Spark plugs and misfiring

marcus · Post by **marcus** » 22 Sep 2019, 05:08

Hello,
I have volvo s60, 2.4 170 hp. Since some time I have multiple cylider missfiring.
I did check today spark plugs. IIdid check 3 of them. Long electrode have more or less colour on it. Does it mean enything? I made on them aprox 15k miles. I am runing my car on propan butan. It is using gasoline on stratup and heat up.
Please see the pictures.

Post by **abscate** » 22 Sep 2019, 06:03

Those gaps look a big big, they should be 0.7mm (0.028 inches for Yemen and the USA)

I don't know how that varies on a propane car, though

Post by **- Pete -** » 22 Sep 2019, 11:52

Ignition coils would be another natural place to investigate. Oodles of people with 2.4T/2.5T coil failures.

Can you share more about your Propane setup?

Post by **oragex** » 22 Sep 2019, 14:22

I'm guessing this is an LPG car with the non turbo 2.4 gasoline engine. I'm not sure if converting to LPG will require different spark plugs, but for the standard 2.4 NA engines running only on gasoline, these are not the correct spark plugs. The right ones look like this, with 3 or 4 prongs (these are not the exact part number for the S60) https://www.rmeuropean.com/Images/BigPi ... FG14-2.jpg

Your spark plugs look impressively clean at the tip, perhaps due to the propane cleaning properties. Yes the threaded part is darker, but the tip is very clean. Try first testing the ignition coils, and also make sure to verify you got the right spark plugs. If needed replaced, use only Bosch ignition coils www.youtube.com/watch?v=fnYUQh23p7Q

Not related but while there, be sure to also test the intake air thermostat, may search on Youtube