Rotornut

I just bought a 93 FD with the stock main cat on but the air pump is removed. The car failed the emission test miserably.

I heard that the stock main cat will not work right without the air pump.

Will I get better results if I get an aftermarket hi flow cat to replace the stock main cat?

Thanks for your response....

Sonny

I think your best bet would be to source a known-good stock cat and hook the air pump back up. All of the "good" (Pettit, Bonez) aftermarket cats that I've seen have an air pump hookup. Most of them cost $500+ if you buy a new one.

You can probably find a good OEM style one for less than $100 in the classifieds.

Sonny

rynberg

The cat is most likely toast, but in any case, you need an air pump hooked up to pass smog, no matter what cat you are using.

HeatTreated

Does the car have a DownPipe as well?

Rotornut

No downpipe. I still have the stock with pre-cat on. Thanks.

wrankin

basically, the cat needs air(O2) to burn off all that extra unburnt fuel in the exhaust. It gets this from the air pump. No pump, very little reduction in emissions.

You need to get that air pump back on. Then get emissions checked and then see if you need a new cat or not.

Sounds like the prev. owner may have had a mid-pipe on at some point in the past.

-b

Rotornut

Thanks Wrankin,

I on my way to the local specialist to re-install the air pump. I'll post the emission results once its done.