Re: ECU/Oxygen sensor question

["David G" <daveglu@hotmail.com>]

As far as testing goes a leaking or cloged injector will usually cause a
rough idle, sometimes when injectors are flowing at different rates the
computor compensates for the rich ones by shortening the pulse width causing
the lean ones to be worse.  If you have a rough idle then they can be tested
by pulling a plug wire to determine which cyl is missing.
  However if your car has many miles and/or you suspect it needs injectors
(non-cis) they can be cleaned very reasonably ~$15ea, a local shop here does
it for that and gives you a print out with flow rates and spray patterns
before and after cleaning.
  Dave G
http://www.pelkie.com/mycars.htm

>Would an exhaust gas anylizer show anything?
Not normally
> Has anyone had their injectors cleaned/inspected as routine maintenace
> and how much did it cost?
Yes (non-audi) -  see above
>
> Still troubleshooting this:
>
> 1991 Audi 90 Quattro 20 Valve
>
> I have been experiencing surging under light load in 2nd or 3rd gear
> under
> light throttle.  While cruising it feels like the engine is cutting out
> momentarily, kind of like when the AC is on (which it isn't).  I
> replaced
> the oxygen sensor and now I no longer have a hunting idle after coming
> to a
> stop but the surging is still there.  The idle also isn't as smooth as
> it
> was a couple weeks ago.  I searched for vacuum leaks with propane and
> found
> nothing.  Techron didn't work.  Plugs are new.
>
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