Mechanics

RUNNING RICH WHY?

1996 Toyota Camry

Engine Performance problem
1996 Toyota Camry 6 cyl Front Wheel Drive Automatic

Toyota Camry 1996 (sept) 1MZ-FE engine.
I'm in Mexico, bought a well repaired Calif. Write off, probably has 200,000 Km. Two years ago.

6 months now, smokes on startup(blue, oil?) Once every 30 times, when cold, it failed emissions test (hydrocarbons, only barely above the limit).

Seems to me, running rich. Lots of black soot on the exhaust pipe, hesitates, backfires when taking off from a start.

NO check engine light, NO error codes. Has me wondering how is this possible? Bad cat converter, something after the O2 sensor?

New oil & filter, plugs 3000 miles old, air filter year old.

How can this be so bad, without check engine light?
Avatar
Paul Millette
July 21, 2010.



Probable causes of an engine running rich are as follows: 1. Excessive fuel pressure can be cause by restricted fuel return line or defective fuel pressure regulator.
2. Defective Oxygen Sensors.
3. Leaking injectors and fuel pressure regulator.
4. Coolant temperature sensor out of calibration.
5. Restricted air intake system.

Rasmataz
Jul 21, 2010.