'01 S80 T6 P0303

FA-18Boog · Post by **FA-18Boog** » 02 Jun 2012, 13:33

Out of the blue our 2001 S80 T6 started running rough at low RPM. Pretty good vibration and feels like is is just bogging down. CEL flashes and then comes on, P0303 code is the only thing popping. Replaces all plugs and changed coil from 3 to 1 with no change. All of the filters are new, checked all vacuum lines and they are good to go as well. The car up until then had been running perfectly... The wiring to the Coils looks fine - where do I go next?

How do I access and/or test/clean injectors? I would like to solve this myself, but am about to throw in the towel.

Post by **dcarlson12** » 02 Jun 2012, 22:14

Are you saying you changed the coils to new ones on cylinders 1,2 and 3?
That code is specific to cylinder 3. Or did you move the coil from cylinder 3 to cylinder 1 to see if the misfire moved over to cylinder 1 from 3 as a test?

FA-18Boog · Post by **FA-18Boog** » 03 Jun 2012, 09:42

Sorry - based on the code (as you pasted) my assumption was that it was a plug or coil related issue (from reading numerous other posts). All plugs were changed - nothing obvious noted with their condition which makes sense based on the new change in misfires. I purchased a BERU german coil that is identical to the Volvo coil and installed with the plugs. All connections and wires "look" good. AFter buttoning everything back up the same running characteristics and P0303 code persists. I went back in and swapped the #1 and #3 coil to see if there would be any change - none...

Others have suggested swapping injectors - am not sure how to do that - could not find a good DIY or would try. I am "reasonably" competent, but this has me scratching my head.

Post by **mikealder** » 03 Jun 2012, 10:15

What state is the wiring that goes to the coil pack on number three, especially the bit under the cover as this usually gets hot, if it is shorting out to the engine block then it could be this that is causing the missfire - Mike

Post by **dcarlson12** » 04 Jun 2012, 17:15

I am pretty sure you just have to remove the cover over the injectors and then you can access the injectors and maybe move one from a non misfiring cylinder to the misfire locations and vice versa?

FA-18Boog · Post by **FA-18Boog** » 06 Jun 2012, 18:35

OK - both feel the fool and relieved. After chasing my rear on this it just did not seem likely that a fuel injector would be the culprit without throwing out an additional code. Pulled everything open and found that in replacing the plugs, I over torqued cylinder 3 and broke the plug. That is why I still had the P0303 and changing around coils had zero effect.

I often have to relearn that it is almost always the most likely issue is what you have to resolve 1st. By backtracking and starting from square one this was a 20 minute fix vice breaking down my fuel rail and injectors and creating a larger mess.

BTW while doing this I managed to strip out my air intake hose bolt where the turbo tubes attach. Luckily I know a local who is parting a 2002 S80 T6 and I picked up the intake tubes and fuel rail with injectors for $45 all in immaculate shape.

Thanks for the help - love the board.