Hi all,

I have a 58 plate cooper S with 20K miles. Today I decided to service it myself and did the following steps:

Seafoam - Heard good things, used about half the can through the brake booster pipe as per youtube. Car worked fine afterwards on a 10 mile round trip to halfords and back.

Two hours later, an Oil and filter change - Changed the oil, replaced with Castrol edge 0-W30, car only took 4l before showing just above the top level (Hard to tell when filling cold) - Not tested after

Spark plug change to JCW iridium plugs

Now, I drove down the road all ways hunky corey for 1000m, felt sharp and more powerful than before. Started going up an incline and suddenly, a horrible bumpy engine, and a yellow warning light. Managed to drive it back home, but it sounded like I was down a cylinder. I opened the bonnet, and took the coils of one by one. Each time a coil was taken off whilst running it sounded worse until cylinder 3. Took the coil off, and no change in noise or idle. I changed the spark plug back to the original, no change. Changed all the spark plugs back, no change still an awful sound and no power and warning light.

Im pulling my hair out, i wanted to do good to my car not cause issues!! What could be wrong??


Thanks,

Dave

Hi Dave

Could be an issue with the ignition coil. Try swapping the coil with another cylinder, then repeat your previous diagnosis of unplugging each coil one at a time.

Another posssible issue with the R56 Cooper S is the timinig chain tensioner. This is an oil pressure controled tensioner. The issue could be to do with a lack of oil in the engine so check the oil level is correct.

After that you'll be looking at possible timing jumped, high pressure fuel pump, or 'coked up' inlet valves. Hopefully it'll be an easy fix. Any further info just ask!!

Hi

You need to plug it in to a diagnostic machine pull down the code.
If your a member off the AA or RAC or simalar get them to come out find out the code or if you have a mate with a code reader.
Like chrish says it could be the coil pack, but it could be a lot of other things as well.
When you have that coil off put an old spark plug in it and make shore it's sparking
You could have a bad valve, injector, crankshaft/camshaft position sensor, fuel pump the list goes on get the code and see what's the problem is

Thanks for your assistance with this. Mini assistance came out during the snow (in a brand new 530d!) and immediately found a faulty coil and replaced it within 30 seconds. (caused by me yanking it off at a strange angle as the wire to it is very tight, the online tutorial for changing plugs didnt enlighten me that the wire to the coil is quick release allowing you to pull it straight up and not break the rubber end of the coil) New plugs are on and I have to say the car now feels excellent, definitely back to how it felt after the p-torque remap if not better. All in all well chuffed with what difference an oil change, seafoam and plugs has made for my car. Thanks