<VV> Idle problem - Again!

[Larry Forman]

At 07:46 PM 3/3/2005 -0500, Jim Houston wrote:
>Well, taking all of the suggestions, I have reset the valves, removed the 
>carbs and checked them again, checked the timing, etc.  The engine still 
>refuses to idle..  if I let the rpm drop below 1200, it just stalls out 
>and quits...  Anybody have any other ideas??   HELLLLPPPPPP!!!!!!
>
>Jim Houston
>Brandon, FL

Hi Jim,
While this is a long shot, it might be worth checking, just because.  If 
your crank shaft timing gear has slipped then all bets are off.  The 
fastest way to check it is fully explained in the Corsa Tech Guide and Bob 
Helt's book.  Drain the oil, and drop the oil pan, hand rotate the engine 
to the compression stroke on number 1 cylinder with engine TDC.  Crawl 
under car and check for "the mark" on the cam gear and see if it is lined 
up with the engine block case split right at the bottom of the gear.  You 
will need to view looking backward below the bell housing.

FWIW, my unknown history 140 pullout had a crank gear slipped between 3 and 
4 TEETH.  It is a wonder it even would run at all or didn't mash all the 
valves.  While most would not be that far off, having the valve timing off 
will definitely affect engine running.  This is a check for each time you 
are assembling an engine or for those particularly pesky mysterious engine 
problems.

You could also try advancing or retarding the engine when you are at 1200 
and then see if you can lower the engine idle.  If you are able to get it 
to run better when off of correct timing, then drop the pan.  Also check 
that the harmonic balancer marks are aligned.  If not, that would fool you 
into misadjusting the timing and affecting idle.

Does the timing stay rock solid?  Also, watch the dwell angle and see if it 
is staying constant.  Do you run points or Ignitor and if Ignitor, which model?

Finally, "When in doubt, swap it out!"  (I mean the ignition coil)  Simple, 
quick and relatively inexpensive to change.  If you have a stock ignition 
coil you are WAY overdue for replacing it.  Replace it regardless.  These 
can make the engine run funny in many ways.   Also check for a fat spark 
when holding a spark plug lead about 1/4 inch from ground.

Finally, and then some,  you can make your own cylinder balance checker by 
taking a WELL grounded clip lead and an opened paper clip and short 
successively each ignition wire at the distributor cap, having pulled back 
the rubber nipples before starting the engine.   The cylinders with no 
affect have the problem.  Best if you can lower the idle somewhat.  Yes, I 
remember, that IS your problem!

Let us know what you find.

-- Larry