O2 sensors...
06-26-2011, 02:09 PM
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O2 sensors... I installed Long tubes, ORY, and GMMG. I only have front O2 sensors. I keep getting different info from different people, and I don't know what's legit. Do the rear O2s give me my Long Term Fuel Trim or do they just monitor the life of the cat? I remember being told on ls1tech that it is ok to run just the fronts. The guys at work are telling me I have to buy weld-in O2 bungs, and put them in. Other guys tell me I should buy O2 dummies. Who knows what they are talking about?
Right now my STFT and LTFT are pinned at 128 on my scanner. Accordingly, my car is running rich. I have new O2 sensors in, but they aren't crosscounting, or doing much at all.
When I first installed everything it ran great. It's been down for a long long time, and I'm trying to get it running strong again.
I just got a MAP/BARO code, that could be my whole problem. I'll address that ASAP.
It's also hard to start. and I have to wait about 10 seconds for the computer to adjust my idle before I take off or my RPMS will shoot up to about 1500-2000 everytime I push the clutch in. Does anybody know what exactly the computer wants to see before it will start?
Any help would be greatly appreciated. I'm not asking for the fix, because I may have several problems. Just trying to get some good info before I dive into the thing. Thanks.
Right now my STFT and LTFT are pinned at 128 on my scanner. Accordingly, my car is running rich. I have new O2 sensors in, but they aren't crosscounting, or doing much at all.
When I first installed everything it ran great. It's been down for a long long time, and I'm trying to get it running strong again.
I just got a MAP/BARO code, that could be my whole problem. I'll address that ASAP.
It's also hard to start. and I have to wait about 10 seconds for the computer to adjust my idle before I take off or my RPMS will shoot up to about 1500-2000 everytime I push the clutch in. Does anybody know what exactly the computer wants to see before it will start?
Any help would be greatly appreciated. I'm not asking for the fix, because I may have several problems. Just trying to get some good info before I dive into the thing. Thanks.
06-26-2011, 08:00 PM
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You don't need the rear 02s... period. How ever you need to get them tuned out and get a tune in general if you just did all that exhaust work and aren't going any further.
But anyway, can you post a video of that set up!? I've been debating what catback to go with my lt's and ory. How do you like your's? Is there rasp?
But anyway, can you post a video of that set up!? I've been debating what catback to go with my lt's and ory. How do you like your's? Is there rasp?
06-26-2011, 10:11 PM
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I can. tomorrow. You won't have any regrets going with the GMMG. It sounds awesome WOT. I get compliments everywhere I go...
Last edited by junkindatrunkmx6; 06-26-2011 at 10:17 PM.
06-27-2011, 09:42 AM
#5
Don't believe everything you read on the internet! The GM factory service manual states that the rear O2's are used in the fuel calculations. (They definitely don't have a large influence, though.) Obviously, if you tune them out, that will fool the car in to thinking they are there and happy.
06-27-2011, 09:25 PM
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So no rasp with that setup? How's the idle?
Don't believe everything you read on the internet! The GM factory service manual states that the rear O2's are used in the fuel calculations. (They definitely don't have a large influence, though.) Obviously, if you tune them out, that will fool the car in to thinking they are there and happy.
06-28-2011, 10:28 AM
#7
I doubt that the missing O2 sensors are messing anything up other than giving you a code and/or reporting that your catalyst is bad. If the GM Factory manual is correct, I'd guess that they would help in fine tuning the mix so the catalytic converter will be happiest. The first set of sensors should play a (by far) dominant role in the calculations.
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06-29-2011, 03:40 PM
#8
I have the same setup as you: Longtubes, ORY, and GMMG's. I bought two o2 sims for the rear because there weren't any good tuners in my area. They took care of my check engine light and I'm getting really good mileage and power with just the front o2's. If it's going to be a pain in your ***, you can get away with throwing some sims on there and just making sure your front sensors are legit.
06-29-2011, 07:48 PM
#11
Only been running front 02s, got the rear 02s tuned out 5 years ago, car still running good. Just be prepared to change the front 02s at about every 20,000 miles, at least that's what I get out of these Bosch ones. Real easy to change them out with the right 02 sensor socket tool. The driver's side electrical connector is a bit of a squeeze to get to.
06-30-2011, 02:00 PM
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Thanks for the replies. I swapped my map sensor, and my O2s are new. Anybody know why my car won't go into closed loop? Or why my O2s aren't cross counting? I could really use some help here.
