o2 sensor

[pushkick]

if you disconnect your o2 sensor from cat and you remove your cat convertor how will the engine run lean or rich or will it run at all?
_________________
i see said the blind man to his deaf dog
i am going to quit smoking and drinking and die a healthy man. gotta laugh
there is no deed to the planet earth
1990 vw automatic camper

[insyncro]

Polar bears prefer that you fix all emissions issues and run engines with the needed parts to allow for them to adjust the fuel delivery and in the end be more efficient that just running them without these parts.

[pushkick]

thats a nice thought but the question was trying to find out how do you know by the running of your engine if the o2 sensor is working or and the cat is blown or worn out. some of the experts on here must have analyzed the effects of each one of these items separately or when both have failed.
how would the engine run if the o2 sensor is not workling?
how would the engine run if the cat was not working?
how would the engine run if the cat and o2 was not working?

i was trying to get an idea by engine running (or response)what the device was not working?
_________________
i see said the blind man to his deaf dog
i am going to quit smoking and drinking and die a healthy man. gotta laugh
there is no deed to the planet earth
1990 vw automatic camper

[insyncro]

A DigiTool or multimeter will help answer those questions.
Refer to Bentley for testing procedures and numbers you are looking for.

[vanagonjon]

Why are you asking this question?

[hdenter]

It depends on what is wrong with those devices how the engine will run. If the O2 is just disconnected then the car will run in open loop just as it does when you start it up cold. It will drive fairly well and give so so fuel economy and performance. If it is damaged such that it is grounded or the signal wire is grounded, then you will get very bad fuel economy and run rich.

If the cat is clogged then the car will be sluggish and perform badly. If the cat is broken up, then the car will run just fine, but the environment will pay. When the cat is working well your hand should feel a noticeable "pulse" if you put it close to the exhaust at idle. Sort of like putting your hand in front of your face and repeatedly making the "P" sound. If it feels more like a steady flow and there is no quiet "pop" with each pulse , then the cat might be clogging up. Also, when the cat is working well, once the engine is warmed up it should be a bit hotter than the exhaust pipe going into it. Aim a hand held temp sensor at the inlet header about six inches before the cat and take a reading. Then, aim it at the cat and record that. If the cat is burning up extra fuel in the exhaust, it should be a bit hotter.

Of course, there are many other problems that can manifest themselves with poor performance and rich fuel mixture. The temp2 sensor is the first that comes to mind. Good Luck!

Hans
_________________
'79 triple white convertible bug
'84 sunroof vanagon
'85 weekender

[pushkick]

the reason i am posting these question i am trying to understand the how to trouble shoot exhaust problems and a running problem. i wanted to get a understanding of the what to expect when a part of the system was bad or going bad. so from what hans posted if the cat is blown out or no screen left then if the o2 sensor is working then the engine should run fine and gas economy will be ok. if the o2 sensor is shorted to ground then the i should see very lower fuel economy and black carbon build up on tail pipe exhaust and poor performance. if the o2 sensor is just open circuited then i should see a lower fuel economy. so a grounded wire or broken wire on the o2 sensor could be a major problem. i know that you can look at the signal from the o2 sensor with an oscilliscope and i know it should look like a sawtooth wave form once it is heated up. i know how to test for a grounded wire and open wire. is there any info on the parameters of the o2 signal and when is and where it is out of spec indicating that the sensor is failing? what happens to the o2 sensor signal when the cat opens up or when it is clogged?

so when the cat is starting to fail and it breaks up and creates a blockage the engine should be sluggish and have poor performance. if it opens up and the engine should run fine. so the only way to tell if cat is bad is checking the exhaust or looking into cat itself to inspect.

thnks han that explanation really helps and lets me understand the cause and effect of each part and where to start looking.
_________________
i see said the blind man to his deaf dog
i am going to quit smoking and drinking and die a healthy man. gotta laugh
there is no deed to the planet earth
1990 vw automatic camper