73 replies to this topic

[xrocketengineer]

I can not see the video. It asks for a log in.  Anyway, here is some very good information on oxygen sensors. It even has a test at the end.  

http://www.autoshop1...m/forms/h37.pdf

[brivinci]

The video is public. Maybe you have to be logged into YouTube. A coworker just got on and viewed the video with no problems.

 

When you said test, I thought you meant how to test, not take a test on the material:-)

 

I am not sure this will answer my question. I tested mine using a scanner (same as yours) and it shows the Lambda switching from high to low. Wonder if it is not doing it quick enough and if that might be a problem. OR, is it only if the lambda stays on a high or low voltage that you will see a problem?

[Fast Ivan]

I can't view the video either, and I'm logged in.

anyways the lambda should fluctuate from high to low quickly, so quickly that you can't actually make out all of the steps (if that's the correct term?) but you will be able to pick up some of them. it should be going from rich to lean, or high reading to low in milliseconds.

a faulty lambda can read high, low or be sluggish

Edited by Rob Mac, 07 August 2013 - 08:30 PM.

[brivinci]

I wonder what the deal is with the video? Darn YouTube!!

 

Well, I can tell that mine still goes from low to high BUT is very sluggish then. I can watch it read and it actually stays on high or low for a full second or so. Really wish you could see the video. What a pain.

[Fast Ivan]

therein may lie your problem. do you have an lcb fitted?

[brivinci]

I do in fact. Why?

 

It wasnt easy getting my lambda out if I recall but it look sound enough.

[Fast Ivan]

just trying to gather info on lambda positions and readings.

I'm guessing the lambda isn't in the Y piece? (don't assume this is your problem please!!)

Be good to sort that vid though if you can

[brivinci]

The header is from Maniflow. I believe it is located at the bottom of the Y, after they come together. Can check on that.

 

Try this link, and if not, try searching Rover Mini SPi Lambda. Mine should be the latest one posted.

 

[Fast Ivan]

the vid works now.

maybe the problem here is that the reader you have is displaying volts as apposed to millivolts, which is what the lambda output is measured in. so it looks sluggish as its fluctuating in steps of 0.1V.

I'll compare it with other readings I have tomorrow and let you know my thoughts

[IainStallard]

My lambda is exactly the same, only faster to switch high and low

[xrocketengineer]

This time the video worked. For what it is worth, I have been troubleshooting an Oxygen sensor on my Nissan Titan. The sensor is the downstream one from the cat that checks the cat's efficiency. The first time I got a code, it threw me off telling me the cat was bad (only 22,000 miles!). After a couple of resets of the failure, then it started showing a different code that could be related to a bad sensor. And that started to make more sense. Well, per the Nissan repair manual, the sensor should go down to 0.18 Volts (lean) at least once when coasting from 50 mph. My right sensor, being a V8, would never go that low but the left one would. Additionally, when the engine would be started the right sensor would be reading above 1.2 Volts while the left one would be reading like 0.3 volts. Per the Nissan manual and the Toyota info, a sensor operating properly shows reading from 0 Volts to 1 Volt. Readings above that, per the Nissan manual, indicate a failed sensor or wiring. I swapped the sensors from left to right on my truck and all the issues moved from the right side to the left. I replaced the right sensor with a new Bosch one and even though the the readings on the two sides are not a perfect match, I have 0 Volts on both sides during deceleration and never a reading above 1.0 volts.

So, I think that your Lambda sensor is bad.  I would disconnect the sensor and see how it runs. 

Edited by xrocketengineer, 07 August 2013 - 10:03 PM.

[brivinci]

I will try and disconnect it but I am wondering what I will find, being that my car is already running rich. If it runs exactly the same, would that mean that my 02 sensor is in fact bad?

[firstforward]

Probability yes but not necessarily.

[xrocketengineer]

If it still runs the same, you might have other issues. Here is one example: another (former?) member of TMF had problems with an MPI that blew smoke after a rebuild. I believe the smoke was white. After many attempted fixes he found that his brake servo diaphragm was leaking and also is master cylinder. The engine had swallowed so much brake fluid that apparently it ruined a lot of the engine seals and his piston rings never broke in properly. He never recovered from that one and sold the car.

As far as the oxygen sensor goes, it is there only to ensure that the mixture is as close to stoichiometric (14.7 to 1) so the catalytic converter can do its job. The MAP sensor, CPS, TPS, AIT and CTS are the parameters used for the mixture. That is how the early fuel injection systems operated with even more primitive sensor schemes.

My daughter's Hyundai was driving really bad, with some black smoke coming out of the exhaust. Initially, there were no codes but when finally I got something it was related to "fuel out of parameters".  At the time my diagnostics (Scan Gauge now can on newer cars) could not read the oxygen sensor values but it could tell me when the engine would go into "close loop". Interestingly, the engine would run fine for a minute or so and then it would go bad. The engine would start running rough exactly when it would go into "close loop" using the sensor. So, I disconnected the sensor, the check engine light came on and the car ran perfectly! A new sensor solved the problem.

In your case, you have no catalytic converter so there is no concern with emissions or damaging it. Disconnecting the oxygen sensor eliminates a variable that could be the cause of your problems or at least it will not interfere with any further troubleshooting that you might need to do. 

Edited by xrocketengineer, 08 August 2013 - 04:21 PM.

[xrocketengineer]

More information on Oxygen sensors:

http://www.autodiagn...sor-testing.htm

It says that the sensor should be cycling at least once per second. When looking at your video, and using the 0.45 Volt threshold, the first cycle starts at 2 seconds (0.5 - 0.4 Volts going down) then at 4 seconds crosses again (0.2 - 1.1 Volts going up) and at 8 seconds completes the cycle (0.6 - 0.2 Volts going down). That is a total of 6 seconds for one cycle the next one is 7 seconds. So it looks like the sensor is cycling too slowly.