Hello all,

I have recently purchased a used 2001 V40 January of this year. The engine is gasoline B4204T3. Since buying the car I have had problems with cold starting. The engine seems to crank well but does not fire and runs rough until warm if it does start. If the temperature is a few degrees above zero celcius it is likely to start though still very hard. If the temperature is below -8 celius it will not start. We have had it in to the dealer and the fuel regulator and spark plugs have been changed with no improvement. The positive crankcase ventilation hoses and valve were apparently plugged and were changed also with no improvement. They also found that the oil was a little sludgey and did a couple of oil flushes.

Based on other posts on this forum where people had problems with the idle air control valve I tried starting the car with it removed. The valve opened while starting and then closed and while a little dirty didn't seem to be gummed up. Taking the valve off did not improve starting.

A compression test was done by the dealer (I assume while the car was warm) and all cylinders were around 130psi. A leak down test was also performed (when cold) and there was significant leakage into the crankcase. I have also noticed a bit of steam if you pull the dip stick immediately after starting. The dealer has suggested that the rings are carboned so that they do not form a good seal when cold. The theory is that this lack of seal prevents the car from starting when cold but that the rings loosen up when warm. The engine seems to run fine once warm. The dealer suggested putting 500-1000km of highway km on the car with a fuel system cleaning additive to clean out the carbon.

Does this seem a reasonable explanation and has anyone had a similar experience that was solved by highway driving (or otherwise)? Any suggestions of the best way or specific fuel additives to get the rings clean? Any advice appreciated. I will post our solution when we find it.

Thanks,
John

 

Try cycling the key like 4 or 5 times before starting and see if it is better.
If so then the fuel pump might be bad.

 

Thanks Tech, Just gave it a try. I could hear the fuel pump whirring with each cycle but no improvement with starting.

 

Maybe coolant temp sensor or thermostat.

 

Good ideas but I don't think it is either. I have a code reader that can report some live data and it seems to report the coolant temperature accurately before starting. The temperature comes up reasonable quickly after starting and is stable around half scale on the gauge while driving.

 

If you can find a fuel pressure guage that you can install and leave on for a while try it and see if the fuel pressure drops to 0.

 

For the record the Volvo dealer here pulled the engine and found the liner cracked in the fourth cylinder. They did not disassemble further to find the condition of the rings. Engine was replaced under warranty and seems to have solved the cold starting problem.