2.0 HDI 110 occasionally jerky under full acceleration

bencowell · Post by **bencowell** » 21 Jan 2006, 21:24

My 2002 C5 HDI 2.0 110 has been a little jerky under full acceleration for the last couple of days. It is intermittent and only seems to happen around 2,200 to 2,600 rpm. I only accelerate hard when the engine is warm through.

Changed the air filter last week and removed the fuel filter but replaced it because had wrong spare part.

I always run on Shell Extra and currently have 1.5 times stregnth Millers Diesel Power Plus to clean up after old dirty air filter choking the engine.

Has anyone any ideas?
Thanks. Ben

AndersDK · Post by **AndersDK** » 21 Jan 2006, 22:43

Ben -

A diesel can not be "choked"

- because of the working principle.

It can be overfuelled - but I dont think your C5 HDI ECU would allow that unless it is tangled with or at fault.
Standard problem for hesitating or jerking diesels are leaking fuel lines at the low pressure feed side - allowing for air to get in.

Rule of thumb : if you DIY on your car and suddenly gets new symptoms after such work - suspect your last work. It always pays (how do I know

)
In this case suspect the fuel filter assembly and fuel lines thereabouts.

bencowell · Post by **bencowell** » 22 Jan 2006, 07:38

It worked fine for a week. There are no visible leaks and everything feels secure.

I understand the HDI low pressure fuel system is pressurised rather than under suction like the XUD, so any pipe problems would show as a leak rather than air being sucked into the fuel.

I've obtained the correct fuel filter and will replace it today.

Could there be an EGR fault as the pace of acceleration seems to improve after the jerk?

wheeler · Post by **wheeler** » 22 Jan 2006, 12:43

bencowell wrote:
Could there be an EGR fault as the pace of acceleration seems to improve after the jerk?

shove a small ball bearing down the pipes of the EGR valve & the throttle butterfly or just clamp them off to rule out this problem.