Engine Light keeps coming on Cavalier 1.8 8V

[Windy]

A friend of mine has a problem that has me stumped any help would be appreciated

1.8 8v Cavalier with single point injection.

Engine light comes on at regular intervals any thing from 30-80 MPH in any gear. The only codes registered are for a weak mixture.

I have blanked off the vacumm powered EGR valve as it was leaking, run injector cleaner through the system (From looking into the throttle body spray pattern looks ok). Changed MAP sesor and looked over engine looking for loose/damaged hoses etc. Checked plugs/leads etc cannot find any reason for the mixture to keep going lean/weak. Any one had this problem or have any other ideas

 

[malcolm]

A friend of mine has a problem that has me stumped any help would be appreciated

1.8 8v Cavalier with single point injection.

Engine light comes on at regular intervals any thing from 30-80 MPH in any gear. The only codes registered are for a weak mixture.

I have blanked off the vacumm powered EGR valve as it was leaking, run injector cleaner through the system (From looking into the throttle body spray pattern looks ok). Changed MAP sesor and looked over engine looking for loose/damaged hoses etc. Checked plugs/leads etc cannot find any reason for the mixture to keep going lean/weak. Any one had this problem or have any other ideas

How many crosscounts are there on the oxygen sensor?

 

[Windy]

Only going on blink codes no access to Tech 1 or 2 to check O2 sensor. No surging on light throttle etc or codes to show duff sensor.

 

[malcolm]

Only going on blink codes no access to Tech 1 or 2 to check O2 sensor. No surging on light throttle etc or codes to show duff sensor.

You can measure the crosscounts with a standard dvom.
login as a guest at the following site for instructions:
http://forums.delphiforums.com/cartune/messages?msg=38.1

Exactly what fault code are you getting?

 

[Windy]

Error code 44 (lambda sensor too weak)

I will test o2 sensor as per link. I have a Fluke Scope meter which I can hook up

Steve

 

[malcolm]

Error code 44 (lambda sensor too weak)

I will test o2 sensor as per link. I have a Fluke Scope meter which I can hook up

Steve
MPH

The fluke meter is more than adequate. Code 44 has three possibilties. O2 sensor / wiring / ECM. If the sensor passes the crosscount test, measure the signal at the ECM. If the signal is present, suspect the worst. If it is the ECM, you should be able to get a secondhand one without too much trouble.