[s-cars] Missing once more

[matt ludwig]

Man Uncle Bob,

could it be what seems like a more commonly appearing problem for 
several listers- fuel flow/pressure? I know Cody is trying to track 
this down as well (to some extent) and obviously Hap solved the problem 
by invoking the Fuel Gods to descend upon the green machine w/ a 
totally new designed fuel system, but could your miss be caused by an 
intermittent, or fail(ing) Fuel Pressure Regulator? Seems like a 
candidate given you are seeing this @ high boost and thus high A/F 
delivery times.

just a stab though....

sincerely,

matt ludwig.
1995.5 S6 Avant

On Jun 28, 2005, at 10:42 AM, Robert Myers wrote:

>
> Hi Y'all,
>
> This is driving me nuts.  Yeah, I know - short trip.  :-(
>
> Miss Piggy (RS2ed '95 urS6) has developed another miss.  I have 
> experienced several failed PSOs and coils.  This miss appears to be 
> neither.  It feels almost like some sort of a flutter.  The change in 
> (Stromung) exhaust note is significant.  
> "Brap-rap-rap-rap-rap-rap-rap...".  The "miss" shows up only when 
> boost levels exceed 18 psig.  The engine runs perfectly until boost 
> hits 18 psig.
>
> This morning I ran a couple of errands and on the first jaunt the miss 
> somehow seemed to heal itself without any apparent cause.  (I hate it 
> when that happens.)  After shutting the engine down and taking care of 
> some brief business I fired Miss Piggy up again and the miss is back.  
> So much for the miracle cure.  :-(
>
> "Repairs" done:
> 1.	replaced plugs and boots (it was about time for that anyway).
>
>
> Diagnostics performed:
> 1.	attempted to localize miss to one cylinder - failed.  There seems 
> to be no difference between coils and behavior when injectors are 
> disabled one at a time.
> 2.	spark intensities appear to be consistent from one cylinder to 
> another.
> 3.	swapped in a known good ECU - no change.
> 4.	swapped in newly burnt chips - no change (either expected or 
> observed).
> 5.	Swapped BPV with another BPV.  No change.
>
> Suggestions anyone?
>
> Bob
>
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