Test for bad o2 sensor w/ tactrix cable?

Hi guys,

 

I've been getting some pretty crappy gas mileage, and would like to see if it's possible to use my tactrix cable to test the o2 sensor values.

 

Stats on my car:

 

2005 LGT, 5EAT, 36k miles

Getting around 17mpg mixed ( maybe 60% stop-and-go, 40% highway driving ).

 

The CEL hasn't been tripped, but I'm told sometimes the o2 can not work as it should without tripping it.

 

Is this something I can just log and look at voltage values?

I do not remember off the top of my head if you could log the actual V but I know you could log the front o2 afr..at cruise and idle it should be hovering around 14.7..

Use learning view and post the .csv.

 

Also, datalog AFR #1 and also the rear O2 sensor voltage during cruise

Thanks Mickey - I'm going to log these today and see how they look.

not to jack the thread, but i have the same problem. bought my car got between 20-22 mpg average. CEL came on and cruise is flashing. i know my O2 is done, and i have been averaging about 17 mpg. would love to see the result you come up with. might solve my problem

Ok guys,

 

Here are the logs and relevant information:

 

- The car is currently running MickeyD's open-source stage 1 tune, revision 3

- 93 octane gas ( 10% ethanol ) has been used

- The car is in DC at sea level basically

- Logs taken at around 50 degrees F

 

Originally when I ran logs on this tune, I saw no knock. However, learning view seems to be showing some corrections.

 

See attachments for AFR + rear O2 voltage. I can do some more 3rd gear pulls later.

 

File descriptions:

LearningView_11-23-2009 8 08 43 AM.csv - the learning view CSV

idle-romraiderlog_20091123_081218.csv - logging AFR+rear o2 right at car warmup / idle

cruise1-romraiderlog_20091123_081703.csv - logging AFR+rear o2 at cruise (low speed - 20mph or so)

 

... same for cruise2/cruise 3

 

* The cruises may not have been on perfectly flat ground so you might see a bit of acceleration/load.

LearningView_11-23-2009 8 08 43 AM.csv

idle-romraiderlog_20091123_081218.csv

cruise1-romraiderlog_20091123_081703.csv

cruise2-romraiderlog_20091123_081749.csv

cruise3-romraiderlog_20091123_081810.csv

Also,

 

Here is the RomRaider .hex file that my car is currently running:

 

http://www.dc4me.com/other/stage1-rev3.zip

Nothing really jumped out to me from your logs. o2 sensor looks to me like its working fine. We would more than likely see the afr value oscillate throughout cruise if it were bad. Logging ‘Engine Speed’ would be nice to see. Your fueling from your learning view is just a little off but nothing dangerous. Any chance you’re running an intake or an aftermarket air filter, ie (Walmart Brand, Fram, Non OEM) in the stock airbox?

Nothing really jumped out to me from your logs. o2 sensor looks to me like its working fine. We would more than likely see the afr value oscillate throughout cruise if it were bad. Logging ‘Engine Speed’ would be nice to see. Your fueling from your learning view is just a little off but nothing dangerous. Any chance you’re running an intake or an aftermarket air filter, ie (Walmart Brand, Fram, Non OEM) in the stock airbox?

 

The car is completely stock except for the tune. As far as I know, the air filter is the original OEM one.

 

However, I was planning on replacing it with a Fram Air Hog filter that I have sitting around because I don't think it's ever been changed.

Don't switch to even an aftermarket filter, as I've seen fuel trims affected fairly drastically by them on a couple of members cars. Because its cheap and easy you should try buying a new OEM filter and putting it in your airbox, then restart your ecu drive for a while and see if fuel trims are within reason... sorry for the delayed response.