Help with oxygen sensors?

If you have an inline engine, you only have bank #1. V4, V6 & V8 engines usually (but not always) have Bank #1 (left side, driver's side) and bank #2 (passenger side) of the exhaust system. It's also possible that V engines will have a single exhaust, therefore, only a single upstream and downstream O2 sensor. Whether you have a single exhaust or dual exhaust, the upstream sensor will be the same part number regardless if it is bank 1 or bank 2. Same for the downstream sensors (different part #, but the same part # for both banks).

If you are asking where the O2 sensors are located on your exhaust system, just follow the exhaust pipe along its length. You'll find both of them somewhere along the pipe. They measure the efficiency of the catalytic converter, nothing to do with the muffler.

Upstream is on the inlet end of the catalytic converter that is toward the engine. This may be immediately before the catalytic converter or closer to the exhaust manifold. This is sensor #1.

Downstream is on the outlet end of the catalytic converter that is connected to the muffler. This is sensor #2.

Get a 2nd opinion on the evap canister especially if someone says you need one and they didn't get an OBDII code.. An OBDII tester should post a code if there's a problem with the evap system.

Hi the issue here is about emmissions and new laws. the first box inthe chain is the catalytic converter which is supposed to burn off al the worst of the toxic gases this has oxygen sensors fitted so the engine management system gets some details of how wel the engine is burning the fuel. the others down the chain of te exhaust also monitor the gas flow and give back details on how to adjust the injector samples.

the technicallity is all part of giving you the motorist the most economical MPG. so yes they serve a very good purpose. yes i know what you where asking rick hence my answer. the engine management system does it's best however as the car gets to be as old as yours is it may need a new cataylitic converter before too much longer as the do clogg up hence the issues you have been having.

Next time please post the OBDII codes for us. I have had good luck with Ford OBDII codes pointing out the faulty oxygen sensor. Some people try cleaning the O2 sensors but if I'm going to the trouble of removing the sensor, I'm going to install a new part.

COULD IT BE A GROUP THING ?

For correct sensor part number and location, you must read and record your calibration.

Contact Ford parts. provide your vehicle info.

They can tell you the sensors and locations your vehicle was equipped with.

Terminology can be corrected that way.

Confusion can be erraticated and your correct answer

can be known in a few minutes.

Their part will be the current attempt by the engineer to perform the task when you use the fuel that is available for sale to you, and you provide the correct diagnosis.

A technician is supposed to be able to help, but even he must question current parts and TSB as well as possible emission recall info.

It has to be this way because this information has to be kept updated. The dealer pays people to keep it correct, updated, and available.

You could also correct them if a TSB or recall is more current and correct, and it applies to your vehicle and diagnosis.

The aftermarket has these scanners available to point you to the parts in question, the pin point test helps decide if the part is a failed part or not.

Often, these sensors MUST be replaced in a group because of potential repeat repairs, and the (causal condition) occurring.

So, dont hate the truck, question the diagnosis and the available fuel, then question and obtain the most current info, please.

You want to tell us the codes or keep playing guessing games? You didn't even say if it was a 4 or 6 cylinder motor. Even when you get the codes you still need to monitor the voltages and switching times to verify it really was a bad 02 sensor that is causing your run-ability problem. Upstream means before the converter (between the motor and converter. Downstream means after the converter.

I would just replace both. When one goes, it usually means the other is going to go soon. Also, just a bit of advice: Never start the engine with the oxygen sensors removed. If you do, the check engine light may come on and stay on until you bring the vehicle to a Ford dealer to have it reset.

Sensor 1 is upstream ahead of the catalytic converter. Sensor 2 is downstream AFTER the catalytic convter

DONT BOTHER WITH IT JUST YET! The reason for most O2 sensor issues is a dirty CONTROL VALVE! A new one will also act up if the IAC valve is dirty inside it! It adds more AIR as required from the signals given off by the 02 sensor itself! run GUMOUT through the IAC valve FIRST and then see what happens!

If a code is set for a O2 sensor it should be replaced. The upstream sensor is in FRONT of the catalytic converter, the downstream sensor is AFTER the converter.

the O2 sessors are not by the muffler they are neer the catalitic converter. bank 1 sensor 2 sounds like the downstreem O2 sensor but if one is bad and you have the money I would just replace them all. The evap will have little to do with performance that is most likley your O2 issue. Evap has to do purely with MPG