Wideband O2 Sensor Installation

[Greg L.]

I would like to temporarily install a wideband O2 sensor on my 69 L36 and was wondering if it really needs to be installed closer to the engine... I do not want to remove the pipe from the exhaust manifold just to weld in a bung for the sensor and would prefer to install it at the tailpipe. I was thinking I would be okay to remove a tailpipe and install a "test tailpipe" with a bung for the sensor.

Has anyone done this with success? Any thoughts or advice is appreciated.

Thanks!

[Edward J.]

Re: Wideband O2 Sensor Installation

Greg, there’s a lot of help on you tube for sensor placement.

[Joe L.]

Re: Wideband O2 Sensor Installation

I would like to temporarily install a wideband O2 sensor on my 69 L36 and was wondering if it really needs to be installed closer to the engine... I do not want to remove the pipe from the exhaust manifold just to weld in a bung for the sensor and would prefer to install it at the tailpipe. I was thinking I would be okay to remove a tailpipe and install a "test tailpipe" with a bung for the sensor.

Has anyone done this with success? Any thoughts or advice is appreciated.

Thanks!

Greg------


If by "tailpipe" you are referring to the exhaust extension (tip), I think that's too far back in the system to work properly.

One thing that I think MIGHT work is to obtain a a right side exhaust spacer (or, gutted old heat riser valve) and modify it to accept the O2 sensor. I've never done this, though; it's just a thought.

Of course, you could drill and weld a threaded bung onto a forward exhaust pipe simulating the installation often seen on modern cars. However, when you're done you'll still have the bung which you'll have to plug.

[David H.]

Re: Wideband O2 Sensor Installation

I would like to temporarily install a wideband O2 sensor on my 69 L36 and was wondering if it really needs to be installed closer to the engine... I do not want to remove the pipe from the exhaust manifold just to weld in a bung for the sensor and would prefer to install it at the tailpipe. I was thinking I would be okay to remove a tailpipe and install a "test tailpipe" with a bung for the sensor.

Has anyone done this with success? Any thoughts or advice is appreciated.

Thanks!

Greg

O2 sensor purpose? Is it for air/fuel ratio measurements?

If so, there are several "YouTube" videos with folks using an Innova sensor/monitor.

Did not require modification to exhaust. Search YouTube for "Corvette air fuel ratio".

One I watched was by "CorvetteHop".

Dave

[Jim L.]

Re: Wideband O2 Sensor Installation

I would like to temporarily install a wideband O2 sensor on my 69 L36 and was wondering if it really needs to be installed closer to the engine... I do not want to remove the pipe from the exhaust manifold just to weld in a bung for the sensor and would prefer to install it at the tailpipe. I was thinking I would be okay to remove a tailpipe and install a "test tailpipe" with a bung for the sensor.

Has anyone done this with success? Any thoughts or advice is appreciated.

Thanks!

Greg,
I regularly use wideband 02 sensors and gauges when I calibrate Rochester FI units. All are mounted at the exit of the tailpipe. My results are always good.

To mount the O2 sensor at the tailpipe outlet, you need what Innovate Motorsports calls an "exhaust clamp".
exhaust_clamp.jpg

I have found that in order to produce reliable, believable air/fuel readings at engine idle, I need to have an extension on the clamp so that the reading isn't diluted by ambient air due to reversion. I made one out of 5/8" soft copper tubing:

4064-re.jpg

When installed on my '60, the whole assembly looks like this:

7291-re.jpg

I strongly recommend AGAINST installing the sensor in a dummy heat riser valve. That location is too close to the engine for the control electronics of the gauge to regulate the sensor temperature. If the control electronics can't regulate sensor temperature, you won't get accurate air/fuel readings and sensor life will be compromised.

If you have any questions, just ask.

Jim

[Greg L.]

Re: Wideband O2 Sensor Installation

Thanks a lot guys.

I had done some Google searching and was leaning towards the Innovate LM-2. It seems pretty straight forward to use but the general internet consensus was that locating the O2 sensor near the tail pipe wouldn't give proper readings because the gasses wouldn't be hot enough or because it would suck in ambient air at the pipe and skew the readings. It was a relief to know that Jim has confirmed that if properly set up, this method at the tailpipe will work.

Now just one other question that I just thought of... The engine is bone stock and has a restored A.I.R system installed. When checking for proper A/F mixture(not for emissions) I would guess that the system should be deactivated and capped at the check valves. If not, this will skew the A/F readings by pumping in additional fresh air into the exhaust, correct?

[Joe L.]

Re: Wideband O2 Sensor Installation

Greg,






I strongly recommend AGAINST installing the sensor in a dummy heat riser valve. That location is too close to the engine for the control electronics of the gauge to regulate the sensor temperature. If the control electronics can't regulate sensor temperature, you won't get accurate air/fuel readings and sensor life will be compromised.



Jim

Jim------

This surprises me. Many modern vehicles have the upstream oxygen sensor mounted either in the exhaust manifold or in the header pipe very close to the exhaust manifold. In fact, three of my vehicles which have oxygen sensors are like this. My Pontiac Grand Prix with supercharged 3.8L V-6 has the oxygen sensor threaded directly into the rear exhaust manifold. My Cadillac Eldorado has the oxygen sensor mounted in the header pipe about 2" below the manifold and my 1992 Corvette has the oxygen sensors mounted in the header pipes about 3" below the manifolds. I've had no problems, at all, with them. In fact, in all three cars I've never had to replace one.

[Joe L.]

Re: Wideband O2 Sensor Installation

Thanks a lot guys.


Now just one other question that I just thought of... The engine is bone stock and has a restored A.I.R system installed. When checking for proper A/F mixture(not for emissions) I would guess that the system should be deactivated and capped at the check valves. If not, this will skew the A/F readings by pumping in additional fresh air into the exhaust, correct?

Greg------


I would say yes. However, all you should need to do is to remove the belt from the pump or simply remove the flexible hoses at the check valves. If the check valves are operating properly there shouldn't be a need to cap them as they will prevent any exhaust outflow. In fact, if you remove the hoses this will give you a good chance to check the check valves for proper operation. If there is any exhaust flow through them then you need new valves(s). Defective check valves will cause the destruction of the diverter valve and AIR pump. You DEFINITELY don't want to destroy the diverter valve.

[Jim L.]

Re: Wideband O2 Sensor Installation

Jim------

This surprises me. Many modern vehicles have the upstream oxygen sensor mounted either in the exhaust manifold or in the header pipe very close to the exhaust manifold. In fact, three of my vehicles which have oxygen sensors are like this. My Pontiac Grand Prix with supercharged 3.8L V-6 has the oxygen sensor threaded directly into the rear exhaust manifold. My Cadillac Eldorado has the oxygen sensor mounted in the header pipe about 2" below the manifold and my 1992 Corvette has the oxygen sensors mounted in the header pipes about 3" below the manifolds. I've had no problems, at all, with them. In fact, in all three cars I've never had to replace one.

Without seeing those installations, Joe, I don't know what to tell you.

Innovate Motorsports, the supplier of the equipment on which I depend, is quite clear about preventing the sensor from overheating. In fact, for sensors located in an exhaust pipe bung at some distance from the manifold, they include instructions for crafting a heat sink to reduce sensor heating due to engine proximity.

I take them at their word since I've obtained excellent results by following their guidance.

Jim

[George J.]

Re: Wideband O2 Sensor Installation

Greg,
I regularly use wideband 02 sensors and gauges when I calibrate Rochester FI units. All are mounted at the exit of the tailpipe. My results are always good.

To mount the O2 sensor at the tailpipe outlet, you need what Innovate Motorsports calls an "exhaust clamp".
[ATTACH=CONFIG]110220[/ATTACH]

I have found that in order to produce reliable, believable air/fuel readings at engine idle, I need to have an extension on the clamp so that the reading isn't diluted by ambient air due to reversion. I made one out of 5/8" soft copper tubing:

[ATTACH=CONFIG]110221[/ATTACH]

When installed on my '60, the whole assembly looks like this:

[ATTACH=CONFIG]110222[/ATTACH]

I strongly recommend AGAINST installing the sensor in a dummy heat riser valve. That location is too close to the engine for the control electronics of the gauge to regulate the sensor temperature. If the control electronics can't regulate sensor temperature, you won't get accurate air/fuel readings and sensor life will be compromised.

If you have any questions, just ask.

Jim

Jim,
I am trying to replicate your extension, and have obtained the 5/8" copper tubing, but it is still a little larger than the LM-2 exhaust extension, and the clamp I have does not have the force to compress the tubing. Do you have any suggestions, or tricks as to how you were able to make it work? Thanks.

George

[Jim L.]

Re: Wideband O2 Sensor Installation

Jim,
I am trying to replicate your extension, and have obtained the 5/8" copper tubing, but it is still a little larger than the LM-2 exhaust extension, and the clamp I have does not have the force to compress the tubing. Do you have any suggestions, or tricks as to how you were able to make it work? Thanks.

George

George,

I used a hacksaw to cut a longitudinal slot in the copper tube. That made it possible for the clamp to distort the tube and grip the Innovate adapter.

Jim

[George J.]

Re: Wideband O2 Sensor Installation

George,

I used a hacksaw to cut a longitudinal slot in the copper tube. That made it possible for the clamp to distort the tube and grip the Innovate adapter.

Jim

Jim,
thank you, very much! I was able to get fairly good results last night using the exhaust attachment, on my '65 sidepipe car when cruising and at full throttle. I will try to get the extension to work using your tip.
When you are tuning for each stop, economy and power, at what rpm, and in what gear, are you using? This is a Fuel Injected car with the 30-30 cam.

George

[Jim L.]

Re: Wideband O2 Sensor Installation

Jim,
thank you, very much! I was able to get fairly good results last night using the exhaust attachment, on my '65 sidepipe car when cruising and at full throttle. I will try to get the extension to work using your tip.
When you are tuning for each stop, economy and power, at what rpm, and in what gear, are you using? This is a Fuel Injected car with the 30-30 cam.

George

To set the Economy Stop, I drive at a steady highway speed on a stretch of road with a slight up-grade and note the AFR. The up-grade is important. It needs to be steep enough that the throttle opens far enough to shut down the idle boost circuit, but not so steep that the Ratio Lever begins to transition to the Power Stop. My eyeball guess is that the stretch of road I use has a 1% - 2% grade. I'm looking for an AFR of ~15.3:1. I drive, measure, and adjust until I achieve that ratio.

I use the same stretch of road when I adjust the Power Stop. I go wide-open-throttle and, again, note the AFR. Extensive dyno experiments performed by Jerry Bramlett showed that FI engines make their best power with an AFR of 13:1. I adjust for that ratio altho sometimes I call it good at 12.8:1, 12.9:1. My accelerometer can't detect a meaningful difference due to any of those ratios as long as they are in that range. In any event, I never let the AFR go any more lean than 13:1.

After you have the Economy Stop adjusted, you can adjust the trip point of the Enrichment Diaphragm & Ratio Lever. For the 30-30 cam, you want Ratio Lever to just reach the Economy Stop when vacuum applied to the Enrichment Diaphragm reaches 7" Hg.

[George J.]

Re: Wideband O2 Sensor Installation

To set the Economy Stop, I drive at a steady highway speed on a stretch of road with a slight up-grade and note the AFR. The up-grade is important. It needs to be steep enough that the throttle opens far enough to shut down the idle boost circuit, but not so steep that the Ratio Lever begins to transition to the Power Stop. My eyeball guess is that the stretch of road I use has a 1% - 2% grade. I'm looking for an AFR of ~15.3:1. I drive, measure, and adjust until I achieve that ratio.

I use the same stretch of road when I adjust the Power Stop. I go wide-open-throttle and, again, note the AFR. Extensive dyno experiments performed by Jerry Bramlett showed that FI engines make their best power with an AFR of 13:1. I adjust for that ratio altho sometimes I call it good at 12.8:1, 12.9:1. My accelerometer can't detect a meaningful difference due to any of those ratios as long as they are in that range. In any event, I never let the AFR go any more lean than 13:1.

After you have the Economy Stop adjusted, you can adjust the trip point of the Enrichment Diaphragm & Ratio Lever. For the 30-30 cam, you want Ratio Lever to just reach the Economy Stop when vacuum applied to the Enrichment Diaphragm reaches 7" Hg.

Jim,
thank you, very much. This is great information and I really appreciate it. Can I assume all of these measurements are done in 4th gear?

George

[Jim L.]

Re: Wideband O2 Sensor Installation

Jim,
thank you, very much. This is great information and I really appreciate it. Can I assume all of these measurements are done in 4th gear?

George

4th gear is what I recommend when measuring the cruise AFR. For checking WOT AFR, you can use 2nd or 3rd gear so your vehicle speed doesn't reach "unauthorized" levels.