Fuel Trims - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Joseph92 · 03-31-2013, 02:11 PM

I have a 2011 Camaro 2SS with the L99 enigne.

What should my fuel trims be at normally?

Joseph92 · 04-01-2013, 10:20 AM

Let me tell yall what is going on.

So first of all I have a cold air intake. I have had it for over a year now and never had any problems. About 3 weeks ago my check engine light came on and said that bank 1 and bank 2 where running lean. The dealer said they found a leak around a grommet that is on to the cold air intake to connect a vacuum hose that goes to the engine. Well I got that fixed and then a week later the check engine light came back on. The dealer told me to put the stock air box back on and see what the fuel trims do. So I did that and I started looking at my fuel trims. I know before I put the stock air box back on my long term fuel trims where going all over the place and where very high in the positive numbers.

Now with the stock air box back on the long term fuel trims are not moving around as much. While I was driving I was checking the long term fuel trims again and noticed that when I am driving the long term fuel trims would go up to positive 15 then back down to 5 then up to 10 or 11 and so on, but the highest value that it went to was 15.5.

I know that the long term fuel trims change all the time because of weather, driving, and other things. I just want to know if it is normal for the fuel trims to be changing that much, and what the long term fuel trims should be when working normally.

I also know that a cold air intake would cause the long term fuel trims to be different too, but like I said I have the stock air box back on to check for any vacuum leaks in the system that is not from the cold air intake. That is why I am asking what the fuel trims should be.

sloSS · 04-04-2013, 08:24 AM

I believe 1.0 is even.
A higher number (1.07) means the engine is lean and additional fuel is being added to maintain proper mixture.
A lower number (0.94) means the engine is rich and the ECM is reducing fuel to maintain proper mixture.

Anyone with more knowledge, please feel free to correct my statement

firestone_ss · 04-04-2013, 10:19 PM

3-5 percent is normal 15 is telling you something not quite right.put your old air intake on and see what numbers go to

scites · 04-08-2013, 03:17 AM

they should be in the plus or minus 5 range. the closer to zero the better..

03-31-2013, 02:11 PM	#1
Joseph92 Drives: 2011 Camaro 2SS Join Date: Mar 2011 Location: Houston, Tx Posts: 52	Fuel Trims I have a 2011 Camaro 2SS with the L99 enigne. What should my fuel trims be at normally?

04-01-2013, 10:20 AM	#2
Joseph92 Drives: 2011 Camaro 2SS Join Date: Mar 2011 Location: Houston, Tx Posts: 52	Let me tell yall what is going on. So first of all I have a cold air intake. I have had it for over a year now and never had any problems. About 3 weeks ago my check engine light came on and said that bank 1 and bank 2 where running lean. The dealer said they found a leak around a grommet that is on to the cold air intake to connect a vacuum hose that goes to the engine. Well I got that fixed and then a week later the check engine light came back on. The dealer told me to put the stock air box back on and see what the fuel trims do. So I did that and I started looking at my fuel trims. I know before I put the stock air box back on my long term fuel trims where going all over the place and where very high in the positive numbers. Now with the stock air box back on the long term fuel trims are not moving around as much. While I was driving I was checking the long term fuel trims again and noticed that when I am driving the long term fuel trims would go up to positive 15 then back down to 5 then up to 10 or 11 and so on, but the highest value that it went to was 15.5. I know that the long term fuel trims change all the time because of weather, driving, and other things. I just want to know if it is normal for the fuel trims to be changing that much, and what the long term fuel trims should be when working normally. I also know that a cold air intake would cause the long term fuel trims to be different too, but like I said I have the stock air box back on to check for any vacuum leaks in the system that is not from the cold air intake. That is why I am asking what the fuel trims should be.

04-04-2013, 08:24 AM	#3
sloSS Drives: 2012 Camaro 1SS RS LS3 Join Date: Feb 2012 Location: Atlanta Posts: 254 View My Garage	I believe 1.0 is even. A higher number (1.07) means the engine is lean and additional fuel is being added to maintain proper mixture. A lower number (0.94) means the engine is rich and the ECM is reducing fuel to maintain proper mixture. Anyone with more knowledge, please feel free to correct my statement

04-04-2013, 10:19 PM	#4
firestone_ss Drives: 2010 camaro ss Join Date: May 2009 Location: Tacoma WA Posts: 779	3-5 percent is normal 15 is telling you something not quite right.put your old air intake on and see what numbers go to

04-08-2013, 03:17 AM	#5
scites Drives: 2010 camaro SS/RS Join Date: Dec 2012 Location: swaffham UK Posts: 370	they should be in the plus or minus 5 range. the closer to zero the better..