Rough Running From Cold

[Tuscan1969]

Hi There – I hope that you can help.

 

My 2003 C5 2.0 16V SX manual petrol (showing about 50K miles) frequently displays the catalytic failure and anti-pollution failure modes….these come and eventually go so I don’t intend to do anything about them at the moment. Similarly I have the fault in the COMM 2000 module that leads to the airbag fault warning but I am prepared to live with that too.

 

However recently it has been acting up in a different way. Immediate starting from cold the car is fine. However within a few yards of setting off it begins to run very rough. Water temp begins to rise but the oil temp stays low and then most time the catalyst fault gets displayed. The rough running gets progressively worse for the first 5 minutes and will occasionally result in the car cutting out when the clutch is fully depressed. The car will re-start easily but still runs very rough and the failure light stays on. The water temp seems fine but the oil temp gauge is very slow to move up and never seems to get to the mid-point properly. As the engine full warms through the running gets a bit better (and if it’s a long enough run it ends up running fine but the warning light stays on). Starting again later on with the engine still partially warm the car is usually fine. It’s recently been fully serviced and all filters etc were changed. It does not do this every day but its noticeably worse in cold and/or damp weather. Yet on a recent long motorway run it performed perfectly.

 

I am hoping its something relatively small like a faulty Oil temp gauge, or maybe just replace the fuel filter. I use the car mainly on short runs (my commute is only about 5 miles) so does the engine need a flush – or is it something more fundamental – I have seen that there may be cold weather starting problems if the air pump is faulty????

 

Any help is much appreciated.

 

PS for the last two days when I leave the car the suspension has dropped completely flat but only at the back of the car not the front - it levels back up when I open the car but I have had it for 3 years and its never done this before....whats up????

 

Cheers

 

Tuscan1969

[seefive]

Hi There – I hope that you can help.

 

My 2003 C5 2.0 16V SX manual petrol (showing about 50K miles) frequently displays the catalytic failure and anti-pollution failure modes….these come and eventually go so I don’t intend to do anything about them at the moment. Similarly I have the fault in the COMM 2000 module that leads to the airbag fault warning but I am prepared to live with that too.

 

However recently it has been acting up in a different way. Immediate starting from cold the car is fine. However within a few yards of setting off it begins to run very rough. Water temp begins to rise but the oil temp stays low and then most time the catalyst fault gets displayed. The rough running gets progressively worse for the first 5 minutes and will occasionally result in the car cutting out when the clutch is fully depressed. The car will re-start easily but still runs very rough and the failure light stays on. The water temp seems fine but the oil temp gauge is very slow to move up and never seems to get to the mid-point properly. As the engine full warms through the running gets a bit better (and if it’s a long enough run it ends up running fine but the warning light stays on). Starting again later on with the engine still partially warm the car is usually fine. It’s recently been fully serviced and all filters etc were changed. It does not do this every day but its noticeably worse in cold and/or damp weather. Yet on a recent long motorway run it performed perfectly.

 

I am hoping its something relatively small like a faulty Oil temp gauge, or maybe just replace the fuel filter. I use the car mainly on short runs (my commute is only about 5 miles) so does the engine need a flush – or is it something more fundamental – I have seen that there may be cold weather starting problems if the air pump is faulty????

 

Cheers

 

Tuscan1969

 

I had exactly the same problem on my old 2002 Mk1 2.0 petrol sx (non hpi)

 

After numerous passes, incuding changing the coolant temp sensor, it was diagnosed by an engine diagnostic specialist as a sticking valve. The car wasn't worth enough to spend the kind of money necessary to prove that, so I lived with it. Hydraulic lifter cleaner added to the oil helped to calm it down, and made it tolerable.

 

Oil temp never gets to the middle of the guage - my current late model Mk2 is eactly the same, as are the Peugeots which have the same oil temp guage. Nothing to worry about there.

 

Main dealer told me the air pump was faulty, but I could hear (and feel) it working on start up - so be careful with that route. Could be an expensive waste of money.

 

Good luck, don't spend too much on it - second hand C5's are not exactly valuable!

[Tuscan1969]

Many thanks for the advice - I'll try that! As its just got through the MOT I'll hang on till its ready for scrap!