924Board.org

[Roger Hall]

My 81 924 seems to be running lean. I read the Haynes manual and it describes how to adjust the fuel mixture. I know that you need a gas analyzer according to the book but I just wanted to richen the mixture a little to see if it helps. Shop has checked the mixture I am just running out of things to try.

[numbers]

A lean condition in these cars is usually caused by a vacuum leak, not a mixture problem. Adjusting the mixture just masks the real problem. If you want to verify the lean condition, take your car in for a smog check. If you are running lean, you NOX will probably be high. If you are running rich, your hydrocarbons will be high. You can also buy a mixture guage that works off of your O2 sensor for about $15.00.

[Roger Hall]

I replaced most of the vacum lines, and one of the boots. I have not tested the system though. I will take your advise a vacum test is simple and cheap. In the manual it says that there should be a rubber plug over the mixture adjustment opening. Could there be a vacum leak from the mixture adjustment opening? Guess I will find out.

[-nick]

the rubber plug isn't supposed to be air-tight. it just keeps debris out. if you do adjust the mix keep in mind that a very small twist on the adjusting screw changes the mix considerably. an 1/8 of a turn one way or the other is usually all that is needed.

btw- those air/fuel mixture gauges aren't really precise enough to tune by.

regards,
-nick

[Joes924]

I welded the oxy sensor closed last summer when I replaced everthing behind that with straight 3"pipe and a glasspak with the resonator welded tothe end ... I was looken at some site the other day and saw a oxy sensor kit with the attachment to the same thing on the pipe and it was a naet little unit..I think 2 lights one red the other green 1 being rich the other being lean when they both lit up you were dialed in for
$ 150..0 I think i wouldnt mind haven one .