[Supras] Very rich start with code

[Hacker J]

Is it just me, or is everything in the digest being duplicated???

Anyway, after a cold start the ECU is running open loop until the coolant sensor reaches operating temperature. As a result, your O2 sensor code is a symptom of some other problem that is causing the car to run very rich. Rarely does an O2 sensor need replacing (they are probably the most unnecessarily replaced part in the entire emission system), and its especially outrageous because they can readily checked before replacing with only a propane torch and a multimeter.

If the rich condition is only on a cold start I would focus my attention on the cold-start injector circuit. The CSI is powered only by the starter circuit, so it should shut off immediately after cranking. If it is not I would suspect a sticky CSI injector and less likely a bad switch. It is also possible that one of the main injectors is sticky when cold and flooding the manifold.

Best thing to try would be to disable the CSI by disconnecting the CSI switch and trying a cold start. If its cold outside, it will likely be hard to start but once running should not put out any black smoke.

Jon
90T


----- Original Message ----


My 92T does exactly the same thing....i drive it about 1 or 2 days a
 week to work.
The code was related to 02 sensor signal.  It doesn't bother me too
 much since the light goes off after a few minutes of driving.
If the 02 sensor wasn't so dang expensive, i'd have replaced it
 already.Darren92T 5-Speed White PackageCanadian Model in Florida>
 ------------------------------
> > Message: 

> Mine started right up this morning after sitting
 for a couple of days but I admit it usually takes a couple of
 attempts. > I've noticed lately that it starts really rich as in lots of black
 smoke and the check engine comes on for about 3 minutes then goes off
 again. The code when I checked was related to the O2 sensor. > Is it
 more likely that the O2 sensor is nearing the end of its useful life or an
 overly rich or stuck open start injector? I'm getting ready to install
 the MAFT in speed density mode and would like to belive I have
 everything in order before making that change in setup.> > Thanks,> Rockey 91T
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