Am I drunk to think this can be done? Anyone versed enough to know where the O2 sensors are positioned in the exit only plumbing?

 

It's technically possible but the car will not pass emissions tests and in many countries it is illegal.

 

Nor is there any benefit.

 

Game on, I think Alberta is one of the last places to care about emissions
Apart from no benefits gained, what are the odds that the cats are plugged at 128,000km? I get all sorts of header leak noise on start up, with an approx 4-5 second delay on exhaust from exiting the tail pipe...

 

That's not high mileage (km-age?). If they're plugged something else has been badly wrong to cause it. Get a decent OBD tool and look at the O2 waveforms, check for codes, fuel trims, etc. Whatever has been wrong probably is still wrong and needs fixing. Apart from risk of severe engine damage you're probably down on power. What's your fuel economy like?

There are plenty of previous posts about this, as well as some O2 sensor data I posted.

 

if the cats were plugged youde have a check engine light and it would run like crap. yes you GUT the cat, installed anitfoulers in the downstream 02's to space them out of the pipe to keep the CEL off. But it will be louder and the exhaust smells alot afterwards.

 

Stop tempting him LOL

 

It was a long shot, thought I'd inquire if it was a potential cause! No CEL symptoms, no real loss in power, fuel economy is at 360km a tank...

 

That sounds very low fuel economy but depends what you call "a tank"

(I get more on my STR!)

 

I had my cat deleted in my '96 FWB but I get some codes since then , you would face the same as well .

 

get spark plug anti oil foulers with the same thread size as the 02's and take out the downstream 02's. Screw in the foulers then screw the 02's into the back of the foulers. This spaces them out usually enough to get them to think the cats are cleaning the stream

 

I'm thinking it won't run closed loop - right? And will run a bit rich? Or is it fooled?

 

Thank you for the tip ,this is why it's crucial to have such tech friends like you

 

You can get dummy O2 sensors also. Pretty common on other performance cars. I don't know if you would need a specfic one for a Jaguar or not. Take a look here. Also known as a "O2 Sensor simulator"


http://www.o2simulator.com/?gclid=CI...FRCdnAod3Hp7oA
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My thoughts exactly, we replaced the cat on a Ford 6L diesel for the same sounding symptoms, exhaust manifold leak cyclically, and considering a full tank (app 7/8 used) is yielding truck like mileage... Fuel and air filter are done, fresh coils and plugs this summer (all 8), no codes to be read, noted exhaust exit delay on start up (4-5 seconds before seeing tailpipe exit (cold Calgary))

The O2 fooler puts thing into perspective, and after it was explained that the OBD2 reader can plot the voltage and frequency of the current setup, we should be able to figure out if they are actually functioning properly before chop/cut/reweld

 

The (2002) facelift cars have wide-range sensors upstream. The earlier cars probably do too but I'm uncertain.

Wide-range don't switch frequently. Most articles on the net assume the older type of O2s. They're used downstream, and shouldn't switch much if your cats are OK (especially if the fuelling's good). You want fuel trims to be no more than about 10% (pref. 5%) on each bank (add short+long trims) when running CL (closed loop).

Blipping the throttle or causing an air leak should make the upstreams flick - and rapidly - if they're OK.

O2s (especially the upstream) live in a hideous environment so can degrade, get poisoned (bad oil etc) or break.

edit: the original cars (1999-2002.5MY) do not have wide-band (aka linear aka AFR) O2 sensors

 

Bringing this back from the dead...TBird, this site is no longer accepting new orders...Anyone know where to find the correct simulator?

Thinking about doing a cat delete as I'm hearing it's somewhat common for the cats to clog...

What are the laws? I know it's generally illegal, state enforced...Is it legal for an exhaust shop to fab up bypass pipes, test it in the shop for leaks, remove the bypass pipes, put the Cats back on with the bypass pipes in my trunk, I leave and install the bypass pipes in my driveway?

 

Not sure what your getting at?? If the remove the cat how are they going to reinstall it?? With the bypass pipe in place where does the cat go??
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Edited my last post...