Exhaust Question

[abvgrndsub]

I need to replace my cat. and muffler on my 90 Suburban. My question is can I just replace the muffler and add the extra pipe or will the computer know theres no cat and give me problems? I dont have to smog my truck for a year so I dont want to put the cat till next spring. Could this cause any problems?

 

[southernspeed]

You should be fine. It MAY run a bit lean. Just use Winaldl to check your BLM's. If they're all around 128 or below you'll be ok.
I run mine like that at the moment and need to burn a chip as it's a bit on the lean side but I'm sure that has more to do with the motor build than the exhaust. Plus I'm running a straight through Borla 3" sportsman muffler.

 

[Thunder]

It will run fine without a cat. The ECM of OBD 1 cars and trucks does not look for catalitic convertor operation like later obd2 does.
I run my 89 TBI with a muffler where the cat used to be and a dump right after the muff.