Bad Cylinder... Need advice!!!

[Johnny]

Thor Johnson wrote:
> 
> Well, We were testing the FSAE car yesterday, and the car suddenly began
> to run rough.  Originally we thought it was because of lack of ECT
> compensation ("I'll get around to it..."), but it wouldnt run better
> today, so we did a diagnostic (limited) battery, and here are the results:
> 
>   I have been running the engine a *little* lean. 0.9v Oxy sensor is a
> tad lean for M85/Meth (no deposits of any kind, but no glaze or white
> electrodes).  We are currently running in batch mode (will switch to
> sequential Monday), figuring pulse time based on MAP+deltaThrottle.
> 
>   Cylinder #1 does not ignite (Oxy sensor, exhaust tube cold)
>    Has spark (checked externally, holding it to side of engine
>     Spark is shared with Cyl #4, operating OK.
>    Has fuel (will come out wet if you run the engine for a while)
> 
>   All other cylinders operate OK (.9V after 1/2 minute of running, @3 a
>    little leaner than most).
> 
>   No oil in exhaust (I think.   We get a white plume @ high R's, but I
> think that's the meth talking.
> 
> Any tests we can run to help narrow the problem?  Any way to fix them
> (easiest is best...Want all four working by Monday).  I think it could be
> due to the following, but have no idea how to check/fix:
> 
>   1. Sticky valve
>   2. Scratched cylinder (we just put an air filter on today!)
>   3. Blown gasket (though I don't see oil in exhaust...)

Not firing but has fuel and spark means you either get spark at the
wrong time, or you have a LARGE LEAK. Do a leak down on it. Takes about
a minute to do. Listen closely to figure out where it is leaking. You
will hear that "shhhhh" sound either in the crankcase, intake manifold,
or exhaust, or sometimes right out the side if it is a head gasket. If
you hear it in the crankcase, that usually means hole in piston, broken
ring land and ring, cracked piston, etc. If it's coming out the exhaust,
you have a burnt, bent, cracked, broken, or stuck exhaust valve. Ditto
on the intake valve if you hear it at the intake manifold.

Be key here is "white plume". Does it smell like hot oil? My first guess
is broken piston. Leak down will tell all. And yes, you can have a hole
or cracked piston with no other signs of anything wrong except missing
on one and white smoke at sustained high rpm. Been there, done that,
more than once.

good luck

-j-