1996 Toyota Camry running rich Why?

1996 TOYOTA CAMRY
Avatar
PAUL MILLETTE
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?
Jul 21, 2010 at 11:43 PM
Advertisement
Avatar
RASMATAZ
  • ASE Certified Mechanic
  • 75,992 POSTS
  • ASE Certified Mechanic
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.
Jul 21, 2010 at 11:45 PM
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.