emission testing

[TC]

1990 probably has only one O2 sensor.

The cat should be right after the Y pipe, if you can fit it that far forward.

Ya if the factory Y-pipe is still there then where ever the new pipe starts is probably were the cat was..........

[A/Fuel]

The O2 sensor is in the y pipe, so I'm just going to cut the pipe and attach it right to the Y pipe.
Cool, thanks....Hopefully this will be it, I'm getting tired of screwing around with this thing.

[milner351]

TC - your camaro is new enough to have "light off" cats - close to the engine, then one or two more under floor - the trucks were in a different emissions class that didn't require the extra cats until much later.

A/Fuel - get the cat as close to the Y in the pipe as practical - behind the O2 sensor and all should be well - sure hope that solves the issue for you.

[Beagle]

Speedway Motors - I just bought two new 2.5" cats for 44.00 each. You will get them in about three days. I'm guessing after the Y it's not bigger than 2.5, probably a 2.25? 50 bucks should get you going.

My car had four originally, they put two right after the shorties. I'm betting two will pass with the 460 even. With the cats moved back some (about a foot) on my F150 a few years ago, for long tubes, it passed. Dallas / Fort Worth has about the strictest standards I know of short of LA. It had no problems passing.

A 1990 just about any brand truck would have had one cat behind the y-pipe, right after the y, probably within 6 inches of it going to the Y. The closer the better has been what I have always heard, but mine were back a ways and still passed easily. The O2 was in an H about 4 inches before it "Y"'d.

An oil change and hot motor really help. I let them change the oil with a bit of an understanding - pass the damn truck. The worst I had to do was put mufflers on the Lightning because they couldn't get a reading (rusted completely through at the muffler entrance).
A new 02 sensor can't help but make it run better on a truck that age, IMHO.
Check with Speedway would be my input to this after I see myself repeating myself repeating stuff.

[A/Fuel]

I already bought one, $92, I whish I would have known...Oh well.
I got pulled over the other day in some little hick town in Indiana at 3:00am. My 30 day permit had expired, I had a whole stack of papers, recipts, emission test results and just kept talking until he agreeded to let me go, lol.
He was following me for about 20 miles, I could tell he was running my plate. He would get right on my bumper, then hang back for a bit, then back on my bumper and so on. One time while he was about 6 feet off my bumper I looked out the windshield and seen a dead deer lying on the road and swearved pretty hard, he didn't and plowed right over it. LOL, after he agreed to let me go I said I knew you were running my plate "I should have just pulled over" He said yeah, it would have been easier and I wouldn't have hit that deer.....LOL Drive safe..

[anotheridiot]

I just asked the year and make of the truck to see if I could find a diagram. So far I just got 1990, so dont know the rest.

Walker has pretty good information out there. When I order from Rock Auto, they usually have all the exhaust parts on a diagram that were on that thing stock so you can see what they did or what they removed.

[TC]

TC - your camaro is new enough to have "light off" cats - close to the engine, then one or two more under floor -

My camaro just had two Cats, one off each exhaust manifold, there were no Cats under the floor...........

[A/Fuel]

It's a 1990 chevy 1500, 4.3 5-speed....
One last question before I put this on, it doesn't say anywhere on it inlet or outlet or have any arrows anywhere. It has a little pitot tube comming off of it that looks like it's for a hanger. Does it matter what direction it goes?
Here's a pic.

[Beagle]

tubing would point towards the radiator on mine , smog pump puts air in there.

[anotheridiot]

yeah, before you put it in make sure you have an air tube down there. if that was removed with the smog pump you will probably need one without the fitting.

[anotheridiot]

then this is the page for rock auto for that exhaust with walker

http://www.rockauto.com/info/Walker/DetailFrame.html?www.rockauto.com/info/Walker/1031162-18255.html

the air pipe would be on there, I know thats where I ordered the new one for the 1990 jeep.

[A/Fuel]

yeah, before you put it in make sure you have an air tube down there. if that was removed with the smog pump you will probably need one without the fitting.

The smog pump is still on and has all the tubes in the exhaust manifold. I was just looking at it and I can't find any hoses or tubes that go down there, or anything that looks like it was removed or capped off.

[squirrel]

If there isn't a tube to connect to it, then you probably just have to cap or plug it. With a heat resistant cap or plug, of course.

[A/Fuel]

The tube from the converter already has a cap. I think I'm just going to put it on and hopfully go get it tested.

[squirrel]

sounds like a plan. Get it warmed up good before the test, like drive it for 15 minutes, and don't wait around long before the test. Heat is good.