LS1 running rich on bank 1
06-22-2010, 10:58 PM
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LS1 running rich on bank 1 Hi,
I have an issue with a 2002 LS1 (from a Firebird). It is running rich on one bank, Bank1, in closed loop only (runs fine cold in open loop).
I first tried switching the existing O2 sensors and that made Bank2 deteriorate and run rich, but did not improve Bank1.
I have replaced the MAF and the two O2 sensors with OE parts. Bank1 continues to run rich. I have taken off the fuel rail and tested it and it operates perfectly.
Can anyone shed any light on what I should try next, or if someone can offer a service to resolve?
Thanks so much for reading.
I have an issue with a 2002 LS1 (from a Firebird). It is running rich on one bank, Bank1, in closed loop only (runs fine cold in open loop).
I first tried switching the existing O2 sensors and that made Bank2 deteriorate and run rich, but did not improve Bank1.
I have replaced the MAF and the two O2 sensors with OE parts. Bank1 continues to run rich. I have taken off the fuel rail and tested it and it operates perfectly.
Can anyone shed any light on what I should try next, or if someone can offer a service to resolve?
Thanks so much for reading.
06-23-2010, 05:29 AM
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What are the LTFTs? Is that how you know it is running rich?
If it is good in open loop and falsely rich in closed loop, there is only one thing that makes that happen - O2 feedback. You said you moved the Bank 1 sensor to Bank 2 and it got rich - did you clear the trims when you did it? If not, that is why Bank 1 stayed rich.. You have to clear the trims or it will take awhile to see the changes (they are LONG term fuel trims)... If it isn't the O2 sensor itself doing it, then you need to look at the harness.
If it is good in open loop and falsely rich in closed loop, there is only one thing that makes that happen - O2 feedback. You said you moved the Bank 1 sensor to Bank 2 and it got rich - did you clear the trims when you did it? If not, that is why Bank 1 stayed rich.. You have to clear the trims or it will take awhile to see the changes (they are LONG term fuel trims)... If it isn't the O2 sensor itself doing it, then you need to look at the harness.
06-23-2010, 10:17 AM
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Don't know what you can do with that scanner, sorry... I believe the trims clear if you disconnect the battery for 10 or 15 minutes...
What were you going by to know it was rich?
What were you going by to know it was rich?
06-25-2010, 09:17 AM
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Thank you. I took off the fuel rail to check the injectors to see if there were any leaks. None. The rail (injectors on that bank) is operating correctly.
My assumption is that only O2 sensing can cause this issue, which would mean either a faulty sensor or an exhaust or vacuum leak on that Bank.
Can't find any leaks.
Stumped.
My assumption is that only O2 sensing can cause this issue, which would mean either a faulty sensor or an exhaust or vacuum leak on that Bank.
Can't find any leaks.
Stumped.
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06-25-2010, 10:25 AM
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If you have replaced both sensors, it could still be a wiring issue or a bad connector... best way to find it is to get a scanner on it watching O2 voltage and get someone to wiggle, shake, pull on the wiring harness to see if you can pinpoint it... these kind of problems can be extremely frustrating and hard to find.
Additionally, it sounds like this is a transplant of some sort (not in the 02 Firebird anymore), so if you don't really need to have the O2s to pass emissions, you could always have a good tune done on the car with a wideband and then just leave it in open loop... just an option. This takes out the issue of exhaust leaks and faulty sensors from skewing the feedback and making it falsely rich. Yet, as long as the tune is done right, you get the efficiency of the EFI.
Additionally, it sounds like this is a transplant of some sort (not in the 02 Firebird anymore), so if you don't really need to have the O2s to pass emissions, you could always have a good tune done on the car with a wideband and then just leave it in open loop... just an option. This takes out the issue of exhaust leaks and faulty sensors from skewing the feedback and making it falsely rich. Yet, as long as the tune is done right, you get the efficiency of the EFI.
06-25-2010, 05:16 PM
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Yes the motor/trans is no longer in the Firebird, but it is in a 1997 so I do need to get emissions first to renew license plates.
I am very interested in the "wideband tune". It's not that I wish to drown the world with hydrocarbons, but how do I get that tune?
I am very interested in the "wideband tune". It's not that I wish to drown the world with hydrocarbons, but how do I get that tune?
06-25-2010, 05:52 PM
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In that case, you need to get the O2's working and run it in closed loop to pass. Tuning the car with a wideband enables the tuner to get all of the fueling tables right, so the O2's only have to do minimal correction at part throttle. And it makes sure the air-fuel-ratio is correct for WOT as well. You can get a good tune from a reputable tuner in your area... where are you located?
06-26-2010, 09:43 AM
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I am located in Denver, Colorado. If you could recommend a tuner or at least someone very familiar with LS1s that would be SO much appreciated.
(The cats are almost new, put on one month ago) - could custom manifolds affect the O2 reading? I had to replace the OE logs with custom to get them to exit behind the suspension.
(The cats are almost new, put on one month ago) - could custom manifolds affect the O2 reading? I had to replace the OE logs with custom to get them to exit behind the suspension.
06-27-2010, 05:32 PM
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The only reason I didn't think it was an exhaust leak was because he said way back in the beggining that when he switched the O2 sensor to the other side, the richness followed it...
06-28-2010, 07:42 AM
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That is true. The richness followed the O2 sensor, but I think the complication may be that the original Bank1 O2 sensor was bad also.
Will be taking the manifold off and rewelding it very carefully today.
Thanks again for all of the help, it is truly appreciated.
Will be taking the manifold off and rewelding it very carefully today.
Thanks again for all of the help, it is truly appreciated.
