It was time to replace the worn out oem clutch, so I bought an RPS and had it installed by a local and reputable import shop. Also had the flywheel resurfaced. Clutch works excellent, very responsive, but now I have a misfire problem and can't figure it out.. Regardless of what gear, I have a "miss/skip" between 2200-2800 rpm, but no cel.. and it's very noticeable. It goes away though if I accelerate but that is not the main issue. When I start to hit full boost, and it only seems to do it in 3,4,5th gears, the car starts bucking/sputtering and losing power bigtime.. I get a p0304 cel every time and sometimes a p0302. I have checked the plugs, and they are a light brown, almost rust colored (they are iridiums), not fouled or ashen and still gapped at appox .028. I don't see any loose connections or broken wries/couplers. I went back and tightened all clamps (I have a FMIC) and couplers to make sure it wasn't a boost leak.. but I'm running out of ideas. I suspect maybe the cam sensor, or possibly slop in the timing belt tensioner, but I don't know. Any ideas/info would be greatly appreciated. Btw- the car starts and idles very well and smoothly, and remember, this only happened AFTER the clutch install, and I've changed nothing except plugs since then. I have a Cobb AP with an SS custom map, but I don't think it's map related.
I remember the Siegel mentioning timing problems with lighter weight clutches. Is your new clutch lighter?
so did you install a lightweight flywheel or not. maybe you should take it back to the shop who put the clutch in if it started after they did the work
^^^He only had the flywheel resurfaced, but the clutch is aftermarket. To me, it sounds like the area right where your power starts to come on. Have you given your clutch time to break in? Its supposed to be like 300-500 miles of light driving to get the clutch disc seated properly. Another possibility is that the flywheel surface may have some dirt or grime on it and that is causing the slippage. Either way, if it doesn't go away in the 300-500 miles, then go back to the place you had it installed.
I don't see why a lighter clutch would cause any timing problems. To me, it seems no different from running lighter wheels. The flywheel and pulley are a different story.
hmm..i was going to suggest the flywheel was the problem but if it was only resurfaced that shouldnt be the case unless they took a substancial amount off of it. I would take it back to the shop that did the work.
here at classic we do not resurafce flywheels at all. we just clean them up with a die grinder if there are no big divets or scratches or heat marks. otherwise we replace it. what about you guys at SOG? does SOG resurface flywheels? have you checked the coil packs for any corrossion built up in the terminals. i have seen that a few times
^^ yeah, the coils seem to be fine, and I installed new plugs also. The flywheel is stock, and the machinist only took a minimal amount of material off, and I mean only a TINY bit. The clutch is broken in at about 700 miles now, and works very well, and yeah, the misfire starts when I go into full boost, but only in the upper gears like 3, 4, and 5. And it's only on the driver side, like where the cam sensor is. Makes me think cam sensor or crank, or timing tensioner. I dunno.
I thought of that as well, but everything seems to be in order after tracing the wires... never could find a problem I might look at the injectors though, that's a good idea. The injectors are modded stockers, and relatively new, but I'll try swapping cyl #4 with another, and see if I get a different misfire code. I've traced the work the shop did as much as possible, but there's just not that much to unplug or remove/replace when doing a clutch install. I dunno. Thanks for the posts guys.
It's the cam sensor most likely. I'm willing to bet that the flywheel and clutch assembly isn't balanced well. My clutch sponsor took my flywheel and clutch kit and balanced them together.
Turned out the shop hit the turbine wheel (the d/p was removed for room) during the re-install of the clutch/flywheel. The impact broke a piece off the wheel and when I checked, there was some serious shaft play. I couldn't get anyone to fess up about the damage, but the shop did knock the price down a bit, which tells me they probably knew something.. In any case, at upper rpms the wheel/shaft assembly was "walking" and hitting the housing which explains the loss of power and the CELs (I would lose boost when the wheel hit, but still have the excess fuel which was choking the spark and causing the misfire). I replaced the turbo and haven't had a problem since. Just an update.