STFT 2000 Camaro

[Jordan89]

Hi, I am looking for help/advice. I have a 2000 SS Camaro with BBK LT's, Y-pipe that comes with the kit(no cats), K&N FIPK air intake, corvette O2 sensors, and am running E85(Only changed the stoich). I drove the car today with the scanner running, and noticed that the STFT's were at -2.3 on bank two, and 3.9 on bank 1 at 1,463RPM and at 65% throttle. I will try to upload the scan and hope it works. I tried to tune the MAF using a method I found here, but that method only works with VCM 2.22, and I am running the beta version. What do you guys suggest I should do?

[Jordan89]

I just got back from a 20 mile drive to see how the car reacts. As I was drving back home, I got a "system lean bank 1" message. Could it be because of the E85 fuel? I'm probably going to just switch back to gas and hope this will fix the lean issue. Can anybody offer some help? By the way, the AIT got in upwards of 100*F!

[Iam Broke]

You probably have an exhaust leak before or just after the 02 sensor on bank 1 skewing the fuel trims. What are the LTFT's?

Stock injectors are too small to run E85, log your Inj Duty Cycle in a pull, it's prob over 100%, should try to keep it down to the 80% range.

More needs to be done to run E85 then just changing stoich. You need a WB 02 before you blow it up. You will also need to understand tuning in Lambda instead of AFR. Using Lambda, stoich is 1.0 regardless of fuel.

You may have enough fueling to run an E47 blend (1:1 E10 premium & E85 ~99 octane) but without a WB to see what's happening, you are rolling the dice.

[Jordan89]

You probably have an exhaust leak before or just after the 02 sensor on bank 1 skewing the fuel trims. What are the LTFT's?

Stock injectors are too small to run E85, log your Inj Duty Cycle in a pull, it's prob over 100%, should try to keep it down to the 80% range.

More needs to be done to run E85 then just changing stoich. You need a WB 02 before you blow it up. You will also need to understand tuning in Lambda instead of AFR. Using Lambda, stoich is 1.0 regardless of fuel.

You may have enough fueling to run an E47 blend (1:1 E10 premium & E85 ~99 octane) but without a WB to see what's happening, you are rolling the dice.

I had to work today, so I didn't get a chance to check for leaks. I'm probably just going to end up going back to gasoline, and hold off on the E85 until I learn how to tune my car. I don't have a wideband, but will get one ASAP. The STFT's were very lean, most especially under load. I have some green top injectors that I was running prior to adding the headers, but it was still running lean. I have to learn how to add more fuel or something. Do you add fuel on the PE tables to solve this lean issue?

[Jordan89]

Ok, so I went out there really quickly and checked a bit. There is a leak at the exhaust where the Y-pipe meets the back pipe, but could that be causing the lean condition? That's pretty far away from the O2 sensors. I have a bit less then 1/4 tank of E85 left, do you guys think it will run too rich if I add gas and change my stoich back to E10 settings?

[Iam Broke]

You have to get the right injector data in your tune regardless of the fuel you are using or disaster may in sue. Switching fuel if the injector data is bad isn't going to help.

The leak that far downstream prob isn't the issue.

Did you change the injector data when you put the green tops in? If so, where did it come from?

Stock injectors are too small for you to go E85 as it will require ~30% more fuel.

[Jordan89]

You have to get the right injector data in your tune regardless of the fuel you are using or disaster may in sue. Switching fuel if the injector data is bad isn't going to help.

The leak that far downstream prob isn't the issue.

Did you change the injector data when you put the green tops in? If so, where did it come from?

Stock injectors are too small for you to go E85 as it will require ~30% more fuel.

I did change the injector data, and got the data from a tuner(that will go unnamed). I found out that my bank 1 injector isn't switching like it's suppose to, as it will not go higher ~.150V under acceleration.

[Iam Broke]

That's a result, not a cause. You are very lean on B1 so the millivolts stay low.

[Jordan89]

That's a result, not a cause. You are very lean on B1 so the millivolts stay low.

I see. I'm going to have to get a wideband. I have read about how reading, and tuning, for Lambda is less confusing then AFR. So, I need to add fuel pretty much right?

[Iam Broke]

Log your LTFT's & STFT's. Sum the two for each bank. That will give you an idea of where you really are AT CRUISE. Just stating the STFT's doesn't help because the LTFT's adjust to bring the STFT's closer to zero.

Lambda is 1.0 at stoich regardless of fuel. That makes it easier to tune alternative fuels where the AFR for stoich is not what you are used to.

.84 PE Lambda is the same regardless of fuel as well. No more trying to remember all the different stoich AFR's. I learned to tune in Lambda in the 4 cyl turbo world and glad I did.

You need a wideband to tune WOT. Period.

If you have any air infiltration at a head/header flange leak it will cause the 02's to add fuel (positive fuel trims) and make you run very rich even though it sets a lean code. I suspect your LTFT's are very positive or you are running out of fuel pressure/injector to set the lean code if there are no flange leaks.

[Iam Broke]

P.S. I have an Innovate LC-1 WB kit I'll sell for $100, used around 2500 miles. PM me if interested. You'll need HPT pro though.