dexter_dennis

What are the symptoms for the Clogged Catalytic ? Anyone THanks.

xeroinfinity

see this link.........
http://www.automotiveforums.com/vbul...d.php?t=665490

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1999 Grand Am SS 3.4 OHV

lebky

hera are some: loss of power at high speeds, stalling after starting (that is if totally blocked), drop in engine vacuum as angine rpm increases. Yes fuel economy will be lower too. The best way to test it is warm up your engine. Put your GA in park, connect vacuum gauge at your intake manifold increase your rpm to 2500 RPM hold it for 30 sec, if durring that time your vacuum gauge shows dropping needle replace your CAT.

xeroinfinity

This test alone probly wont tell you 100% if you Cat is clogged.
A pyrometer or an Infrared pyrometer should also be used to measure the exhaust temp before and after the Cat , if the Cats clogged then temps before the Cat will be much higher.

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1999 Grand Am SS 3.4 OHV

dexter_dennis

Actually those are exactl the symptoms i have... Probably i should change it... Any ideas how much will it cost me ? For grand am GT1 2000 Thanks. I guess you can not change it yourself right ?

xeroinfinity

Dending on where you live, probly around $150-200 including labor.
They do have to be cut in the front and the flange is usually rusty and the bolts might need cut off too.

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1999 Grand Am SS 3.4 OHV

dexter_dennis

Hey Xero i found a CAt on ebay

http://cgi.ebay.ca/Pontiac-Grand-Am-...QQcmdZViewItem

Is it a good one and you think it will fit as is or i need some extra pipes ? Thanks

xeroinfinity

If it says it fits/works on a GA then it should, but I'd ask to be certain.

All that would need done is measure the length of the new Cat then cut that much out from the pipe removing the old Cat. This Cat might also be less restrictive then the stock one.
Be sure to order the proper pipe sixe too, might try and measure yours.
Your GT I should be around 2.25"-2.5" on the down pipe to the Cat.

That Magnaflo is what I hav on my SE 3"inlet 3" out, a nice Cat for the price

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1999 Grand Am SS 3.4 OHV

lebky

This test alone probly wont tell you 100% if you Cat is clogged.
A pyrometer or an Infrared pyrometer should also be used to measure the exhaust temp before and after the Cat , if the Cats clogged then temps before the Cat will be much higher.__________________
XI I think pyrometer test is more for CAT efficiency (how well it burns CO, HC and NOx) the temprature after the CAT should be at least 100 deg F more from the temperature of the inlet pipe to CAT.

but I see, you can do it also t the the way you said,. Also nothing will beat back pressure test: (remove O2 install pressure gauge instead) pressure should be around 1.75 psi and if it goes over 2.75 replace the CAT.

but it is time consuming.