Strange Problem

[Sherbet66]

Hi, 

 

I recently purchased a C5 2008 petrol 2.0 automatic Executive, on returning from the garage this developed a fault. At first the engine cut out when driving at low speed, this was coupled with a stalling/loss of power at cold engine start. I also noticed a throttle delay, especially around 2nd gear.

 

My local dealer diagnosed an issue with the injectors (that cost £110), they wanted another £200 to further identify the fault. 

 

The garage I bought it from took it back under their warranty and replaced the fuel pump and the fuel filter. This appears to have solved the engine cutting out but the other 2 issues remain, there is still loss of power/juddering at cold start (last  5-10 seconds) and a throttle delay when driving, up to 2 seconds when i put my foot down.

 

The garage have now replaced one of the fuel injectors that  they said looked "different from the other 3", this made no difference, they clearly don't know what the issue is, can anyone help?

[Sherbet66]

I should note that I don't know if the issue of the throttle lag and juddering at cold start are related.

[paul.h]

You could check if the engine coolant temperature sensor is giving the right temperature but a code reader with live data will be needed. Also clean the throttle plate with carburettor cleaner or a cloth damp with turps/white spirit to remove any carbon build up so it will idle better.

 

If it is the 2004 to 2008 C5 Haynes do a workshop manual that is worth getting. It says how to adjust the accelerator cable in case there is some slack in it.

[Sherbet66]

Thanks for that, its the 2008 onwards model. 

[Sherbet66]

This problem keeps happening, it happened 3-4 times last week, and then nothing for the last 5 days (the weather has been warmer). When the engine has started and i select drive or reverse when I put my foot on the accelerator and press down the rev counter drops from 800/900 to 500 and the engine exhibits stall characteristics. 10 seconds later and it's fine.

[paul.h]

As well as checking the temp sensor, you could clean the throttle plate/body to remove any carbon build up which could affect the idling.

[Sherbet66]

As well as checking the temp sensor, you could clean the throttle plate/body to remove any carbon build up which could affect the idling.

 

I'll pass this onto the garage I bought it from, many thanks. 

[NorIshoR]

Also, try a software update for Engine ECU / BSI and Gearbox ECU. Also, after update you will probably see that all the injectors are fine with no need to change.

 

+1 for the coolant temp sensor as stated above by @Paul H. BTW you don`t have an throtle body like petrol engines. You have an air distributor. Usualy no carbon is build there but you can check it anyway. Also, check that your turbo deliver the desired pressure - requested by engine ECU at low RPM (until 2100 rpm) you may have some problems there too.

Edited April 24, 2017 by NorIshoR

[paul.h]

I have checked the parts diagrams and it shows a throttle body for the 2.0 petrol engine, possibly you were thinking the car has a diesel engine. They do not show a turbo either. The update is a good idea but will need the car to go to a Citroen dealer.

 

Another thing I thought that could be checked is the accelerator pedal which is electronic. If there is any wear on the electrics it could affect the smooth progression of acceleration as the pedal is pushed down. I had to replace one on our 2003 C3 when the revs were not steady between idle and about 1700 rpm and it made it difficult when setting off. The resistance across the pedal terminals could be checked or a code reader with live data could show if the revs increase steadily as the pedal is pressed as well as show the throttle output.

[MikeLane]

To me it sounds like a (very) weak mixture on startup. Is it possible that the fuel pipe or something allows fuel to flow back towards the tank , creating an airblock and the car needs a few seconds to pump fuel from the tank to the injectors?

[coastline taxis]

if the garage your using plugs a scanner in and goes to live data then record it as your driving then it will tell them by the readings what is causing the trouble