[s-cars] No Start ABY/AAN engine - Problem Found?

[Huw Powell]

On 10/2/2010 8:17 PM, Joshua Van Tol wrote:
> They do bounce around quite a bit. +/- 10 degrees was overstating it a
> bit, but +/- 2 degrees isn't uncommon.

I'll buy that.  And I also understand that on these turbo engines Audi 
wanted really precise control of ignition so they could push the advance 
safely.

My old F250 used to jump all over the place, by the way.  Timing was 
more like "well, it's sort of close, and it runs" rather than "6 degrees 
BTDC".

> On Sat, Oct 2, 2010 at 6:22 PM, Huw Powell <audi at humanspeakers.com
> <mailto:audi at humanspeakers.com>> wrote:
>
>
>
>
>      > Second, you do not want the pins on the cam. The timing belt has slop
>      > and the valve springs cause the cam to bounce back and forth in this
>      > slop. This will cause an ignition timing variance. Because it's on
>      > the cam that variance will be doubled. You do not want your ignition
>      > timing bouncing around +\- 10 degrees ;-).
>
>     So how come cam-driven distributor spark control systems don't seem to
>     do that?
>
>     Not saying they are rock-solid, but they sure don't bounce around
>     that much.
>
>     --
>     Huw Powell
>
>     http://www.humanspeakers.com/audi
>
>     http://www.humanthoughts.org/
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>

-- 
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/