WTF after plug change...need suggestions...

[carboncow]

I'm sure many will argue plug choice but may some others have an idea of what can go wrong with doing plugs in a 2001 T5, as this was not the funnest plug change!

Runs rough now after plug change, cannot tell if it's one is not firing. Haven't put on road yet as the idle alone is concerning.

I got the plugs recommended FCP Groton, Bosch Platinum Plus. I've read many online say they use these plugs.

2001 T5 130K miles, running fine before swap.

All wiring looks good to the DICs although the protective conduit was dry and cracking. All DICs seated well. Although the plugs were difficult (read scary) to get out the new ones went in just fine...

Gapped to .028 per several threads I"ve read, but now I"m re-researching to see if I can find different data specific to a T5.

EDIT: OK All is well now. I went back out to check everything, started it up and took it around the block and as smooth as a babies bottom. Adaptive driving for plugs!?!?/

[T5AUS]

Wow, the more I get to know these baby's the more un car like they seem, it's as though they have minds of their own and will not be rushed. It's a bit like trying to coax a kid into behaving by offering it incentives. I find myself whispering (as I climb into the car for a mornings drive in to the city) "I promise I will take you on a long drive next weekend if you dont play up this week" "I might even treat you to a car wash and shine if you are really good" My old 850 T5 is never this moody

[carboncow]

We'll the spark plug topic is very much one of those "hot points" that is a bit odd. Many say anything but Volvo will cause issues and an equal number say they have been running product "x" just fine.

I come from a long line of Saabs in my family and this is the first Volvo. Equally as happy but there are a few unique issues!

Saabs are also hot running turbos minus one cylinder...but everything should be the same. Getting the plugs out of this Volvo was an amazingly nerve racking procedure. I'm not talking about the annoying intercooler hose DIRECTLY over the torx bolts to the plug covers (and I didn't mention the stripped torx holding that tube to the engine) but the fact the plugs were so "stuck" in the cylinder head I really was sure something bad was going to happen. Cannot figure out why so many procedures say to put antisieze on the new plugs as in 20 years of Saabs, BMW and Porsche...I never needed it...but I did this time knowing how difficult the plugs were!

Took for 2nd drive and the shutter issue is gone. case closed.

[carboncow]

EDIT: Looks like the rough idle reared it's head again. After driving fine for a some time it feels like it's missing. Going to find some copper core plugs tomorrow and waste some more time!

Should I be checking the DI units or would they be tossing codes if they were bad?

[matthew1]

Check that the plug wires are on good, just give everything a good wiggle. Also, look at the engine while she's idling in the dark, perhaps there's arcing from a wire to the block. Those wires get brittle after a decade.

[carboncow]

Great ideas. I'm going to have a patient evening with the system tomorrow. The more I sit here the more I simply cannot believe the plugs are to blame!

[RaymanSean]

It could but with the modern electronic ignitions it takes a lot to make a spark plug cause issues. I would place my bets on a bad connection or a intermittent coil. Spend some time with your patient and let it tell you what is wrong.

[carboncow]

It's always fun with they get old and brittle and when you are just trying to treat them nice and fix them all those neat little electrical connections get funky!

I"m re-thinking the connection with the coil and the plug. Most cars I've had with a coil have a noticeable "connect" with the tip of the plug as it grabs it...I don't recall this.

I thought I saw before a procedure on how to test the coils with a ohm-meter but I"m not seeing it. Anyone got a procedure if I have to get that far? Seem to recall reading a thread were one coil was a bit "off" w/o being dead.

[ed7]

Start by reading the plug to find the problem cylinder then if you don't find a definitive test for the coil, compare with another coil. The plug will tell you a lot.
Ed

[carboncow]

OK, here's an update for those that care or future me(s)...

With the cover off (prior to removal of the plugs) and with the intercooler pipe back on I started the car with a rough idle as if one cylinder was off...there was an "odd" throaty sound to the exhaust...this won't do. I noted there was no arcing with the lights off in the garage.

I took apart the top end again down to the plugs one by one reviewing the connections, wire placement, gap and putting it back together with equal care. Not one item stuck out as "off" and all wires were neatly tucked under the cover w/o any concern of pinching.

but...

This time I torqued the plugs to proper spec 18.4 ft lbs is what I found with a "good" wrench I brought home from work and I seldom trust my cheapos. I have to admin I tend to torque plugs by hand due to the concern of stripping. All heads have a different feel and a prefer my method as in 20 years I've never had much a concern on Vw, BMWs, Porsche and Saab...

well...this may be the concern. The plugs seemed loose when I took them out and I torqued them to spec which seemed WAY beyound what my "by hand" technique delivered. Car idled just fine.

Tomorrow I will take it for a couple mile run to get it up to temp (about the same run as the night before). I guess one could argue that improperly torqued plugs could allow for compression concerns especially after a good warm up. If this doesn't solve the need I'm going to have to go the coil check route but my experience with coils is they tend to work or not...and usually throw codes, which I don't have.

OK, bring the "duh" comments but as stated in 20 years of torquing plugs by hand, I'm not sure I've had this concern before! That is the best guess I have right now...