What Happens If ?

[LEE.W.]

Can anybody shed some light as to an exhaust exchange i want to do.

I want to remove my rotten old standard exhaust which would mean removing
the cat and the rest of system towards the rear of the car.To be replaced with a stainless system and motorcycle end can.(I shall make all this)

My questions are about what happens to the fuelling by removing the cat and lamda sensor,and would i have to plumb in the lamda sensor back in to the new system.

Are there any mods to ECU needed.

I am concerned about wrecking a perfectly good engine and still not getting my 50mpg.The car is standard condition at this time and just recently the red cat light stays on now permanently. Lee

[Wh1teLeopard]

I'm not sure on the exact details, I think Steve should know, but you do have to do something with them as like you said it will confuse the ecu making it not run properly.

I know other Honda's have the same issue, you can buy replacement sensors for them that trick the ecu I think, but I doubt they'd fit the beat anyway.

[Midship]

I wouldn’t bother.. keep the cat

I butchered mine and had to get a replacement. The O2 sensor gets messed up and sends incorrect signals to the ECU, ECU over fuels, bad news for valves.

Not worth the trouble

[Steve_M]

Keep the cat, the O2 sensor wont be able to sense the exhaust gases properly with out it as it needs the cat back pressure to allow the gasses to hang around a bit. This will cause problems with fueling.

Best just to build new exhaust system that mates onto the cat joint, Your planned exhaust sound noisy!!!

Cat heat sensor light has no effect on engine running if its on/sensor fails. you could just remove the dashlight bulb. Its a Japanese regulation, later cars now use secondary O2 sensor to check Cat operation.

HTH

[LEE.W.]

Then it sounds like i will keep the CAT and graft my new system onto its joint.
This will be a side exit Remus grand prix oval system exiting from either the left or right side of bumper.
Many thanks to all of the above as your advise is invaluable.