C5 2005 2.0L 136Hp Diesel Hesitation, Help Please!

[mseh1971]

I have a C5 2L 136hp diesel 2005 model that hesitates at 1500-2000 rpm. Not all the time, mainly in 2nd gear. Its had new injectors, new filters except for the exhaust. Any help would be most appreciated. 

[qman3428]

There are so many possibilities I would recomend putting it on a diagnostic, get the code and work from there, otherwise you can be throwing money away.

If you are mechanically minded cleaning the mass air sensor and the temperature sensor in the air intake is free and if it fixes it worth the effort.

[mseh1971]

1st thing i tryed. where is the EGR valve? looks like a water cooling device at the back of engine.On the passenger of the cooling device there is a black plastic cylinder with electrical plug on top of it, is that it? As it seems when I un-plug it the car drives perfectly with out hesitation.

[qman3428]

The egr just shows behind the cylinder head on the passenger side of the engine. It has a black coil on the top with an electrical plug going to it (mine is a yellow plug) and a metal pipe from it  to the inlet manifold.

Disconnecting it should make the car go in to limp mode but it will only do it when it tries to open the valve so engine hot and a reasonable amount of throttle. EGR valves are over £400 fitted by the dealer, they can be removed and cleaned but you need to get under the car to undo the retaining bolts and it is not a straightforwards job.

My suggestion, remove the engine cover, look at the inlet manifold there is a sensor closest to the cylinder head, held in place with an 8 mm nut  (two close together) remove the sensor and clean it (gently) reconnect the EGR see if you still have a problem.

[mseh1971]

i have cleaned the inlet manifold sensor did that the other day with the air flow sensor, the egr valve mine has a brown plug on it with a purple insert 6 connextions in it manage to take egr valve off no need to get under car tools required 10mm socket and rachet 10mm spanner and a 8mm spanner un did the 2 10mm bolts on top of the valve that discoonect to nice shiny pipe that goes over engine.next 2 10mm bolts on the side of valve that disconnects it from the water cooler then its 2 8mm bolts that are about 3 inches long that go the center of the egr valve.un pluge it and remove from vechical. manage to clean it and to find out the valve was slightly sticky manage to take it out and complety clean it.put it all back together now to put it back on the car start with the water cooler end first dont forget to put the little metal gasket with it to 10mm bolt in leave loose then do your 3 inch 8mm bolts now tighten all your bolts up plug it back in then do the 2 10mm bolts that do the shiny metal pipe that goes across engine manage to do that just over a hour. good news is cars runs fine no hesitation in low revs down side is now i have the little yellow engine on and computer saying anti de-polution faulty question is now does this car have to go to the garage to get yellow light to go out.as it wasnt on before when the car had a fault now i fixed the fault now the car is saying it has a fault any help will be much appreciated.

[qman3428]

Two things to try, first start and stop the engine 4 times. if the light goes out job done, if not Try rebooting the cars computer

The correct way of rebooting the car is to open the drivers window, close the doors with all accessories turned off and have the bonnet open,disconnect the positive connection on the battery for at least 3 minutes. Reach through the window and turn on the side lights and leave it for at least 15 seconds. Insert the key through the window and turn the ignition on (dont start the car) hold down the lock button for 10 seconds. Remove the key and check the doors lock and unlock. Turn off the sidelights, shut the bonnet and close the window, start the car and reset the clock. You have just rebooted the cars computer. Hopefully that will reset the engine light.

[mseh1971]

Thank you very much we done what you said we are a little bit slow this end! It took two attempts, second time by the stop watch to re boot the computer and it worked like a charm. This car has had thousands spent on it even a new engine; to try and get rid of this fault. And it turned out to be just over an hours work getting my hands dirty following this web site, and its done!! This car has been at a main Citroen dealer in Cambridge several times and to no avail. And yet been on this web site not even 24hrs and the car is sorted.

 

Many Thanks

qman3428