Hi everyone, i have an 2001 2.0t s40 165cv engine b4204t3, lately it's been misfiring, first at cilinder 3, than and now repeatedly a cilinder 1, the spark plugs were changed 5000kms ago, also the ckp. the engine is throwing p0301 code and ecm 44 codes even when erasing. The coils seem to be in good condtion even when swapped the problem didnt dissapear. Any idea where the problem could come from¿? Thanksk in advance guys

 

your car has two coils each with a spark plug wire to the second cylinder. Check date codes on the wires. Also inspect the wire harness that goes from the firewall to the coils. pretty common for the connectors at the coils to crack and arc out. Some people have had luck sealing up with RTV or similar but I'd recommend replacing the harness. Any other symptoms like long cranking at a cold start first thing in the morning? If so you may have an issue with the fuel pressure regulator that sits on the side of the fuel rail. Pop off the S shaped vacuum line - if any fuel drips out, you have a torn diaphram and its time to replace the FPR. As to the spark plugs - did you use to torque wrench to properly set the plugs and did you use OEM style plugs? These cars don't really run better with triple iridium blah blah blah as those style plugs were designed for newer cars with single coil/cylinder. Best to stick with OEM or genuine Volvo plugs with the single electrode.

 

after making changes and swapping between coild spark plugs and stuff i havedetermined that is not ignition related, cause i bought even a new wiring harness for the coils and still gets misfiring at cilinder 1, so the next thing to check are the injectors i gues and the crankcase breathing sistem. I'LL KEEP YOU GUYS UPDATED

 

You also check fuel pressure? when my FP regulator went, it had long cold cranks and threw misfire codes. any signs of a loss of power? a compression/leak down test may be in order to check for a possible burnt valve

 

Fuel pressure regulators are a common replacement item on the 4 cyl - is there any fuel in the vacuum line at the regulator?

 

Not sure if you are actually switched the coils themselves.If you just did the wires that might not show changes as the problem is in the coil itself most of the time even for the cylinder with the wire.Got to swap the coils.

 

Every time mine misfired it was the coils and wires.

Extended cranking was the fuel pressure regulator.