Hi folks,

I've searched the archives and can't seem to find any information on the problem I'm having w/ checking the mixture using a dwell meter.

I've found the port on the driver's side rear engine and when I plug in the dwell meter to the port, the meter immediately goes to about 10-12 degrees on the 4 cylinder port and stays there, vibrating between 10-12.

I've had it connected in cold start, warm start, o2 sensor connected, o2 sensor disconnected and I get the same result.

I've checked the O2 sensor and it's fine as well.

I've also tried adjusting the A/F adjustment screw and I can tune it fine using the screw, I'm just not getting any change in the output of the test port.

At this point, I want to make sure that my Lambda system is working properly.

Thanks!

Mike
86 930

 

I am having trouble determining what is exactly wrong with mine also but when you disconnect the O2 sensor you should get a stable reading on the dwell meter. With the O2 sensor plugged in, it should fluctuate around where the needle was stable. If you open the oil cap (vacuum leak) the dwell should increase. My Chinese made dwell meter reads incorrectly so sharing my numbers with you won't help.

What voltage do you read from the wire that connects to the O2 sensor from the computer when it is disconnected?

I am not familiar with any CIS differences between an '81 SC and a '86 930.

 

I think maybe the Dwell meter is malfunctioning (chinese as well).. the O2 sensor reads between .75-.80 because I've got it dialed in a bit rich for a better cold idle.