O2s hanging around 447

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10-19-2013
delbert62

2 Attachment(s)

O2s hanging around 447

I have searched the forum and found a few other people having this same problem but no one seems to have an answer. We have a 5.3 swapped RX7 and we are having problems with O2 sensors. They are hanging between 445 and 449. We changed sensors and they seem to work for about 4 1/2 minutes, then we lost one bank and about a minute later we lost the other bank. this is our third set of sensors. the heater wiring seems to be correct. we have chased the computer wiring countless times. It seems correct. When we unplug the sensors they hold solid at 450. when they are plugged in, they bounce around between 445 and 449. not much different but some. any thoughts would be greatly appreciated. ThanksAttachment 41490 Attachment 41491
Wrong log file. See below
10-19-2013
lwrs10

Looks like they are working great in that log you posted. Have a log of when they quit?
10-19-2013
delbert62

My Bad. I posted the wrong scan. Here is the correct one.
10-19-2013
delbert62

1 Attachment(s)

Here is the correct log. Sorry. New at posting on this forum
10-19-2013
lwrs10

they both quit right after a WOT period. Do you have a wideband on the car? Where are these O2's located?
10-19-2013
delbert62

No wideband. The O2s are in the exhaust pipe about 6" behind 2010 Camaro stock manifolds
10-19-2013
Ben Charles

You guys using a factory harness or an aftermarket harness??
10-19-2013
lwrs10

Quote:

Originally Posted by delbert62

No wideband. The O2s are in the exhaust pipe about 6" behind 2010 Camaro stock manifolds

I think you are running so rich at WOT it burned them up. A wideband would be a great investment. Most of your log has the trims pulling quite a bit of fuel, so a very good possibility its pig rich at WOT.

Thats my guess....since they both quit after going WOT. Another way to see if you are running rich is pull some plugs and see how they look. I would bet they are near the fouled out point.
10-19-2013
delbert62

Quote:

Originally Posted by Ben Charles

You guys using a factory harness or an aftermarket harness??

Modified factory
10-19-2013
delbert62

Quote:

Originally Posted by lwrs10

I think you are running so rich at WOT it burned them up. A wideband would be a great investment. Most of your log has the trims pulling quite a bit of fuel, so a very good possibility its pig rich at WOT.

Thats my guess....since they both quit after going WOT. Another way to see if you are running rich is pull some plugs and see how they look. I would bet they are near the fouled out point.

I will check it out, Thanks
10-19-2013
delbert62

Yea, both the plugs and the O2s are covered in black soot. Checking the injectors and fuel pressure to see if I can find any discrepancies.
10-20-2013
MMGT1

Liquid fuel hitting killing them stone dead I am going to guess as well. Hope not too dumb of a question, but you kept the bung above the mid point of the exhaust piping right? You don't want the sensor anywhere near the bottom of the exhaust pipe, makes it far too easy for liquid fuel in system to make contact with sensor. If liquid hit it, it's toast, guaranteed

Something different there than what I first though. I still think its fuel related, but I think you are going from pig rich to actually a bit lean WOT. Exhaust full of fuel and then hit with a massive amount of lean hot air is throwing fuel right at the sensor frying it. Just what I think, maybe one of the big guys here will see what I see there... look at frame 1944 and then 2769 guys
10-20-2013
lwrs10

Quote:

Originally Posted by delbert62

Yea, both the plugs and the O2s are covered in black soot. Checking the injectors and fuel pressure to see if I can find any discrepancies.

and from looking at your log again, are you sure its running on all 8?

Quote:

Originally Posted by MMGT1

Liquid fuel hitting killing them stone dead I am going to guess as well. Hope not too dumb of a question, but you kept the bung above the mid point of the exhaust piping right? You don't want the sensor anywhere near the bottom of the exhaust pipe, makes it far too easy for liquid fuel in system to make contact with sensor. If liquid hit it, it's toast, guaranteed

Something different there than what I first though. I still think its fuel related, but I think you are going from pig rich to actually a bit lean WOT. Exhaust full of fuel and then hit with a massive amount of lean hot air is throwing fuel right at the sensor frying it. Just what I think, maybe one of the big guys here will see what I see there... look at frame 1944 and then 2769 guys

I think its running on 6 or less cyl in those frames. I would bet he does not have a check engine light hooked up, has not done a CASE relearn, and would have no idea he has a missfire.
10-20-2013
delbert62

Quote:

Originally Posted by MMGT1

Liquid fuel hitting killing them stone dead I am going to guess as well. Hope not too dumb of a question, but you kept the bung above the mid point of the exhaust piping right? You don't want the sensor anywhere near the bottom of the exhaust pipe, makes it far too easy for liquid fuel in system to make contact with sensor. If liquid hit it, it's toast, guaranteed

Not a dumb question, but yes the bungs are just slightly above center in the pipes

Something different there than what I first though. I still think its fuel related, but I think you are going from pig rich to actually a bit lean WOT. Exhaust full of fuel and then hit with a massive amount of lean hot air is throwing fuel right at the sensor frying it. Just what I think, maybe one of the big guys here will see what I see there... look at frame 1944 and then 2769 guys

I also believe it is fuel related. The car is in Illinois and I am in California so we are tuning this via internet. The MIL is hooked up. The cylinder balance is all between 98 and 100% so I don't think it is a misfire. We did a case learn. I am having my son redo a MAF calibration right now. The injectors seem a little higher than mine run @ same RPMs. I appreciate the help and please keep the suggestions coming
10-20-2013
lwrs10

I just took a look at the tune. It needs a ton of work esp in the spark and VE tables. When comparing it to my 5.3 stock file, it is quite different.

What mods does this engine have? I will see what I can come up with tune wise.

Does this car have a returnless fuel system?
10-20-2013
delbert62

Quote:

Originally Posted by lwrs10

I just took a look at the tune. It needs a ton of work esp in the spark and VE tables. When comparing it to my 5.3 stock file, it is quite different.

What mods does this engine have? I will see what I can come up with tune wise.

Does this car have a returnless fuel system?

The fuel system has a return from the Corvette fuel filter/regulator, and a single fuel line running to the fuel rail. It is a 5.3 with a LS1 car intake,stock LS1 injectors, 2010 Camaro stock headers, no Cats, so no rear O2s. The tune we used is the same tune I have in my car with relatively the same mods. Thought i would be a safe starting point.I do have another tune ready to load that has the stock 5.3 fueling and timing tables.
10-20-2013
lwrs10

Quote:

Originally Posted by delbert62

The fuel system has a return from the Corvette fuel filter/regulator, and a single fuel line running to the fuel rail. It is a 5.3 with a LS1 car intake,stock LS1 injectors, 2010 Camaro stock headers, no Cats, so no rear O2s. The tune we used is the same tune I have in my car with relatively the same mods. Thought i would be a safe starting point.I do have another tune ready to load that has the stock 5.3 fueling and timing tables.

I would start with the stock 5.3 tune and go from there. the timing tables need some work. The VE table needs a bit of smoothing, and the secondary VE table does not match the primary. The injector offsets are for a returnless style system, but the IFR is for a return. You are commanding 11.7AFR when it enters PE, which is too rich for an N/A motor. 12.7 would be more like it. You still have all the timing modifiers in there, and those make tuning a lot harder than it needs to be. You still have cat lightoff timing modifiers in there, but you dont have cats. Your idle spark advance does not match your main spark tables. Your inertia factor is zeroed under torque management. All the torque management settings are stock, most people zero those out, and engine abuse is turned on.

Engine missfire codes are turned off in the tune, so if it does have a missfire you would not know.

MAF performance is set to no error reported. This needs to be stock if you are running a MAF,

Your O2 codes for bank 1 and 2 sensor 1 need to be set back to stock. Leave the sensor 2 codes as is.

Thats what I see after a quick glance at your tune. I did not look too far into it.

I will be glad to help get this ironed out if you want.
10-20-2013
delbert62

Lwrs10, Thanks for the input. I will fix this stuff up and let you know how it works out. After talking with my son, this is not the same tune I have it is the tune that was in the ecu when we got it.
02-14-2014
delbert62

Update to this problem if anyone is searching to find an answer to a similar problem. The problem was with the injector scaling. replaced the entire scale with one from a stock 2002 Corvette (same fuel system setup). Seems to have taken care of it. Thanks Lwrs10