UPDATE #2 Re: Misfire on cyl. 2

Huw Powell audi at humanspeakers.com
Tue Jul 5 23:30:04 EDT 2005

> Ok, after some experience driving this weekend, the car (1991 100, 2.3l 
> NF engine) is still running very poorly.  Significant loss of power 
> (lose ~5mph going up hills on the freeway, can't accelerate) and fuel 
> economy (~12 MPG!), and rough running - seems like cylinder #2 isn't 
> firing, unplugging its spark plug wire doesn't change the idle.
> After about 300 miles since the new spark plugs were installed, I pulled 
> #2 to look at it again.  *Significant* oil fouling.
> Picture here: http://people.msoe.edu/~yoderw/stuff/oiled_plug_small.jpg
> (24kB, 640x480 JPG)

To me that just looks like a plug that isn't firing (yeah, as if I know 
what I'm talking about...).  What oil is there is coming from normal 
cylinder wall leftovers, not being burned by combustion cycle.  Looks 
more gasoliney to me, anyway.

> Another question (somewhat rhetorical, but...) is "why did this happen 
> all of a sudden when I changed the oil, plugs, and dist cap/rotor?"  I 
> checked the oil level after seeing the fouled plug, and it was a quart 
> too high!  Now, I know I only put in 5 quarts, because I only *had* 5 
> quarts... and there's only 5 empties in the garbage.  4.5 quarts came 
> out, just like normal.  I drained a quart out, and it looked/smelled 
> normal - no coolant or anything in it.

Unlikely to be an entire quart of gasoline run in there past the rings, 
but, hey, it's a hypothesis at least.

I know you swapped plug wires, and that you also checked injector 
pattern & flow (and all were equal, right?).

How about if something is preventing this cylinder from sparking?  Can't 
be the plug or wire - what if it's the dist cap, or perhaps some weird 
anomaly with the windows that trigger the Hall sender?

Here's a way to check (other than simply swapping in another dist cap).

Move all five spark wires one place CW or CCW on the dist, and then 
rotate the whole body 360/5 = 72 degrees to get it back to the right 
timing (you can only do this if your dist locking plate has been 
de-rivetted and removed).

Then see what happens.  Oh, clean that plug a bit befoe the test, of course.

Can we have a photo of the inside of your new dist cap?

Huw Powell



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