More on 1995 A6Q ignition switches and (lack of) fuel delivery

[Kneale Brownson]

Not familiar with the newer cars (funny to call a 10-year-old model newer),
but the circumstance you describe sounds like a cold-start valve failure if
there is a cold-start valve or function on the V6s.  

BTW, I think Audis since about 1990 require engine turning to trigger the
fuel pump operation.  Pretty sure that's the case on our V8s and 200q20v.


At 03:18 PM 11/13/2005 -0500, Grant wrote:
>As some of you may recall, I've been chasing a gremlin that has 
>resulted in 4 supposed ignition switch failures in a "b5" 1995 A6q 
>automatic (12V v6).  The first failure was the typical - the switch 
>would not return automatically to the "accessory" position, resulting 
>in a loss of interior power bits, until you manually turned the key 
>back.
>
>Replacement, now 18 months or so ago, resolved this problem, and it has 
>not recurred.  What has happened, is  that the car fails to start. It 
>cranks and cranks, but wont start.  This begins as intermittent and 
>becomes more consistent.  Voltmeter testing confirms that when it 
>starts, 13V is present at the fuel pump fuse, and when its not, 0V is 
>present.  If it cuts out mid-start, the voltage drops to zero.  So its 
>not the pump.  Note that the pump is not energized in the accessory 
>position, whcih surprises me. In all my other audi's (past and present) 
>it was - e.g.: turn the switch to accessory and the pump runs audibly.  
>Also note that a few times it started and idled ok, but quit when 
>shifted into reverse.
>
>The switch has been replaced twice to fix this. Both times the 
>replacement worked for anywhere from 2-6 months, then recurred.
>
>This time I took it apart myself (thanks to Bob Myers for instructions. 
>BTW, even more extensive instructions are available on AudiWorld, or as 
>PDF from me now).  It seemed that if I disturbed the harness, it could 
>fix the problem. So I disassembled everything, inspected the harness 
>(found nothing obviously broken), cleaned all the contacts (cramolin), 
>and put it back together.
>
>Now it starts consistently, but will stall out if it has not run 
>recently. Oddly, given my note above, if you leave the switch in 
>accessory for a few seconds and then start it, it runs fine and will 
>not quit/stall.
>
>So - does anyone have words of wisdom?
>- might a fuel filter be clogged?
>- should the pump energize in accessory?
>- any other advice?
>
>Grant
>
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