Long cranking/Oh my aching ring gear

[Gregg Temkin <twincam@halcyon.com>]

I would appreciate any suggestions as to what to look for on my '89 
200TQW w/single knock sensor MC engine, to trouble-shoot a long cranking 
before start malady.  Usually the cranking lasts for about 5 to 7 seconds 
which is a hell of a long time for a starter motor to be working.  
Temperature seems to make very little difference however the engine will 
start fairly quickly if restarted within about 5 minutes of shuting down.

I've gone through, found and replaced a bad throttle position sensor, a 
bad single terminal thermal sensor and a bad 4 terminal sensor (replaced 
with a 3 terminal replacement) all without any effect on starting or 
performance.  (What do all these parts do in the first place if replacing 
them has seemingly no effect?).

I've done some pressure checks on the fuel injection system and except 
for one borderline low reading there appeared nothing wrong.  Leakdown 
was not a problem in my testing.

I've done nothing ignition wise other than replace the plugs and wires, 
which did cure a miss under load.

I noticed that the titles of several of Audi's Technical Service 
Bulletins mention long cranking times so I'm hoping this is a common 
ailment.  I have the Tech Bulletins on back-order but I fear for my ring 
gear in the mean time.

Thanks,

Gregg Temkin
twincam@halcyon.com