Exhaust Q\'s - Lamda and Temp Sensor

[najiru]

I\'m in the process of replacing my cat and upgrading the downpipe and have a couple of questions. My PFC shows that the lamda has died but does the PFC use it? Just it would be easier to change whilst I\'m messing with the downpipe but if it\'s not used then I\'ll just swap the old one in to plug the hole.
 
Also I have removed what I assume is an exhaust temp sensor from the cat but the decat has no place to re-install it. What is the impact if I leave it out/what is it for?
 
Cheers

[pdtaylor18]

You will still need the lambda but you can do away with that other temp sensor if you are doing away with the CAT.

[najiru]

Thanks Pete, I\'m replacing with a decat so i\'ll just get rid of the temp sensor and replace the lamda.
 
Thanks for the help

[trotter]

Why do you need the lambda? I thought it just let the ECU know how much O2 was in the exhaust gases??? Is it used to compensate for running too rich/lean?

[nikp]

You can tell the PFC not to use lambda, and therefore make it unnecassary. The wire has come off the standard lambda sensor on mine, but it makes no difference as it\'s turned off.

[najiru]

Ah ok, can you turn that off from the commander? I\'ll be getting it mapped after I\'ve got parts fitted so i can just get it done then if not.

[pdtaylor18]

With no Lambda or a faulty one it produces an unchanging signal or no signal at all. When this happens the engine may experience drivability problems caused by an overly rich fuel condition. Poor fuel economy, elevated CO and HC emissions, poor idle, and/or hesitation during acceleration are typical complaints. It is just feedback to the ECU but it still uses this information to change the air/fuel mixture.
I suppose with a PFC you can frig all the data to get through the MOT but if this is just a track or drag car then yes you can block it out.

[DR SCHNITZEL]

hmmm this is interesting information. Is it then possible to run the wideband sensor in the downpipe location for a few hour mapping session? Or is it too hot in that location? I have been wondering about this lately.

[AshRX]

the sensor will burn out more quickly in the downpipe.

Mine is plugged into the decat

[najiru]

Well with the cat and airpump gone the MOT is going to be an issue anyway, however if I\'m going to have engine fueling issues as a result then I\'ll replace the lambda. Slightly confused how nikp is running without one with no probs though?
 
Next question..... anyone know where I can get a cheap sensor to suit?

[pdtaylor18]

You can run any engine without a lambda sensor but its only there for the emissions side and not when you give it WOT. It may just help you go through the MOT.

[DR SCHNITZEL]

can you run the wideband in the o2 sensor port for mapping purposes.
 
I was also thinking of installing the wideband a few inches down th emidpipe, does anyone do this?

[AshRX]

midpipe is fine

[nikp]

Mine is in the mid pipe.

[DR SCHNITZEL]

great guys cheers