Cadillac Seville / Cadillac Eldorado Forum Discussion, Lean 4100 in Past Cadillac Vehicle Discussion; Searching "4100 lean", I came across this forum, and you guys seem to be very knowledgeable, maybe you can help ...
Searching "4100 lean", I came across this forum, and you guys seem to be very knowledgeable, maybe you can help me; my '85 Eldo has no codes, starts,idles and runs pretty well but behaves lean (intermittent needs additional pedal to keep smooth acceleration)after open loop. Already changed O2 sensor, readings jump b/t .2 and .8 at steady rpm (normal?), econ light shows balanced off/on in diagnostic (indicates proper mixture?), but i know the new reformulated gasoline has necessitated richer mixtures in my other old cars. I'm tempted to alter the o2 reading w/resistors to richen things up. unless someone here knows a better way?
Automobile(s): 1988 Allante' (sold), 1984 Eldorado, 84 Sedan DeVille
Re: Lean 4100
What's the fuel pressure? I think you have either a weak pump or the filter (sock) on the in tank pump is plugged up. This car runs with low pressure so if its below minimum it will be too lean. Your Oxy sensor seems to be working normally.