Banks 1 and 2 lean - engine light on
Thread Starter
Burning Brakes
Joined: May 2008
Posts: 1,043
Likes: 1
From: Houston TX
Banks 1 and 2 lean - engine light on
Just got my car going again after the hydro lock and the engine light keeps coming on. Says bank 1 and 2 too lean. Was suggested to use some MAF cleaner on the MAF bc it could be dirty. Also maybe the front o2s? Rear o2s are tuned out. Heard maybe even the tune?
Anyone have an idea before I just replace the o2 sensors?
Thanks
Anyone have an idea before I just replace the o2 sensors?
Thanks
Melting Slicks
Joined: Aug 2006
Posts: 2,167
Likes: 11
From: Powell TN
Cruise-In VIII Veteran
You have an air leak somewhere. Your rear 02s have nothing to do with your AFR, their sole purpose is to monitor the cats.
Thread Starter
Burning Brakes
Joined: May 2008
Posts: 1,043
Likes: 1
From: Houston TX
Thread Starter
Burning Brakes
Joined: May 2008
Posts: 1,043
Likes: 1
From: Houston TX
Thread Starter
Burning Brakes
Joined: May 2008
Posts: 1,043
Likes: 1
From: Houston TX
Thanks Tx Vette and 2000 c5 I'll check for an air leak. Only thing is that the light took several days from getting it back to actually come on.
I cleaned the MAF and reset the light, it stayed off for several hours and came back on. Oh well.
I cleaned the MAF and reset the light, it stayed off for several hours and came back on. Oh well.
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Le Mans Master
Joined: Jul 2007
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From: Arkansas
St. Jude Donor '09 thru '17,'22 thru '26
After getting the same lean codes I discovered this line had split. My codes popped up after some engine idle time-raised the hood and could easily hear the sucking sound. New hose took care of it, I used 3/8" fuel line while the correct hose was on order.
Thread Starter
Burning Brakes
Joined: May 2008
Posts: 1,043
Likes: 1
From: Houston TX
Hmmm I cant find any vacuum leaks. I used to find them by spraying some brake cleaner around the motor but dont think thats going to fly on a Corvette. Any easy but safe ways to find a leak? I just installed a catch can so I dont think the u shaped line is leaking air. All the lines have a hose clamp except the bottom line bc I could reach it with a screwdriver. I'll try to take that apart tonight and see if it fixes it.
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
If you have a steady idle, you dont have a leak. Even if it did have a leak the car would then add fuel to make it hit stoic or in your case, where the long term fuel trends are set to center at. A leak wouldnt throw it off 24%. The valley air hose to the intake manifold would only increase it by +10 but you would hear that from 10 feet away.
The car needs to be tuned properly. It was likely on the line of not tripping the code (+20%) and then the new air cleaner that you likely put in after the water hit made it run leaner in closed loop. The scan will show it doing that only at some particular rpm and not tuned across the full MAF range. Adjust the MAF table for that frequency cell up 20%, smooth it, and the code will never come back.
The car needs to be tuned properly. It was likely on the line of not tripping the code (+20%) and then the new air cleaner that you likely put in after the water hit made it run leaner in closed loop. The scan will show it doing that only at some particular rpm and not tuned across the full MAF range. Adjust the MAF table for that frequency cell up 20%, smooth it, and the code will never come back.
Thread Starter
Burning Brakes
Joined: May 2008
Posts: 1,043
Likes: 1
From: Houston TX
If you have a steady idle, you dont have a leak. Even if it did have a leak the car would then add fuel to make it hit stoic or in your case, where the long term fuel trends are set to center at. A leak wouldnt throw it off 24%. The valley air hose to the intake manifold would only increase it by +10 but you would hear that from 10 feet away.
The car needs to be tuned properly. It was likely on the line of not tripping the code (+20%) and then the new air cleaner that you likely put in after the water hit made it run leaner in closed loop. The scan will show it doing that only at some particular rpm and not tuned across the full MAF range. Adjust the MAF table for that frequency cell up 20%, smooth it, and the code will never come back.
The car needs to be tuned properly. It was likely on the line of not tripping the code (+20%) and then the new air cleaner that you likely put in after the water hit made it run leaner in closed loop. The scan will show it doing that only at some particular rpm and not tuned across the full MAF range. Adjust the MAF table for that frequency cell up 20%, smooth it, and the code will never come back.
So you dont think it could be the front 02s? I did hydrolock the engine and Im using the same 02s.
If not Im going to have to take it back to Texas Speed so they can dyno tune it (all I got was a base tune from them) or have someone else tune it.
You think its bad to drive like it is now?
Burning Brakes
Joined: Jul 2005
Posts: 988
Likes: 26
From: Seattle WA
Check for leaks around air intake to throttle body, ie if you have a Vararam the spacer can bulge and cause a leak, check components/connections along the way. If this started after some changes ie any mod its probably tune time. How did you hydrolock the engine?
Melting Slicks
Joined: Aug 2006
Posts: 2,167
Likes: 11
From: Powell TN
Cruise-In VIII Veteran
I have a flood car that was completely submerged in salt water for days (Katrina), then sat for 3 years before I got it. One of the 02s in it still worked (I replaced them anyway). I would say very little water got through the motor before it locked to harm the 02s, but, one option you have is to put the rear 02s in the front, with a harness adapter and put plugs in the rear holes if you still have them. The rear 02s are more resilient to water since water is one of the byproducts of a catalytic converter.
Tech Contributor
Joined: Mar 2003
Posts: 12,094
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From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
So you dont think it could be the front 02s? I did hydrolock the engine and Im using the same 02s.
If not Im going to have to take it back to Texas Speed so they can dyno tune it (all I got was a base tune from them) or have someone else tune it.
You think its bad to drive like it is now?
If not Im going to have to take it back to Texas Speed so they can dyno tune it (all I got was a base tune from them) or have someone else tune it.
You think its bad to drive like it is now?
You can debate all you want but a scan is worth a thousand posts. If the O2's are bouncing up and down on the scan, they're working. Scan it and do the simple fix.
Its a hundred one way and a hundred the other. If you were here, I'd do it for free. Your car doesnt need a full tune. Its a MAF table tweak.
Yes its bad to drive the car with a lean code.
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
I'm repeating myself.
I wish I had a dollar for every vette running around with +20% long term fuel trends.
Le Mans Master
Joined: Jul 2005
Posts: 5,328
Likes: 405
I have a flood car that was completely submerged in salt water for days (Katrina), then sat for 3 years before I got it. One of the 02s in it still worked (I replaced them anyway). I would say very little water got through the motor before it locked to harm the 02s, but, one option you have is to put the rear 02s in the front, with a harness adapter and put plugs in the rear holes if you still have them. The rear 02s are more resilient to water since water is one of the byproducts of a catalytic converter.
Anyway, I don't see the reasoning for the rear O2 sensors being more resilient to water since the front O2 sensors see a majority of the water vapor that comes out the exhaust.
Last edited by glass slipper; Dec 5, 2008 at 07:49 PM.
Melting Slicks
Joined: Aug 2006
Posts: 2,167
Likes: 11
From: Powell TN
Cruise-In VIII Veteran
This is the common answer that I have heard as to the differences between the front and rear 02s. Assuming this is correct, I figured that since water is produced under normal combustion and the cat also combines atoms to form water molecules, then the rear 02s were exposed to a higher concentration of water. Also, with the rear 02s being in closer proximity to the water production, combined with the lower exhaust temps caused by the converter, it seems this would lead to higher concentrations of water.
Your thoughts?
Former Vendor
Joined: Feb 2007
Posts: 2,572
Likes: 1
From: Austin Texas
My experience with my own car is a leak from the PCV line will cause lean conditions on both banks and idles normally. I installed the PCV catch can and the line going into the intake popped off. While going to lunch, the SES came on and stopped by Autozone. The codes were for fuel trim lean for both banks. Reconnected the hose and the codes cleared themselves after a few ignition cycles. Also, the Vararam Spacer leak is unmetered air since it is downstream of the MAF.