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You would need to look at fuel trim data and freeze data to see if it is a ‘lean at idle’ or a ‘lean under a load’ on a scan tool.
The obvious checks will be to check for vacuum leaks and checking for correct fuel pressure. I would also look at the MAF and see if the element is dirty.
Again, looking at your freeze frame data, it should be able to give you a good heads start.
Quoted From dreamer2355:
You would need to look at fuel trim data and freeze data to see if it is a ‘lean at idle’ or a ‘lean under a load’ on a scan tool.
The obvious checks will be to check for vacuum leaks and checking for correct fuel pressure. I would also look at the MAF and see if the element is dirty.
Again, looking at your freeze frame data, it should be able to give you a good heads start.
Ya…its under load…one thing i am confused about is my scantool lists stft1, stft2, ltft1, and ltft2….not sure if that is each bank or what…ltft2 is pulling for tons of fuel….its at 23.0
Quoted From Beefy:
Why do you think it’s lean on that side? Do you have a CEL?
Cel is on….p0174 which is lean on bank 2
Is the truck running rough? Your scan tool is confusing me too. Normally, short term fuel trim and long term fuel trim are listed as one number, and the o2 sensors are listed separately.
Does your scan tool list them separately, as in show voltages for each? Or is that how it shows them (in fuel trim numbers)? I don’t know what tool you are using, but that’s wierd.
I am using otc scanpro elite 3499n. It doesnt show that for all cars i work on. It has voltage data for o2 sensors as well. I can graph them too. The truck is running a little rough…it hunts for idle a little.
Actually, in the first post of this thread by TexaxCoder, he posts a youtube video where he demonstrates using a shop vac on ‘blow’, not ‘suck’ (tee hee) and some soapy water to hunt for exhaust leaks. You have to go to the video from the link, as it is private otherwise I think, or I would’ve just linked the vid.
Quoted From Beefy:
Actually, in the first post of this thread by TexaxCoder, he posts a youtube video where he demonstrates using a shop vac on ‘blow’, not ‘suck’ (tee hee) and some soapy water to hunt for exhaust leaks. You have to go to the video from the link, as it is private otherwise I think, or I would’ve just linked the vid.
I forgot about that one. Thanks for sharing it again Beefy!
I would start with vacuum leaks if none found than a fuel pressure check. also check your egr valve. good luck and keep us posted. C8-)
You should have fuel trim numbers for both banks.
If the issue is under load according to your freeze frame data, you need to be looking at fuel pressure usually and still check for vacuum leaks particularly the lower intake manifold.
What are the STFT numbers at idle for bank 2? Are you able to graph your Bank 2 Sensor 1 o2 data? Lazy o2 sensors can also cause lean codes.
Did you check around the bank 2 exhaust manifolds for leaks?
Here is a good video on doing research on lean codes, granted this video shows 2 lean banks but you can follow the same diagnostic principles.
http://www.youtube.com/watch?v=nYN-RoFV … AAAAAAAEAA
Hope this helps.
I agree that it is a little strange they list fuel trim for every sensor. I would also suggest checking fuel pressure as well as for vacuum and exhaust leaks before condemning the sensor especially since you have an idle issue as well, BTW this leads me in the direction of a vacuum leak as they often behave that way.
Do you have access to a smoke machine?
There is also another way which is slightly dangerous. You can plug up the exhaust with a rag while the vehicle is running and see if you can see any leaks that way. However, be super careful with this and don’t let the vehicle idle too long in this condition.
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