friend has a 2000 prelude and just bought a high flow cat converter to go with his exhaust.

the car runs bad now with the high flow cat on and with the stock O2 sensor.

the car ran good with the stock O2 sensor and stock cat. he took it to autozone and had them check it out. they said that there is another sensor to get for high flow cats to make the O2 sensor read correctly??? i never heard of that.

basically with the new cat on, the car is adding more fuel and it runs rich and runs poorly.

i say add a new O2 sensor. would that fix this weird problem?? any advice is appreciated. Thanks guys

 

anyone know whats up?

 

which O2 sensor are you talking about? 1996+ -> OBD2 -> 2 O2 sensors
and how do you go about adding another O2 sensor? 2 should be enough...

anyways...what CEL are you getting?

 

Well it being a 2000 prelude it is obd2 = 2 O2 sensors.

Is the high flow cat he bought a real high flow cat or is it one of those fake ebay cat's?

 

well not sure on the cat, i will ask him today.

as far as CEL, he took it to auto zone and they said the O2 sensor isnt reading correctly because of the highflow cat, and causing the car to run rich and spray gas out the exhaust.
they told him there is a sensor that works with the O2 sensor to make it read correctly. i never heard of that before..

my advice to him is to replace the O2 sensor, but he says the car runs fine with stock cat and stock sensor. its just when he adds the high flow cat, thats when it runs bad.

thanks again for helping me out

 

its probably just a resonated test pipe, not an actual cat. If thats the case hes going to throw the secondary O2 sensor code or the dead cat code. He needs to get an O2 simulator or get a REAL high flow cat from a muffler shop.

 

yep, he bought it off of ebay motors and i suppose it aint a real cat. LOL

so he found this sensor thing. is this what he needs to get it reading correctly?
https://www.casperselectronics..._Code=

 

I had the same problem with my race cat. I did the mechanical O2 simulator mod for about $5. I haven't thrown a CEL since. Just make sure the car isn't running too lean. Here's the link http://www.s2ki.com/forums/ind...29959

 

Except for the Casper's, you should actually get this one based on the part numbers and car applications, not the one in the link .........

Part # 104053

 

thanks for the help...

i will let him know