Temporary loss of power

[Teapot]

Hi all,

I have a 2004 Signum CDTI 120 with about 110k on the clock. Since I bought it about a year ago it has performed well, but yesterday it lost nearly all power below 2000rpm. Above 2000 was fine but needed more throttle than usual.

I gave it a good thrashing along a stretch of dual carriageway with several roundabouts and cruised at 70 in 4th instead of 6th for a while to keep the revs high and get the engine really warm, and the problem seems to have gone away. There were no warning lights on at any time.

Having read various other threads on this forum, a failed EGR valve or swirl valve (not sure what the latter is or does) seems to be the most common cause of these symptoms. However the previous owner had the EGR and manifold replaced at a vauxhall dealer (over £700!) not long before selling it. Could the new one have started getting clogged already? If the fault comes back, what should I look for?

Also, the engine is a little bit noisy when cold, has been for several months. Sounds like a faulty tappet but can only hear with the windows down. Once the engine is warm it sounds fine. Need I be concerned? It's a little quiter since having the oil changed, but the noise is still noticeable.

cheers
Paul.

[nokiaman1978]

does your car have dpf if it does by the way you have driven your car it has caused it to regen and burn away the soot which is a good thing.

[Teapot]

does your car have dpf if it does by the way you have driven your car it has caused it to regen and burn away the soot which is a good thing.

Yes, it does. I often drive quite enthusiastically anyway, plus it had a couple of 200+ mile motorway runs in the last few weeks so I'd be surprised if the dpf had got clogged up.

cheers
Paul.

[barney490]

hi Paul,

If yours is a 120, it wont have swirl valves, these are only on the 150's. Has the car covered many miles since the EGR was changed? might also be worth a visual check of all vacuum hoses and clean the boost sensor. I have a 120 estate with 104k on the clock and the boost sensor was virtually blocked with soot and crud. the egr has to be removed to gain access to fixing bolt of the boost sensor. Mine is also a little noisey when cold but fine when warm, so given the mileage, i dont think its a concern.

[Teapot]

hi Paul,

If yours is a 120, it wont have swirl valves, these are only on the 150's. Has the car covered many miles since the EGR was changed? might also be worth a visual check of all vacuum hoses and clean the boost sensor. I have a 120 estate with 104k on the clock and the boost sensor was virtually blocked with soot and crud. the egr has to be removed to gain access to fixing bolt of the boost sensor. Mine is also a little noisey when cold but fine when warm, so given the mileage, i dont think its a concern.

It's done about 15k since the EGR valve and manifold were replaced. If it goes wrong again I'll check the boost sensor and EGR valve.

Thanks!