their backs up - it would me!

If you have a fault - then it is ultimately fixable under the warranty, surely?
Citroen Picasso Diesel Miss-fire - Alf
Yep, at 3k miles the car has full warranty so its back to the dealer if I were you. (But don't be surprised if the response is, 'They all do that' or 'Never heard of that before')!

My HDi Picasso has covered 11k and has never missed a beat, and neither should yours.

Regards,

Alf
Citroen Picasso Diesel Miss-fire - pork pie
Car is booked into the dealers on monday , I will let you know what happened.
Citroen Picasso Diesel Miss-fire - Peter D
I thought these HDI's had a common rail feed at about 10 bar and the injector themselved pulsed the fuel in at about 1800 Bar. The need for the high pressure is to inject it into the cylinder before it combusts in the injector due to the high pressure. Do they reall run the common rail at 1800 Bar that must be some pump ! Regards Peter
Citroen Picasso Diesel Miss-fire - pork pie
i agree that is some pressure.not to be tampered with.
Citroen Picasso Diesel Miss-fire - RichardW
The common rail does indeed run at high pressure. Current common rail pressure is around 1650 bar. Target is 2100 bar IIRC. VW's unit injector system (PD) uses a low pressure feed and a cam at each injector hikes the pressure up - this is why they need such a special oil, as the shear on this cam is extreme.


RichardW

 

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