I installed LGM Headers and RT cats yesterday which use the higher wattage Rear HO2 sensors with adaptors to plug into the harness where the original front HO2 sensors were. The problem is one of the sensors (HO2S11V) is reporting as an average .21v and it should be around .85 - .92v. If the voltages was correct, I would say that I did the sensors swapped between left and right, but because of the bad voltage, I know that is not my problem. The car runs great when it is in open loop mode, but closed loop is goes nuts. Trying to lean out one bank by 20-35% and trying to rich the other bank by 20-35%. I'm using EFILive pro to diagnose my problem and I have logs where the rear HO2 sensors were both working correctly just before I did the swap.

Anyone got any ideas what could be happening? Is it possible that the sensor went bad or got damaged from unbolting and remounting? I've double checked my plugs to make sure they are connected well.

Any help is appreciated.

Regards
2k1vert
:cheers:

 

I'm having O2 sensor issues since I changed to the Kook's LT headers. I have EFILive Pro V5 and I'm trying to understand how this program works. I didn't get a manual or any instructional materal with the software...where can I get info on its operation? I have run several logfiles and my fuel trims consisently go to 20-25. I think this is a problem, but I don't know how to interpret the data.

 

Please keep us all informed. This is more prevalent than you know.
Randy

 

When you installed the o2 sensors in the bungs did you cross them?

From the factory the rear 02's are crossed, meaning that the passenger side harness plugs into the driver side bung and vice versa.

When you install the LG's you no longer cross the harness, meaning the driver side harness will screw into the driver side bung.

Don't ask me how I know this :crazy:

Hope this helps.

 

This pic shows the WRONG way to install the O2.





[Modified by Wt99C5, 6:54 PM 12/29/2003]

 

You guys are right, I reinstalled them like FACTORY. I un-crossed them and the voltages came up and the car ran fine in closed loop mode, well at least for over 2 hours, then it ran rich 11.7 A/F and I saw 9.9% KR and the Open loop - drive went to Open loop - fault and it would not switch back to closed loop until I turned the car off and restarted it. All was well after that. I'm not sure why the KR or fault happened as I had turned red-lined it several times earlier and hit 131 Mph. At peak speed it seemed like it lost power... sort of like the lifters were floating or leaning out.

Time to dig back into "How to understand, service and modify Corvette fuel injection & electronic engine management"

Boy have cars become complex... I've got 20+ years of catching up to do.

Thanks for your advice.

:cheers:

BTW - The LGM long tube instructions clearly told me to connect the driver's side O2 sensor to the drivers side harness.

 

I carefully followed the LGM long tube instructions too - telling me to connect the driver's side 02 sensor to the driver side harness. Are you saying this is not correct? Andy at A&A Covettes said it would LOOK wrong when properly connected IAW the instructions. Did you end up crossing them and having it work properly?

 

You might want to pull one of your plugs now. Mine were soaked Good job! :cheers:

 

AlohaC5.. look at my pic above. It shows the WRONG way to install the O2's

 

HIGHRPM

I added the BANK 1 & BANK2 - side 1 & side 2 gauges along with Short Term Fuel Trim Bank 1 & 2 to Dash -C which allowed me to easy watch what was happening at a glance. The HO2's are already under Dash - B by default, so you can keep an eye on them. If you are running 20-25 which is trying to RICH the mixture, then I would say yes it sounds like you have a problem.

Remember that the O2 reading are only valid when in closed loop, so look at Dash - A FuelSys A & B to see which mode you are operating in.

Good Luck. I'm just a newbie using EFILive Pro 6, but reading the book I mentioned earlier in this thread, I've learned a great deal.


:cheers:

 

HIGHRPM,
Version 5 pro had help via Web Pages under the doc directory and Version 6 pro has help via a PDF. This help is really just how to operate the program. It does nothing to teach you how to use the tool for troubleshooting and tuning. It is up to each of us to learn the in's & out's of Sequential Fuel Injection SFI and Timing in order to be able to begin to use the tool for anything other than a kewl novelty. I hope I'm up for the task because I dropped additional bucks for LS1Edit for the intentions of tuning.

Good Luck again.

 

The only thing to remember is this. We needed an 02 sensor with a longer wire to reach the original front plug. Since we use an 02 simulator in the rear, we have the unused rear 02 sensor which has a long wire.
The plugs are different on the front (flat 4 pin) and the rear (square 4 pin) or we could just use the rear 02 sensors in place of the front 02 sensors.

So, we made a 4 pin square to a 4 pin flat adapter which now turns the original rear 02 sensor into a 4 pin flat sensor, and you can now use it for a front 02 sensor.
Keep in mind that the 02 sensor which plugs into the LEFT collector will now go to the LEFT side of the car's harness, and the 02 sensor that plugs into the RIGHT collector will now go to the RIGHT side of the car.

The confusing part is that the 02 sensors are bolted in the collectors in a way that points them to the WRONG side of the car. ( the 02 in the left collector points to the right side, but it plugs into the LEFT side, which is the same side as the collector which it came from.)

If you plug only one 02 in at a time, you cannot make a mistake. It is frustrating but very simple.

Review: 02 sensor from Left side collector goes to the left side of car.

02 sensor from Right side collector goes to the right side of the car.

The 02 simulators with the 4 pin square plugs go into the plug where the rear 02 sensors previously went. Do this first so you won't get them mixed up.

We have not had any codes that stayed around. In some cases, it is just a bad 02 sensor that needs to be replaced.

THe first thing to check if the car is running bad in closed loop is for proper connections. then check that the wires were tied away from any hot headers. A melted 02 wire will cause the codes. Or a overheated 02 simulator will cause the codes.

Sometimes one small thing like not keeping the wires tied properly away from the hot pipes will cause the entire issue and code setting.

One more thing. If the wires did happen to melt, you might have an 02sensor fuse that is bad.

How do we know all these potential problems? Becuse experience is the best teacher.

I will be glad to answer any phone calls from anyone having problems with the codes, or other install questions.

Check the basic things that I pointed out, and you should be ok.

Thanks
Lou Gigliotti
LGM

 

Is the crossing of the O2 sensors an issue for all LT headers. I have the Stainless Works LT headers and my O2 are crossed. Why dont you cross them on the LG headers? :confused: By the way, that book" Understanding Corvette Fuel injection" rocks. That should be required reading for all Vette owners. :lol: :conehead

 

Thanks for the pic. Turns out mine are installed properly. Drive side 02 to drive side harness and etc. Everything checks out good according to the instructions.

 

If you consider which O2 sensor plug you are connecting to in respect to they way they were wired from the factory it makes sense.

From the factory the front O2 sensor on the drivers side is attached on the manifold just above the collector and plugs into the harness on the drivers side. This is true the passenger side as well. The rear O2 sensors are are crossed before they are run back to harness, so Bank 1 sensor 2 wiring harness plug is on the passenger side and Bank 2 sensor 2 wiring harness is on the drivers side. Since we are switching the original rear O2 sensors for use in the front sensor plugs, we must switch them back to the same side the orignal were located. Okay, I'm sure that I made that more confusing than it should be, but hopefully you get thre gest of it.

:cheers:

 

I believe I have discovered the cause of my 9.9% KR and excessively rich A/F of 11.7 and why EFILive reported Open Loop - Fault. I failed to securely connect the air bridge when installing the Donaldson Blackwing and it blew off of the duct connecting it to the throtle body. Sort of makes sense, overly rich ratio even tho the MAF still metered the correct amount of air flowing, just not all of it was making it into the engine, thus Knock retard. Hey, sounds reasonable right?

I guess when I get the chance and open road I will see if it happens again or if I cured the problem.

:jester

 

Thanks, I applied for the free upgrade to V6 and downloaded and printed the .PDF manual. This should help....just going to have to get familiar with using it. :cheers:

 

Is that book " Corvette Fuel Injection & Electronic Engine Management
1982-2001 " published by Bentley?

 

Yes :yesnod:
ISBN 0-8376-0861-9

 

hey guys,, I got the auto-tap,, but I fudged and did not get EFI live,,,just the enhanced,, can I upgrade????is it worth it,,I hope I never have to use it,,wheee