Quote:
Originally Posted by truckin 79
Well I think my truck is messing with me. When I adjust idle mixture screws and reach that magic number of 14.7/1 to 15/1, then drive it around it goes rich on me to around 13.5/1 when I come back from a drive. I try to lean it out and almost seems like it gets richer on drives.
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A couple things to be aware of here. Fuel temperature makes a big difference. Manifold temperature makes a difference, but not as much. You also have to consider under hood temps. The hotter it is, the richer it will be. That might be why it is good when sitting idle, then rich after a drive.
Be aware of your power piston. Make sure it is bottomed out at idle in drive. You can take a small rod down the vent hole and feel the power piston. Try this with the engine off so you can feel it push down against the spring. Start it up, put it in drive, and see if it is pulled all the way down, or if you can push it down further. I'm wondering if leaning it out has it running at lower vacuum, opening the power piston sooner.
Don't forget to set your ignition timing.