Clanking from the Right Bank of Cylinders

LetItSnow · #1 08-25-2009, 03:30 PM

CN: My engine is clanking, seemingly from the passenger side.

The story so far:
August 1: First day of a <two-day autocross event>. As usual, the car was full steam ahead.
August 2: My buddy hops in for five runs, and I follow suit. During the fifth one, the engine hesitates, and a few seconds later it stalls. I coast off the track.

The engine turns over, but the idle is terrible. I do some experimentation with pulling individual injector wires to try to track down the problem. It seems that the driver's side cylinders aren't cooperating, as pulling their injector wires doesn't change the idle, where pulling the passenger side ones kills the engine.

After messing around in the engine compartment, giving it another try, the engine fires up, idling as smooth as usual. I drive it halfway to the paddock, where it cuts out again. I end up towing it home.

Doing some coil testing, I pull the driver's front coil, put a plug in, place the plug on the block, and have the wife crank the engine. Spark, spark.

Check Engine Light rears its ugly head. Cam Position Sensor is the problem, it says. For sport, I replace it; my oscilloscope test of it is posted elsewhere. The original was definitely a dud. After installing the new one, the engine idles just fine and revs freely. And there is much rejoicing.

The test drive halts the rejoicing. The beginning was good, but after about ten miles, there was an occasional buck, like hitting fuel cut. It started to happen at higher RPM with a good share of throttle, and eventually became more frequent at engine speeds as low as ~3500, and half the time it felt like the car was down on power. I managed to get the car home.

In the last two blocks, I noticed a rather loud, speed-dependent noise that wasn't there before. Now, the engine has a nasty clank which seems to be coming from inside the passenger side of the engine. At one start, the clank wasn't there and the idle was fine, but it started to clank here and there, and then more regularly in spurts, and then regularly. Now, it does it all the time.

A buddy is recommending draining the oil to see if there's any evidence of bearings haven gone bad, and considering sending a sample to Blackstone Labs.

I'm fearing the worst, but there's a good share that I don't know about the 3.3 that our gurus do, so fee free to pitch in?

TomsSVX · #2 08-25-2009, 05:20 PM

Was the sensor replaced with a used one? The bucking I have experienced w/o a DTC because the sensor was bad

Tom

LetItSnow · #3 08-25-2009, 05:36 PM

The replacement sensor was brand new.

TomsSVX · #4 08-25-2009, 05:37 PM

hmmm. Check the timing belt to make sure it has not jumped

Tom

want-a-fast-svx · #5 08-26-2009, 12:36 PM

Just a thought but when the crank bearings went on mine totally it clanked and sounded horrible. You could see and feel the play in the crank on mine. The crank walk was absurd. Just a thought see if you crank pulley has any play?

LetItSnow · #6 08-30-2009, 08:22 AM

I'm finally getting time to check this stuff out; I'll let you know.

Meantime, if you can get a better idea from the sound itself, it's just like this:

Crazy_pilot · #7 08-30-2009, 10:35 AM

Sorry Rob, but I don't think there is a good ending to this. Definitely drain the oil and look for bits of rod bearing. I'm amazed that it went so fast though, my car may be on the same path (I get a nasty rattle when it fires up that settles within a second), but in 8 months or so it hasn't gotten noticeably worse. What oil do you run for Auto-X?

TomsSVX · #8 08-30-2009, 10:43 AM

Agreed,doesn't sound like an easy fix

Tom

want-a-fast-svx · #9 08-30-2009, 01:29 PM

Ewwww....sounds eerily familiar sorry to say. Only thing that would be easier fix but i havent heard it since im an manual is maybe the flexplate. I dont think they typically make that much noise and it certainly sounds like when the crank bearings went out on mine but it s a thought.

LetItSnow · #10 08-30-2009, 01:55 PM

Who's got a flexplate?

My car hasn't had one of those for a couple of years now.

The local yard is advertising an SVX engine for $750...

Crazy_pilot · #11 08-30-2009, 02:17 PM

You car is a summer-only car now right? I say N/A build over the winter.

want-a-fast-svx · #12 08-30-2009, 05:23 PM

oh well than yup time for an engine!

LetItSnow · #13 09-02-2009, 10:17 AM

I've got a 70k mile engine en route. Any suggestions on what I should do before it goes in? (That doesn't mean high compression pistons or forced induction!

)

subiemech85 · #14 09-02-2009, 10:38 AM

sparkplugs

1986nate · #15 09-02-2009, 12:01 PM

full reseal