From o2 sensor to engine replacement in 10 days?

I've been following the thread with interest, but did not want to add to the already busy stream of data. Until now.

You asked about an easy to use jack so you can feel safe under the car. This is really, REALLY important. NEVER ever climb under the car that is supported by jack alone. That is a big no-no. Buy yourself a pair of jack stands at your local auto parts store, lift the car with a jack and lower it onto a jack stand placed at the appropriate support point under the car (location of such points can be googled). Only after the car is resting on jack stands securely should you attempt to climb under the car. In fact, once jack stand securely support the car, it is very safe.

Presently, I would definitely climb under the car with a good light source and have a look see at the whole muffler/cat/O2 situation. It may be very obvious once you are under there. A loose O2 sensor, a leaky connection between pipes, etc. can contribute to the problems you are having. It sounds like the problems started after the dealer installed the upstream O2 sensor. I would start my investigation there. Downstream O2 sensor was next to be installed by the very suspect dealer. Inspect that next. Get the friend that installed the cat for you to come over and inspect his work. I am pretty certain your problem lurks in that area of the exhaust system.

Good for you to learn to be independent of dealers and car mechanics. I have done so since I was 16 (many years ago) and realized that the only way to do things right on the car is to do them myself or at least to understand really well what exactly needs to be done in case the job is beyond my abilities. It's a good way to own a car. I've been maintaining a repairing my own cars since 1981.

 

Lol I should've asked if the loud noise was coming from the front or rear. We've been chasing the muffler noises lol

@theelectricme, here we come 250

 

There is a gasket that is quite close to the 'engine' area (front exhaust pipe assembly), and not far from your right foot when sitting in the drivers seat.

Here is an image that might help :

 

I don't accept the dead engine diagnosis, they don't die like that.

That advocate was horrible, maybe you should try again with another one tomorrow

 

Just piecing a few bits together...

So the loud sound is coming from the front?

You also referenced finding something underhood that looked dark and wet, but turned out to be dry? Possibly carbon and ash around a leaking exhaust flange?

 

From the Techstream screen for the P0A0F code (post 226), the subcode is 204.

Research the troubleshooting for that and see what you get.

 

Alternately now armed with these codes, I’d pay the $20 for 2 days at tech info and use the repair manual.

 

@SFO

 

Here is the workup for DTC P0A0F with a detail code (aka subcode or INF) of 204, 205, 533, 534

https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8CPDF%E6%A0%BC%E5%BC%8F/Prius%20Service%20Manuals%202004/%E4%BF%AE%E7%90%86%E6%89%8B%E5%86%8C/04pruisr/05/21bpm/0a0f204.pdf

and for DTCs P0136, P0137, P0138 :

https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8CPDF%E6%A0%BC%E5%BC%8F/Prius%20Service%20Manuals%202004/%E4%BF%AE%E7%90%86%E6%89%8B%E5%86%8C/04pruisr/05/2054m/cip0136.pdf

and for DTCs P3190, P3191, P3193 :

https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8CPDF%E6%A0%BC%E5%BC%8F/Prius%20Service%20Manuals%202004/%E4%BF%AE%E7%90%86%E6%89%8B%E5%86%8C/04pruisr/05/2054m/cip3190a.pdf

 

Next stop....300!

 

I think you really need to focus on the P0137 code. The malfunctioning O2 sensor could be the cause of the poor engine performance. It's the one thing your car is telling you is not working right.

Starting on page 05-137 of the link from SFO are some simple and clear tests for the O2 sensor.

 

nah scratch my idea. If that was on the front of the engine, then it couldn't have been the exhaust. As far as I know the exhaust is on the backside of the block of every version of prius.

Doesn't mean the sound isn't an exhaust leak, just that it isn't the same thing you didn't quite have in that earlier picture.

I'd say go back to working on the excellent suggestions in #255, that's something very direct and important.

 

Thanks for updating this thread with the outcome of your test drive. It is disheartening to see that your engine still has problems. I reviewed the screens that you posted in 226 and did not see anything that would be particularly helpful.

It is very interesting to see that no engine misfire DTC is logged.

I see that a helpful forum member, SFO, provided links to the relevant portions of the manual. Regarding DTC P3190, here is a full list of the possible issues per the repair manual along with my commentary:

Air induction system - you tightened the clamp holding the air cleaner housing to the throttle body and were looking out for leaks downstream from the MAF sensor, right?
Throttle body - you cleaned that
Fuel pressure - we don't know how this is doing
Engine - we don't know about this yet
Mass Air flow meter - you cleaned that
Out of fuel - I believe you said the vehicle has adequate fuel
Engine coolant temperature sensor - the screens you provided show the coolant temp was 82 degrees C and started at 1.8 degrees C, which seem normal (if the ambient air temp is near freezing)
Crankshaft position sensor - don't know for sure, however if the engine ran for 10 minutes prior to registering the warning lights, I would be inclined to say it is probably OK
Camshaft position sensor - same as crankshaft position sensor
ECM - same as crankshaft position sensor

If this were my car I would check cylinder compression, to verify the pistons and valves are working correctly. 128 psi is the standard, the minimum allowable is 99 psi, and the difference between cylinders should not exceed 14 psi. Then I would measure fuel pressure which should be 44 - 50 psi.

 

Well, none of the logged DTC that you reported point at the upstream air/fuel ratio sensor. However since you've been complaining about the engine making excessive noise, it wouldn't hurt to inspect the exhaust manifold, exhaust pipe, etc. at the same time that your mechanic replaces the A/F ratio sensor.

I would not expect the downstream oxygen sensor to negatively impact engine performance because all it does it report to the engine ECU the health of the catalytic converter.