A62.7TBend

awhile back, there was a discussion on setting the CO duty cycle to 42% for a 1.8bar car. today i whipped out the dwell meter and figured i would give this a try. I found the correct leads near the fuel filter to measure the duty cycle, but could not get a dwell reading.

My question is this. If the setting is too far out of whack, will the computer not give a duty cycle reading on this test lead? And if i play with the 3mm adjuster enough to bring it back near spec, will it start sending a signal to the test lead, or is the lead likely bad?

Thanks

tim200tq

I would think it's a dead wire. Try the colored wire and the ground at the bracket on the manifold where the ECU gets its ground. The Bently could probably tell you where to find the signal at the fuel frequency valve if the wire is dead. That is what the test signal is. If you hear the frequency valve cycling there should be a reading at the test connector.

If your car is running fine I would not adjust the mixture until you can be sure where you are going with it. If you're worried about going lean you can turn the 3mm clockwise 1/4 turn and see if it runs ok for a while. Are you sure that your meter is working and properly set up? Do you have access to another meter?

One last thought. Was the car fully warm? The adjustment should only be done when the system is running closed loop. Closed loop means that the OXS is giving rich/lean signals to the ECU which it adjusts for via the FFV.

Did anyone guess that I've been reading my Probst book lately?

A62.7TBend

I tried two meters, one was a cool snap on with integrated osciliscope. I will try to pick up the signal at the valve

tim200tq

How much for snap-on meter?

A62.7TBend

My friend said is was like 700