2003Silvyrado

I did most of this in the wrong order, made things alot more difficult.

Ok, I got the manifold heat shields off, then I unbolted the passenger side flange & exhaust manifold (and dipstick) and got the exhaust manifold out. Then I unbolted the y-pipe from the catback . Got 3 of the drivers side manifold bolts off, so that manifold is almost off too.

Got all 4 (why the fk are there 4?) o2 sensors off.

I still have to unbolt the drivers side flange so I can drop the y-pipe, and then get the headers maneuvered in and bolted up, and then screw the front o2 sensors into the headers.


I have a few questions though.
1. When I took off the drivers side rear o2 sensor, the damn thing was like welded on to its threads, a couple rows of threads are junk now with a couple rows left. Does this sound like normal? It will still screw back in but do I have to get a new one or what? I shouldve just unplugged them and left the rear sensors in the y-pipe, but it looked easier to unscrew them then unplug them (I couldn't figure out the plugs)

2. Is it ok to drive to an exhaust shop, I think its about ten miles, with just the headers and front o2 sensors on? (I need to get the y-pipe modified to fit these headers) What do I do with the rear o2s? Just let them hang there?

3. How much should I expect to pay to have an exhaust shop cut the y-pipe a little and weld on a couple new flanges, and then bolt that modified y-pipe in there?

4. Finally, whats the deal with o2 simulators? Whats the deal with aftermarket o2 sensors? What would you use either of these for?

What should I do? Should I just plug the front ones in, get to an exhaust shop, plug the rear ones back in and drive it like that? Or should I buy some fancier sensors or even simulators. I'm not real familiar with this stuff.

getchusum99

iTrader: (1)

instead of getting your factory ypipe modified, get the exhaust shop or a performance shop to build you a custom y pipe,itll help with balance and give you more hp. i got a quote for 250 , but if you dont have the money, then ya goota do what ya gotta do. it would be ok to drive with just the headers on with the o2 sensors in, i would get sims for the rear to , i think there like 80 a piece at thunderracing.com plus if you get a custom y pipe the , u can get the cats omitted, and then u would need sims and not the stock sensors.i dont have headers myself , im fixin to get me a new truck so ill getem then.but my friend did some hooker long tubes on his 02 T/A not to long ago, and he drove around with just headers and the front 02 sens for 2 days until he could get to the muff shop. just tryin to help.

Flyer

iTrader: (1)

Wow .. you made that WAY to hard on yourself. Here's what I did for my headers install. I cut the pipe in front of the cats about an inch, unplugged the o2 sensor, and pulled the manifolds out with the pipe still on them. I've done this twice, both times I think it cost me 45 bucks to get welded up.

You can drive with the headers open, but I would unplug the front o2 sensors while your doing this. If you don't it will run incredibly rich because of the fresh air hitting the o2 sensors and freaking them out. Just make sure you plug them back up after you get it all buttoned up.

If your Y pipe will hang there after you cut it without coming to close to the ground, I'd leave it in place, but if it sags, yank it out and carry it up there. You better have something big to put on those nuts where the exhaust clamps up, they were torqued at what seems like 200 ft/lbs from the factory. They are a 15mm nut, not a 9/16.

You don't need the o2 sims nless your gutting your cats or taking them out completely. If it's a stock engine, I wouldn't do it just yet. I would wait until you have some more mods. The factory Y-pipe is just fine. It is actually a very well made piece. It doesn't need to be remade, In fact, I plan on whacking the ends off and use those pipes for my true duals.

2003Silvyrado

I wish I could just cut it. I have to be stealthy though, or the parents will destroy me.

I figured they were all metric, crazy new vehicles. I can believe the Y-pipe was attached with 200 ft lbs. That bitch is on there good! And being the *** that I am, I have the catback unbolted and one manifold out. So the whole y-pipe is suspended there by one flange.

I hope with someone helpingh to hold the ratchet on there I can get two arms in there to turn the damn bolts.
How do you unplug the sensors? Do you have to break that blue locking plastic clip or does it come out?

Flyer

iTrader: (1)

THe blue clip is a pin that goes through the little tab. It keeps the locking part of the clip from coming up so it will release. It just pulls out, then pull up on the clip and it will pull apart.

I still say the only good way to do it is cutting the Y pipe just in front of the cats. If you need the stock manifolds back on ... you can always cut it where the muffler shop welds them and have the stock manifolds put back on and welded up in place.

2003Silvyrado

And it will run better with no o2 sensors while I drive it to the shop, than with o2 sensors near fresh air?


Thanks for all the help.