'99 V70XC Changing Spark Plug wires

RichSad · Post by **RichSad** » 01 Sep 2010, 17:32

I wrote about a P0303 code the other day. Following advice on this forum, I performed some tests and was able to determine it is not the spark plug or ignition coil since plugging in a different wire (from cylinder 2) into cylinder 3 correctly fired cylinder 3 and the error moved to cylinder 2 (which was unplugged).

I suppose the most likely culprit is the wire that runs to the cylinder. I am a little unclear whether my turbocharged 2.4L has a distributor or not. I can't seem to find pictures or instructions. I see there is a clump of wires that go under the aluminum cooling thingy and then go to each cylinder. It looks like it would not make sense to replace just one wire but I'd need to replace all 5. How do I do this job? I've replaced spark plug wires in the old days on big old American V8 with distributors, but I can't even see anything that looks like a distributor on this engine! Can anyone help a newbie? Would local autoparts stores be likely to have the parts I need?

One parting thought: if I fix the wires and cylinder 3 continues to misfire, what is the next component up the electrical chain that could be to blame? If there is a distributor, is it easy to replace? Again I replaced a distributor once decades ago but not on a newfangled European engine!

FCPEURO · Post by **FCPEURO** » 01 Sep 2010, 18:16

As for as I know, the 99+ model XC70 does not have a distributor. Each cylinder has it's own coil pack so more then likely, the coil on cylinder

Post by **Pauloil** » 01 Sep 2010, 19:53

I'm not sure what you proved with your experiment. i would think an unplugged coil pack would give an error.
commonly the pack goes bad and not the wiring. as I suggested, unplug the injector, to comfirm the bad cylinder pack. If the motor runs worse, i.e. on 3/5 cylinders, then assume that coil pack is OK. now, you have a code reader. It said 3 was bad. for fourty bucks you can sub a new coil pack and probably fix it.

RichSad · Post by **RichSad** » 02 Sep 2010, 04:55

Sorry, I'm not sure what you mean "unplug the injector" The experiment I did seems pretty sound (it was suggested on another auto site). If I plug the wire in for cylinder 2 into cylinder 3, cylinder 3 fires correctly and cylinder 2 is the only error. This seems to pretty clearly prove that the ignition coil and spark plug in cylinder 3 are OK.

I certainly could replace the ignition coil in cylinder 3, but I know the ignition coil isn't the problem since when connected to cylinder 2's wiring cylinder 3 seemed to fire OK. The error code switched from 303 to 203 and there was only one error, indicating that indeed cylinder 3 fired correctly I think.

I certainly have nothing against investing $40 to try to fix it, but it really seems to me my logic for thinking the coil and plug for that cylinder are OK.

Post by **Pauloil** » 03 Sep 2010, 16:57

pull off the aluminum cooling sheet on the fuel rail
the injectors are underneath and you can unplug them one at a time if you don't have a code reader to tell you what is wrong.
so if coil pack 3 is bad, unplugging injector 3 will not change the way motor runs. unplugging 1,2 or4,5 will change it.

Allen in Hemet · Post by **Allen in Hemet** » 04 Sep 2010, 16:22

You probably have an ignition coil for each cylinder, no distributor, no spark plug wires. The coil sits right on top of the spark plug. One ignition coil per cylinder. The way I found which ignition coil was bad on my 2000 v70xc, i unplugged the three wire connector at the side of each coil, one at a time. the bad one will make no difference in rpm, when you unplug a good ignition coil, the idle speed will momentarily drop, then come back up, as the computer likes to maintain a set idle speed. By the way, I ended up replacing all five over period of 3 months, shortly after I bought the car last fall. Some were my fault, they got wet inside when cleaning the engine. $50.00 each at Autozone.R/ Allen