Could be a dumb question? :P

[element913]

Hey guys,

Ive run a few datalogs, and imported them into the EEC analyzer software. I have noticed that my LAMSE1 and LAMBSE2 values tend to go into the lean range occasionally (and the rich range, sorta back and forth). Not terribly lean or rich (16 is about max on lean side, and 12 is about max on rich side). However, the average of the readings is about dead on with what it should be ~14.7. Is this ok? Should it NEVER read lean? It tends to get lean for a ms (or whatever the time interval is) or so around the time the secondaries open up.

Im new to this stuff, and I just want to make sure its not bad for the motor.

Also, can I take the readings in the LAMSE as accurate? Or should I start saving for a wideband (~$500).

Thanks,
Mike

 

[Axianator]

LAMBSE values only represent the commanded A/F ratio for that particular moment. That means that if closed loop operation has been scheduled and a HEGO sensor for a particular bank is indicating a lean mixture, the EEC will command a richer LABMSE value for that bank until the mixture is brought back to more a stoich reading of 14.64:1. Similarly, if a HEGO sensor indicates a lean mixture and closed loop operation is again being utilized, the EEC will command a richer LAMBSE value until the mixture for that bank is brought back to the desired stoich reading. The one thing to remember about this process is that the EEC will never settle on 14.64:1 and stay there - to do so would mean little to no variance in HEGO readings (due to a lack of sensor switching) which would indicate a bad HEGO sensor to the EEC. This "never being satisified with a stoich reading" strategy (combined with the factory adaptive programming) is why you will often see LAMBSE values that are leaner or richer than the actual desired A/F reading.

Another thing to keep in mind regarding the factory HEGO sensors is that they are little more than "switches" which are only capable of indicating (within a narrow range) how far off the mixture is from the desired stoichometric mixture of 14.64:1. For this reason, one should never rely solely upon factory HEGO readings or LAMBSE values when performing any in-depth fuel delivery tuning. Readings should instead come from a dedicated, reliable wideband HEGO sensor setup (like a PLX or AEM series wideband setup with dedicated controller and data output port) that is capable of sensing and relaying the proper readings within the A/F range that you will be tuning in.