[V8] Help Diagnosing V8 Problem...

[Alan Kramer]

Steve,

    The O2 sensor going lean does not mean conclusively that it can't be 
spark.  What it means is that at least one cylinder is not firing, so there 
is "unburnt" O2 passing through the cylinder and into the exhaust system 
which is measured by the O2 sensor.  It could be either a no fuel or no 
spark situation.

    I'm not sure if the output tests will tell us anything because the car 
always starts and idles fine, so doing the output test while the car is off 
probably won't be conclusive.  I'd expect it to pass.

    If it were fuel rejectors, we'd think we should expect codes 4411-4 
along with a signal to negative or signal to positive condition showing up 
on vagcom... we get nothing.

    I guess one possibility that I just thought of right now is an 
intermittent open circuit to a pair (or multiple pairs) of cylinders.   
Perhaps the engine is rocking just enough when it comes under load to cause 
a disconnect somewhere...?   I wonder if an open on those wires will show up 
as a code?

Thanks for stirring up the thought process...
Alan



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Alan Kramer
http://www.geocities.com/audikramer

'83 CGT 20vt
'86 4kcsq
'90 V8q
'83 UrQ #519 (recipient)
'91 V8q (engine donor)

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