P1133 O2 error question PROBLEM FOUND!!

[nivit0]

My car threw an error code that Autozone scanned and found to be P1133 Heated Oxygen Sensor (HO2S) insufficient switching bank 1 sensor 1 (Rear Bank). I do hear a whistling sound like there's an exhaust leak. I expect this problem to be related to the exhaust leak, but it could be the sensor too. I had a new muffler put in, and the shop couldn't find the leak in the system when checking under the car. The guy said it might be at the exhaust manifolds. I need to know two things:

Where is this sensor located; Bank 1 Sensor 1?
Where is the most likely place for an exhaust leak to come from? (Where manifold meets head, at y-pipe, etc?)

If it is at the manifold/head surface, how much is an exhaust manifold gasket, and is that something I can do myself in the driveway?

[ November 23, 2004, 09:50 PM: Message edited by: nivit0 ]

[Turbo V6 Camaro]

i think bank one sensor one is the one in the driver side header

[OneQuickV6]

Driver's side manifold/header is where it's located. Alot of times, this code is throw by a leak. You might listen for it from under the car or abvove the engine bay real close. Common issues with some exhaust manifold gaskets is blowing. You normally will hear a loud ticking sound if this is the case.

[Turbo V6 Camaro]

check the EGR tube too

[nivit0]

I'm going to assume it's an exhaust manifold gasket based on what I'm hearing. I've found a listing for the gasket on the autozone website for ~ $18. Is that the price for one or two?

When you said check the EGR tube, I imagine you mean check it for pressure leaks, not for carbon build-up. It is filthy inside that tube, should I spray it down with some carb/throttle body cleaner, or would that not even matter?

[nivit0]

Alright, I called one of my local shops, they want $140 to change the driver's side exhaust manifold gasket. That won't happen. I asked one of my friends to help me with it, and he brought up a good point. If it was the gasket there, the sound I hear should be choppy. I get a constant exhaust tone from the leak, making me think it might be further downstream than the mating surface with the engine head. From what I've read, for the O2 sensor to throw this code, the leak must occur upstream of the sensor. I haven't yet checked the EGR tube, and I do plan on doing that later today, but is there anything else I should look for? Can an exhaust manifold gasket leak cause an even tone sound?

[Turbo V6 Camaro]

Originally posted by nivit0:
Alright, I called one of my local shops, they want $140 to change the driver's side exhaust manifold gasket. That won't happen. I asked one of my friends to help me with it, and he brought up a good point. If it was the gasket there, the sound I hear should be choppy. I get a constant exhaust tone from the leak, making me think it might be further downstream than the mating surface with the engine head. From what I've read, for the O2 sensor to throw this code, the leak must occur upstream of the sensor. I haven't yet checked the EGR tube, and I do plan on doing that later today, but is there anything else I should look for? Can an exhaust manifold gasket leak cause an even tone sound?

any leak around the gasket i have ever heard was a ticking noise not constant like your doing

[nivit0]

Alright, I've found the problem. The leak is where the driver's side exhaust manifold meets the y-pipe. The 'donut' that's supposed to seal the mating surfaces is easy to wiggle by touch, and it would appear that I'm missing a nut on one of the two flange bolts. I can't even say for sure it happened when I had that transmission work two weeks ago and they had to lift the engine. That nut may have been missing for a long time. I will now get a new exhaust donut, and try to find a replacement nut. Anyone know what threading it would be? 1/4-20 is my guess, but I'll find out Sunday when I work on it. Once I get this all sealed up, I'm definitely running a can of seafoam to clear up the extra unburnt hydrocarbons. The car has been running pig-rich for weeks, mileage has been krap, it was spraying extra fuel like crazy.

[Wicked 3800 V6]

Look in the car parts manual, it says the pitch of each bolt. Then go to Home depot and get one from there.

The bolts are $3 from the dealer, and honestly, that's a good deal, considering you get the exact bolt you need.

-Rob