C5 No boost at all!

[brown999]

Hi everyone...

I have just signed up to the forum, wish I wasn't having to ask for advice immediately. After being in a car accident last week and loosing my Volkswagen I decided to buy a Citroen C5, its a 2003 2.0 HDi. On the test drive it was spot on, I really searched for problems but it was great for what I wanted and a bargain price. So I bought it and off home I went.

Anyway the next day I went out and while I was driving it felt funny, as in there was no boost whatsoever from the turbo. It still drives fine but it is just lacking the energy that the turbo gives to this big car. I have no idea how in the space of a day this has happened? From what I have read many people have encountered this problem but I am a bit stuck with it. The engine management light has also not come on which I thought would have.

Upon searching through hundreds of pages online, many of which are from this forum I am just stuck. I was able to dig out one of them little ODB scanners from an old car which gave me several fault codes...



I have had the intercooler pipes off this evening and inspected them for any damage of cracks but they are immaculate. I also took off the MAF just to check but it is also very clean and healthy looking.

The only glaring problems I found on inspection were a few wires that the coatings were completely worn off, I thought that these could have been causing some issues so I cleaned them up and re-insulated them...

http://tinypic.com/r/2uhlqut/9

http://tinypic.com/r/2m5gvnn/9


If anyone has any suggestions for what I should look at next please let me know

Thanks Steven

[Peter.N.]

Try running it with the MAF unplugged.

Peter

[brown999]

I tried running with the MAF unplugged, didnt notice any difference at all?

[BX]

Erase all the faults. See which ones will not clear or will come back very quickly. Ignore the glow plug one.
Look at the live data. See if anything seems astray, in particular manifold or boost pressure.
If you get a series of boost related problems back after a short drive.
Check f15 in the underbonnet fuse box. Check that the 2 solenoid valves (egr & wastegate) are connected and have a 12v supply. Check the resistance of the coils, 20 ohms. Check the vacuum pipes on both if these. Check that the vacuum actuators are not leaking. Check that the wastegate actuator can actually operate by applying vacuum to it.

[dnsey]

It looks likely that either the wastegate vacuum solenoid valve or its associated hoses have failed - not uncommon.
If the hoses are intact and connected, try temporarily swapping the EGR and wastegate solenoids.

[citroenxm]

Under the plastic cover over the passenger strut there are three electro vaccumm valves.

one for waste gate
one for egr
one for butterfly flap on intake.

the turbo has to have a vaccumm on supply to wastegate for it to work. They default to open wastegate and so no turbo boost.

running an engine without the maf will put the eml light on which will need a lexia to reset it.
dont worry about all the faults read you dont know how long they have been there.
follow the vaccum pipes to find the electro valve that leads to the turbo

replace with another one they are about 30 quid on ebay.

This is useually the problem with the 2.0 ..

[Gibbo2286]

Before you spend money on electrovalves etc. make a very careful and close examination of the thin rubber vacuum pipes on those valves and down to the turbo actuator, the smallest split will be difficult to see but will stop the turbo working.

[Monkeyfeet]

Not sure about the intake swirl valve on the 2 litre?
Anyway re the electrovalves. Definitely worth swapping after checking hose condition. Blue plug and hose markers for the EGR &, other one to the turbo? (vac pipe runs down, LHS, drivers side of cyl head)
MAF connected /disconnected making no difference is also significant isn't it?
Well done with the wires BTW. Was it the engine covers rubbing on them?

[citroenxm]

Yes on c5 and very last Y reg 2.0 hdi a swirl valve flap was added at the inlet manifold!! So on c5s there are three electrovalves..

[Monkeyfeet]

Ah... Cheers!
Did they ever get around to other models too, or was it just the C5 do you know?
(sorry for digressing slightly)

[brown999]

Guys thanks for the replies.
I'm going to check through theses ideas this evening after work.

Hopefully I can find something, diesel consumption has went through the floor plus I have to drive up a great big hill to get home and it is sketchy without a turbo

Will post back with results!

Thanks

[brown999]

Managed to have a look at the car for a while today...

I found the 3 small pumps underneath the cover on the left hand side of engine bay, I traced all the pipes and as far as I can see they are in great order?
With the car started I took off the vac line that leads to the butterfly valve at the end of the intercooler pipe. When i removed the vac line I could feel a small amount of suction but nothing drastic, when I put it back on the pipe I watched the butterfly valve close and immediately open again?

Is this normal behaviour?

[citroenxm]

Yes.. that be the ecu controlling it.

its the one that's goes down the back of the engine that needs to work trace it back to the valve and check vaccuum at the valve.. there should be one at idle... wastegate default to open so no boost so it needs the vac to close it...