I have some question fellas. I recently purchased a 1998 Blazer 2WD w/ 171000 miles on the odometer. It seems to be running okay but when I got the truck home I noticed the absence of a catalytic converter. At first I thought no big deal. I'll just put a new one on and be done with it (Missouri requires a cat). Well then I started to think about it a bit more especially when I also noticed there had never been a CEL light indicating an emissions problem.

Fast forward a few days later and this morning I decide to have a cat put on the truck. No I didn't have an OEM put back on it (I don't have 300.00 right now to spend) but instead one of those Magna Flow catalytic converters. The shop warned me but I told them I have had no light indicating any problems since I've purchased the vehicle.

Now I've only driven it about 29 miles with the new converter but I drove it for about 100 miles before I had one put on the truck. I am still not getting a check engine light. Could the previous owner have done something to the emissions system to bypass a check engine light? I've read about spark plug spacers but I didn't nor did the shop see any O2 spacer on the exhaust system.
sensors.

 

Does your engine light come on at all? turn the key to "on" if it doesnt light up,either they pulled the bulb or its blown.

 

Yes, the light comes on temporarily. Then it goes off after a couple of seconds. Just like it should.

One thing the shop guy said was that it may take 150 miles or so before the light it tripped. Does the computer take awhile to sense a change in the emissions system?

 

Yeah the person could have reset the computer before they sold it to you and you might not have completed the drive cycle yet.

 

I'm pretty sure the older 2nd gen blazers (95-97) won't set a CEL without a cat although it will set a trouble code. Check with a scanner and you'll probably have an emmissions code stored. I've been running without one for almost a year in my '96 and I've set a code but never a CEL. The newer blazers (98+) will light the CEL if there's any problems with the cat though.

 

On my 2000 Blazer I got recently it had the cat removed and there appears to be a 2 spacers on the rear O2 sensor and I haven't had any CEL lights for the 2500 miles I've driven it. The CEL isn't burnt out and the truck runs great too.

 

Dadatone, I think you've already gone the best route by replacing the Cat. Even if there isn't emissions checks in your area you're better off with a Cat since it's OEM equipment and you're helping to reduce the emissions from your truck. A decent aftermarket one like you got won't have any performance hits so it's a win-win. I'd say you'll likely not have any problems with the aftermarket Cat.