

| Subject: | Fuel Injection Adjustment/ High CO at idle |
| From: | Mark Keller |
| Date: | Sat, 28 Apr 2001 07:50:21 -0800 |
Hi Steve, Congratulations on taking this project, It gave me great satisfaction to learn exactly how my system worked. I'd be interested in the correlation between the CO meter and the O2 output voltage when you get a chance to compare them. As to your questions, I wrote quite a bit about the fuel injection system when I was on the project. Look under my name, Mark Keller, at www.gerry.vanagon.com, in the last two years. As to the High CO at idle, I believe the best thing is to realize that the Fuel control system is dependent on fuel pressure as a preprogrammed value; so if your injection system is higher or lower fuel pressure value because of: timing, vacuum leaks, worn parts, etc., then the system has a built in error in the fuel injection map. I say this because I originally didn't know this. I believe that verifying the Fuel injection pressure regulator and such is the first step. Since hypothetically anything that contributes to a low vacuum signal to the fuel pressure regulator could cause the fuel pressure to be higher that the pre-programmed values. Having said that, The Fuel injection voltage signal from the AFM can be tweaked by repositioning the wiper arm. In fact a good wiper arm/ carbon track maintenance is a excellent second step in your project. The job is straight forward, but loctited screws complicate it. Oblong the holes in the circuit board to relocate the wiper arm contact to a new position, clean with a electronics type spray. Spring tension is the next step. I don't know the exact Pro Training Manual Values, these are approximate. Disconnect the O2 sensor and monitor its voltage while driving at a steady 3000 RpM, driving conditions, read the voltage on a multimeter and aim for a spring tension that gives you around .7 volts. Then you can go to working on Idle adjustments. Sincerely, Mark Keller 91 Carat Cowichan Bay, BC
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