Re: O2 Sensor Diagnostics

[PDQSHIP@aol.com]

In a message dated 96-09-02 09:42:32 EDT, you write:

<< 	Also, what kind of meter are you using?  It is possible that a
 digital meter might be aliasing, giving weird readings.  (Is that the
 term, digital gurus?)  Also, the meter must have a very high impedance so 
 as not to draw any significant current, or this will screw up the 
 signal that gets sent to the engine while you are reading it.
 
 > My question: Is the O2 sensor toast and the ECU is changing the air/fuel
mixture
 > as told to, or is it something in the ECU and the O2 sensor is just
providing
 > feedback to what is actually going on?
 
 	If the O2 sensor is wrong, the ECU will be deceived, and the final
 mixture will also be wrong, which will cause all sorts of drivability
 problems. 
  >>
A better test, paul, is to grab the diagnostic plug (2 prongs green/purple
and brown) up near the fuel filter....  That gives you the duty cycle of the
O2 Freq Valve......  You can use a DC meter or a dwell meter (90% X DC =
Dwell angle on 4cyl engine), the factory spec is 50+/-8 DC, you want to set
at 42DC or 38dwell.....  A warn O2 will show great fluctuations in reading, a
new one is more steady for a given reading....  To adj, a 3mm t-handle hex in
the port between the FI boot and the fuel dist lines....   A turbo car will
eat an O2 faster than a N/A car, and a bad fuel mixture can eat the O2 as
well....  60k is pushing it, me I can tell when mine goes south, cuz the gas
mileage takes a 5mpg plunge, usually 30k or so....

HTH

Scott