Texas5.0

I also got that scanner and ran some codes and got 41 and 91. So ifI am reading the above posts the right way my O2 sensors are gone?

Codes: 11 -10 - 41 - 91.

Joel5.0

It depends (wise answer anh?...lol).....codes 41 & 91 as memory codes would need to be confirmed as "real" codes....they may have been logged under conditions that may not be present now. Suggest to run a KOER self-test, making sure you bring engine temp to op conditions (170° F +), and check if they show up as KOER codes (the system will increase A/F and force a rich condition + it will force a lean condition, and check if they switch). If codes 41 & 91 show up, need to make sure the HEGO ground wire is attached to the back of the driver's side cylinder head (tagged #19 in the diagram below)....if it's OK........the O2's are most likely 10-7.

Luckythirteen

Ok I switched my O2 sensors and now I have a 91 & a 41 code coming up, wtf did my other O2 die in transition?

Texas5.0

I really appreciate the help. I will run the KOER tomorrow after work and will see what happens.

Luckythirteen

Probably a stupid question, but is a KOER self test different from just hooking the scanner to the car while its off? If so how do you do a KOER test? And thanks for all the great info!

Joel5.0

If you're using a scanner, it should be either in the menu on the screen, or in the instructions......you basically turn on the engine first, take it to op temp, raise engine speed to 2000 rpms for 1-2 minutes (get those O2's and engine up to temp)...shut down engine, set up the scanner do do a KOEO, but start the engine instead of leaving it off.....you should hear the engine raise its idle, a code 4 flashed (4=8 cylinders engine), and start a sequence of real-time tests (1-3 minutes), engine speed will drop to idle, and any failure codes will start flashing.....they will be repeated in sequence (ie. 31-42-31-42) or code 11 (= Sys. Pass) twice.

Texas5.0

Ran the KOER and the same codes came out. 41 and 91. I guess it will be to the store for new O2 sensors. Yesterday I cleared the codes out and the check engine light went off. Has not been back on since. When I ran the test with the engine running good old 41 and 91 reared their heads again but still no check light.

Joel everything you said up top was good except for the engine code. the first number it gives is for the number of cylinders if it shows a 4 you have a 4 cylinder car. It should read 8 for 8.

Joel5.0

That's a "translation" problem.......[sm=trust_me.gif]...I know those like the back of my hand....[sm=smiley2.gif].....lol.....no.....a code 2 = 4 cyl. , code 3 = 6 cyl and 4 = 8.....unless the scanner does the multiplication by 2 on its own. Anyway....you do have a lean condition that will be logged as a memory code eventually. KOER does the real-time testing for you to confirm. You have to make sure you don't have a problem with the HEGO ground wire (not having a good ground there will cause lean codes), vacuum leaks, the presence of an open breather with a functional PCV valve in your setup, or snafu'ed O2 sensors.

Texas5.0

I forgot to look for that wire yesterday, I will do it today. I guess I need to check all that other stuff also to narrow down what is happening. I am confident I do not have vacuum leaks since I just changed all the hoses. I will check the PCV and then see what happens.

JZTRK

I have a 90 lx and the only code I get is a 91 and your seperation codes 10,11 I cant get it to give a 41 and the #19 wire is ok