I was at school today and took the SS up there and plug it into their scan tool they have there, like the ones the dealers have. I was watching the 02s at idle and the first Bank 1 was anywhere from 50-900mv at idle. The first Bank 2 was steady at about 80mv. Both of those O2s are brand new Bocsh wb. When I gave it any gas, Bank 1 would stay a little rich, but the Bank 2 would go a little lean. The STFT was ~2% on Bank 1 and 0% on Bank 2. If you gave it a little gas, STFT would go -5-8% and Bank 2 would go +1-2%. The Long term were both negitive, but Bank 1 was around -10% and Bank 2 was ~-5%.

Other then that, there were no codes and no other problems. I can't understand what is wrong with this car. The only thing I can think of is that I have a Granatelli MAF in there right now. The engine was done by Doug Rippie and he did all the programing.

Any help would be appreciated.
Jeremy

 

Forgot to add one thing. The MAF was reading 8-9 g/s at an 800 rpm idle. The cam is a crane cam with 210/224 112. The heads are ported and it has SLP headers. Right now it has the stock dual cats and 52mm tb.

 

The O2's are supposed to cycle between ~100 and ~800, so that's not THAT far off, although 900 is getting to be a bit excessive, and 50 is a bit low. Air flow is good, 6-10 is normal. I don't really see a problem. I idle between 85 and 810 when everything is going good, so other than going a bit rich apparently, can't say you really have any problems. Not sure about your short term fuel trims, Im used to dealing with numbers between 108 and 160, not percentages... but if they aren't off much (which it doesn't look like they are), then you shouldn't worry about it.

Jonota

 

He indicated that only the Bank 1 pre-cat sensor was moving from 50-900mV (seems normal to me), but the Bank 2 pre-cat sensor was holding "steady" at 80mV. That wouldn't be normal.

How long had the engine been running when you did the scan? Did the scanner indicate "closed loop enabled"? If it didn't, it might indicate that the right bank O2 sensor was a bit slow to warm up, possibly a problem with the heater circuit. When you did the scan at idle, it should have indicated it was in LT fuel trim Cell 16. What were the LTFT's in that Cell (not when you "gave it a little gas", because that would move you to a different Cell)?

I'm a little puzzled by the "Bosch wb" sensors listed.... are you suggeting that you have wide-band sensors?

 

The O2s I wasn't sure on. I knew they veried, but didn't know how much. If the Bank1 is ok, then there must be a problem with Bank2, it just holds stead and doesn't very more then 10mv at most. Usually it stayed right at 80mv. On thing to note though, the Bank2 voltage would change when you gave it gas and it came back down to idle. Say it was at 80mv, give it some gas, and when it came back to idle again it might be 70 or 100. What ever it came to rest at, it would hardly change. Is there a chance that I might have a problem with the Bank2 O2?

 

I had the scanner pluged in and was watching the readout from the sensors for a good 30min. The car was warm, that I am sure of. It was in closed loop. I do have the Bosch wide-band sensors, I did have plans to try and tune it myself, after some mods that never happened, when I got the sensors.

Like I said before, the scanner I used was like the ones used at the dealers. The thing was pluged in the whole time and I was watching the read out from the sensors. None of the other sensors seemed to be out of range or doing anything out of the ordinary, just the O2s. One thing to note was that when it was idling that it showed the BLMs at 16 cn. What that was for, I'm note sure but maybe it will help you guys out.

 

If you managed to figure out how to connect a Bosch planar 5-wire or 6-wire wide-band, with variable frequency/variable current and a 5V output to a stock F-Body OBD-II PCM, you are way beyond the capabilities of most of us here. I doubt we can help you.

 

I was under the impression that it was a wide-band. I got them from O-Reilys, so what ever that meant.

I just can't figure out why the Bank2 O2 is not as responsive as the Bank1 O2?

 

Switch the sensors side-to-side. See if the problem follows the sensor (sensor problem) or stays where it was (wiring, sensor ground, bad heater circuit, running lean). That will help you narrow it down. Are you using excessive anti-sieze (you actually shouldn't use any at all)? Is it "conductive"? Are you overtightening the sensor? Are you contaminating the outside in any way - oil, exhaust fumes?

 

is this 96 or newer.

Some scanners are confusing because if they are set up incorrectly will refer to the bank one post-cat sensor as bank 2.
Not trying to make you sound dumb or anything. I've just seen it happen a lot. Make sure the year is correct, and that the scanner is set up for post cat sensors.

if it's 95 or older and it's getting a steady reading. Than there is definately something wrong with it.

 

I didn't use any anti-sieze, unless some came on the sensor. I'm not burning anything that I'm not suppose to and am not running rich as far as I know.

The scanner is from the College's tech school. My teach use to use this one all the time when he was a mechanic, so he knows it in and out and always has it setup for OBD2 cars and has the right chip in it.

If the wiring is burner though, or is laying on the header cause a problem like this? Which side is the Bank2 sensor on?

 

I "assumed" we were talking about an OBD-II setup, because he mentions "SS" and "first Bank 1" sensor, and used percentages for the LTFT's. It would probably be a good idea to simply include the year of your car, trany type, and any major mods in a "signature" so people would have to "assume" or guess. You have a better chance of getting a correct answer that way. Not sure why people don't do that when they ask a tech question.

 

I forget sometime that people do the OBD1 conversion. I posted most of my mods in my second post, but yes the car is OBD2. I have this Doug Rippie LT1 engine package. I know that he is also the one that programed the PCM. The car is a 1997 Camaro SS, 6spd, full loaded and still has the stock y-pipe with cats.

The only thing I have done is added a Granatelli MAF. I'm not sure if this could be part of the problem. I am thinking about putting the stock unit back in. Could the a bad EGR cause any kind of these problems? I had one go bad on me recently, but it was replaced by the dealer under warranty. Should the post cat O2s vary with the front ones, or should they pretty much stay unchanged?