Specs on exhaust backpressure? Catalytic Converter?

[ssjerry]

i think maybe the catalytic converter is plugged up or bad on a 1991 GP with 3.1 engine. what is the allowable backpressure for the exhaust system? if someone has had one plugged before and fixed by replacing, what were the symptoms?

i've got a pressure gage plumbed into the egr fitting on manifold and just realized i don't know what it should be.

 

thanx.

[Robby1870]

symptoms include severe lack of power, rough idling. Shake the converter with your hand and see if it rattles. If it rattles, get a new one

 

Robby

[Lee]

in the case of my 91 regal it was aplugged up stock muffler.

[Slade901]

0 to 3 psi good

3 to 6 psi moderate restriction and loss of power

6 and higher major restriction and loss of power

 

That's the PSI difference between pre-catalytic and after catalytic. Remember: Don't drill directly on the components themselves. Don't dril on the exhaust manifold, catalytic converter, muffler, etc., but only drill the exhaust pipes themselves.