C5 2.2hdi turbo over boost?

[phil1969]

hi, i'm new to citroens, just bought a C5 2.2hdi exclusive. i'll start with the things done so far, suspension leak fixed parts replaced. DPF removed and ecu remap as anti polution fault on dash. but still has the anti polution fault on dash and engine and service light on by the clocks plus in limp mode can't go over 2500rpm, has been checked and the fault code is turbo over boost. where do i start EGR valve off and cleaned, check pipe work to turbo? read alot of posts on here about this but thought i'd put my own on here too.

hope you can help.

Phil

[woodywoodpecker]

Phil,
Check the swirl valve is working its located on the right hand side of the cylinder head as your looking under the bonnet, you are looking for a long thin rod with plastic ball cup on the end and it connects to the intake butterflies. Its a common fault with the 2.2hdi when you start the car the rod should move fully backwards towards the windscreen and when you rev the car it should come forwards. A few i have seen have come off the ball it clips on to, if its connected and not moving you have a vac leak. Check this first and let us know.

[phil1969]

will do, cheers.

[phil1969]

right... checked the rod and its connected but it stays where it is when the car is started and moves towards the windscreen when revved. doesn't move hardly when lightly revved. hope this helps. forgot to mention that the lights on the dash and the anti polution fault go off at times but will come back on when accelerated to 3000 or over it'll kick back on.

[waynedance]

Hi I have same engine and I believe my swirl thingy works the same goes towards windscreen when over approx 2000 rpm.

[KevMayer]

The swirl butterfly actuator should open at 2100 rpm. So, that's working normally.

There are 5 actuators on a common vacuum system (aswell as the brake servo ). The fact that the swirl butterfly is operating ok suggests that you don't have a vacuum leak. A vacuum leak can prevent the actuators from working which is the usual culprit for turbo overboost.

The turbo is designed to give maximum boost when the controling vacuum actuator is inactive. This means that, if the actuator isn't working, there's no control of turbo boost pressure and when you put your foot down you get overboost right away.

The problem is probably with the turbo vacuum control electrovalve. It lives on the bulkhead under the plastic cover by the passenger side suspension sphere ( assuming it's a RHD C5).

Theres a vacuum in pipe, a vacuum out pipe and an electrical plug.

Next to the turbo electrovalve I think it's the EGR electrovalve. Perhaps you could try swapping the connections to the EGR electrovalve and take the C5 for a run. I'm not sure this is actually possible, but, it's worth a look.

[cachaciero]

Little bit of clarification, the turbo actuator and the swirl valve actuator are fed from their own vacuum subsystem with it's own resevoir. As kev points out with no vacuum the turbo is in max boost mode. The problem is almost certainly, a problem with leakage, and on older 2.2 holes in the swirl valve diapraghm causing variable vacuum leakage is almost a certainty, the rubber joiners that join bits of the vacuum pipe are also a known problem.
The proper way of checking this is measuring the vacuum. This has been well covered in these forums, do a search on swirl valves and my name and you will find this topic covered in some detail.
I would say that the problem is unlikely be due to the electrovalve but I would put money on a swirl valve actuator with a diaphragm full of holes
cachaciero

[phil1969]

thanks guys will look into it. full day on it tomorrow. i'll let you know.

thanks again

Phil

[phil1969]

Right, the car is sorted! Completely different motor. The fault was the swirl valve, the rubber had a couple of small pin holes in it when I inspected it.£23 on ebay, fiddley job but done. Also found the plastic T piece next to the butterfly valve that the bar of the swirl valve connects too was loose. Only held on by 1 10mm bolt, put a new rubber O ring on tightened back up. No more fault codes.

Thanks for all your help.

Phil

[waynedance]

Glad you sorted it, £23 from ebay!! I am sure I paid less at the dealer.

[corsehf]

I paid £16 from the Main Stealers! - makes it worth calling them once in a while - you never know!