pursuit2550 Posted November 3, 2009 Report Share Posted November 3, 2009 I think my o2 sensors are probably going bad. Here is what's going on. I have a wideband and I see it going from 14.5-14.7 to 15.2-16 some times higher. I will be crusing around 50 running fine, come to a stop still fine then I get up to 50 again and it will read 15.2-16, stay there for awhile and then drop to 14.5-14.7. At WOT its fine 11.7. What could this be? I haven't done anything diff. Haven't changed anything out. My SSS was tune about 3000-5000 miles ago and I currently have 58000 miles. If the o2 sensors are the problem and I change them out do I have to retune. Quote Link to comment Share on other sites More sharing options...
misterp Posted November 3, 2009 Report Share Posted November 3, 2009 (edited) You need to log the O2 signal using EFILive or HPT (or similar); if the O2 switchpoints are similar between the two, then I would guess they are fine, OTOH if one is switching at (pretend) 420 and the other is switching at like 500 or 300 then yeah I would suspenct an O2. More than likely the issue is that your O2 switchpoints need to be adjusted to match the new distance from the engine (you have longtubes, the O2s are farther from the engine and running colder and switching at a different point now than the PCM expects and that will affect closed loop AFR big-time). Or, the issue is in your tune. Mr. P. Edited November 3, 2009 by Mr. P. (see edit history) Quote Link to comment Share on other sites More sharing options...
pursuit2550 Posted November 3, 2009 Author Report Share Posted November 3, 2009 (edited) Hey Mr.P, I really don't know much about pcm tune but justin did a cable tune and data logged it. I am sure he took into account what you wrote. I don't remember this happening at the beginning just recent(3-4 days).also I am only running the front o2 sensor if that matters the rears where deleted. As a matter of fact it started when I took off the hose coming from the pass. side valve cover to the maggie intake tube. I added a small kn filter at the valve cover and blocked off the nipple on the tube. I started getting bank1and 2 lean codes so I put the hose back. Now I don't get the code but I noticed what I mentioned above. If I do put new o2 sensors do I have to retune. Thanks Edited November 3, 2009 by BLKSSS (see edit history) Quote Link to comment Share on other sites More sharing options...
8 UR HMI Posted November 3, 2009 Report Share Posted November 3, 2009 (edited) ur rears don not matter. if they are deleted they are fine. if you dont have cats then it doesnt matter. all the rear o2s do is tell whether or not the cats are working efficiently. my truck does something similar and my o2s are bad. change them out but make sure u get oem ones that are direct swap. see if that does it and if not its still a good idea to have a new set take out ur o2s and see if they are covered in carbon (black residue on the tip). if they are BLACK as can be then they are probably bad. and as long as they are oem direct swap ones u wont need a retune unless the tune was to compensate for the bad o2s. the tune should relearn the new o2s. im swapping mine without a retune and im gonna see how that goes. Edited November 3, 2009 by 8 UR HMI (see edit history) Quote Link to comment Share on other sites More sharing options...
pursuit2550 Posted November 4, 2009 Author Report Share Posted November 4, 2009 I just took them out and the only black carbon residue was around the top near the threads. It was normal around the holes. I went ahead and sand blasted them anyways just to be sure. I will test them tonite to se if there is a biff. Also the WOT is off now. Its at around 11.9-12.2. Quote Link to comment Share on other sites More sharing options...
8 UR HMI Posted November 5, 2009 Report Share Posted November 5, 2009 11.9-12.2 is a little lean for boost. ur o2s. sound fine but just check when u change them that everything is off of them and u dont touch the heads with ur hand when u put them in. Quote Link to comment Share on other sites More sharing options...
misterp Posted November 5, 2009 Report Share Posted November 5, 2009 I just took them out and the only black carbon residue was around the top near the threads. It was normal around the holes. I went ahead and sand blasted them anyways just to be sure. I will test them tonite to se if there is a biff. Also the WOT is off now. Its at around 11.9-12.2. Your factory O2's have ABSOLUTELY NO bearing on your WOT fueling; you are off about 10%, my first suspicion would be that your PCM is tuned for 100% gasoline, but you are running gas with 10% alcohol. Mr. P. Quote Link to comment Share on other sites More sharing options...
pursuit2550 Posted November 5, 2009 Author Report Share Posted November 5, 2009 I run 93 with 10% ethanol, same as when justin tuned it. Maybe I will have to try a diff. gas station. I might be wrong here but isnt gas mixed diff. for winter time. I got the tune back in july-august. So if my o2s are not working at WOT you think it could be the gas. I was driving home today and same thing 11.9-12.2@WOT. This is not good just when the truck was runnig great and the cooler weather was coming to miami. Any help would be a great. Right now I just dont want to buy 200 bucks worth of sensors and turns out it wasnt the problem. Thanks so far for the input guys. Quote Link to comment Share on other sites More sharing options...
pursuit2550 Posted November 6, 2009 Author Report Share Posted November 6, 2009 Come on guys give some suggestions. Also is it bad to be running at 12.2WOT? Quote Link to comment Share on other sites More sharing options...
misterp Posted November 6, 2009 Report Share Posted November 6, 2009 (edited) With a 3" pulley on your Radix I'm gonna say it's borderline running 12.2:1 AFR; it's not the best situation, but you aren't making more than 6-ish psi boost and as long as the IATs are not outta hand and you don't have knock (from bad fuel) then I doubt you will shatter a piston or burn down the motor, but again that's borderline and yeah I would want to improve the situation. But at 12.2:1 you are definitely on the edge of what is acceptable for AFR under boost, you don't have a lot of 'thermal cushion' carrying the extra risidual heat out of the combustion chamber. Yes fuels have to change during the fall, most of the country is already on winter blend but your area probably got cold enough that your local gasoline distributor changed formulas, and yes winter gas is worse than summer blend gas however we need it or else engines won't start when cold. I would run out the fuel you have in the truck now and get your next fill-up at a Chevron station that does a lot of volume, that way you know you have fresh 100% gasoline and see where your AFRs move to. Mr. P. And veryify with Justin that you had your stochiometric ratio set to 14.0:1 instead of 14.7:1 in your PCM, because you run ethanol blend fuels. Edited November 6, 2009 by Mr. P. (see edit history) Quote Link to comment Share on other sites More sharing options...
pursuit2550 Posted November 6, 2009 Author Report Share Posted November 6, 2009 Mr.P thanks for the input it is greatly appreciated. I am running 7-7.5 on boost. I am in miami and I don't see why they would use diff. gas it never gets cold down here but I guess the oil companys down want to make 2 diff. batches of gas. I guess I will have to stay of the throttle till I get this resolved. My IAT are at around 98-104 crusing and get up to around 130-140 at WOT. I have a Areoforce gauge so I was monitoring my KR and its pulling around 2.5-4. I will empty the tank and refill with fresh gas I hope that is my problem. I will also email justin on the setting you talk about. Again thanks and I will write back with the results this weekend. Quote Link to comment Share on other sites More sharing options...
misterp Posted November 6, 2009 Report Share Posted November 6, 2009 ... I have a Areoforce gauge so I was monitoring my KR and its pulling around 2.5-4. ... That's NOT GOOD, you need to get KR down to under 1-degree (ideally). From working with Justin directly, I know that he is conservative on his timing so I am very surprised to hear this; either your ignition timing is way off for the fuel you are actually running. Mr. P. Quote Link to comment Share on other sites More sharing options...
pursuit2550 Posted November 8, 2009 Author Report Share Posted November 8, 2009 I think I found my problem. I decided to use my aeroforce gauge and monitor my o2 sensors and I have no reading from the bank 2 sensor. Bank 1 which is s1b1 on the gauge is showing a reading. When I switch to s1B2 I get no reading. So I guess I an going to have to change my sensors. Quote Link to comment Share on other sites More sharing options...
zippy Posted November 8, 2009 Report Share Posted November 8, 2009 Your factory O2's have ABSOLUTELY NO bearing on your WOT fueling; you are off about 10%, my first suspicion would be that your PCM is tuned for 100% gasoline, but you are running gas with 10% alcohol. Mr. P. That's not true at all. Long term fuel trims can and do have an effect during power enrichment. O2 readings are where the long term fuel trims come from. As for the difference in fuel, I'm sure his station was likely already running 10% ethanol like almost every gas station out there does all year round. The LTFT's compensate for that difference by design if the maf calibration and v.e. table is correct. Quote Link to comment Share on other sites More sharing options...
misterp Posted November 8, 2009 Report Share Posted November 8, 2009 That's not true at all. Long term fuel trims can and do have an effect during power enrichment. ... Good point Zippy, that didn't occur to me at all. Mr. P. Quote Link to comment Share on other sites More sharing options...
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