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Old 10-30-2009   #15
Paul Workman
 
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Join Date: Nov 2007
Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri
Posts: 6,466
Default Re: Another 1991 Fails CA emissions... Help!

Quote:
Originally Posted by gbrtng View Post
The audible pinging is a clue - it's running lean with advanced timing. Maybe a failing injector or knock sensor.
I agree w/ gbrtng that the pinging is the clue that it is running lean, and or the spark is too advanced(?), especially if it is pinging on 91 octane. Marc H can provide you with a chip that will bring the fans on while the temps are a little cooler. Cooler would help N0x, but too cool and HC will creep up - it is a balancing act. 10º cooler (both fans coming on at around 206-210) might do it for ya.

Anywayz...I would do a dynamic scan/data logging to see what other clues might pop up before I started changing this and that in hopes the problem goes away. BTDT.

P.

Last edited by Paul Workman; 10-30-2009 at 05:25 AM.
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