exhaust, and oxygen sensors

[brancart1]

I have a 91' SHO, MTX, and there is a hole in the exhaust, im thinking its where the exhaust manifold and the cats meet, well anyways, my car failed emissions and we are thinking it is because of the cats. My question is that if i leave the exhaust the way it is for too long wouldnt the oxygen sensors mess up the computer, and pretty much cause a snowball affect on my car. If anyone know anything about this problem then i would really need to know. ALso if anyone has a really good condition hi-flow-ypipe that i could buy then that would be great also. thanks
Brandon

 

[Blue-By-U]

Welcome aboard. Which part of emissions did you fail?

Check out these sites for some valuable information:

www.shotimes.com
www.shoclub.com
www.shonutperformance.com
www.midwestsho.com
www.fordpartsnetwork.com
www.spmotorsports.com
www.shoshop.com

 

[brancart1]

um i cant remember which part it was, i took the emissions test last year and i have to get it to pass before the end of feb.

 

[sdpatt]

An exhaust leak, unless massive and upstream of the O2 sensors, will not affect the measured emission output from the tailpipe and will not change the oxygen measurements by the O2 sensors. Your exhaust leak is likely from a worn out donut gasket at the ****** downstream of the cats. The Fel-Pro 60641 gasket can be had from O'Reilly or most auto parts stores for about $5.29. You will need an 18mm socket to remove the two, spring loaded bolts on the ****** where the two cat pipes merge.

You may want to read this link regarding the possible causes of excessive emissions generation. It could be anything from old and slow switching oxygen sensors to vacuum leaks or spark plugs with too large a gap. Our non-EGR engines are having a more difficult time passing the increasingly restrictive emission tests.

A last resort, if you are able to pass the HC measures and are slightly over on the NOx component, is to remove the SPOUT plug prior to driving into the shop for the test. This plug is located nead the CID sensor at the passenger side of the rear cylinder bank. This will reduce the power of the engine and the HC emissions. After getting the certificate and leaving the shop's premises, reinstall the SPOUT plug and enjoy the SHO.

 

[brancart1]

Thanks