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Could the problems and symptoms I am having with my Corolla be caused by a restricted or faulty catalytic converter?
I think it can also be the other way around. Those problems can cause a cat to go bad.

If your cat was plugged up, you would have lack of power at highway speeds, especially when trying to pass a truck or other slower vehicle and especially on a slight upwards grade (a slight hill). It would also cause your transmission to operate abnormally (at highway speeds).

Pulling the exhaust to inspect the cat is not a hard job. You'll be able to see right in to the front of the catalytic converter. You won't be able to see the back of the converter without a boroscope, though. You can shine a bright light into the O2 sensor bung hole and look for the light to pass through the catalysts media to the front of the cat. It will look like difused light if it is not plugged up. If it's plugged, you will see only a spec of light here and there through certain of the square holes in the honeycomb media, with most of the holes having no l ight coming through at all.

You can also put a shop vacuum cleaner in reverse and see how well air flows through the cat.

If the cat is not plugged up, it can still be inefficient, needing to be replaced. That's the case with my cat.
 

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Rookie Wrencher with 2008 Corolla
2008 Toyota Corolla
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Discussion Starter #42
I think it can also be the other way around. Those problems can cause a cat to go bad.

If your cat was plugged up, you would have lack of power at highway speeds, especially when trying to pass a truck or other slower vehicle and especially on a slight upwards grade (a slight hill). It would also cause your transmission to operate abnormally (at highway speeds).
Thanks for this John, I think I'll pull my catalytic converter and see what it looks like. With all the fuel/air I've been pumping through it It could have a problem.

I think I'll replace the A/F and the O2 sensor. This could be the source of my problem, but maybe the codes aren't showing up for it because I can't get enough run time due to flashing CEL?
 

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Only replace the A/F and O2 sensors if they are bad. If you do replace them, make darn sure to use the Denso brand.
 

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Rookie Wrencher with 2008 Corolla
2008 Toyota Corolla
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36 Posts
Discussion Starter #45
As I said before - your oil overfilling on its own and the stench of gas is pointing towards leaky injectors. They are flooding the cylinders with gas and diluting your oil. Get them tested.
Thanks for the input doctorbee

Swapped injector #3 with #1, reset codes, about 45 seconds before flashing CEL. 3 codes, P0300, 303, 304. No freeze data.

Swapped coil pacs #3 to #1 and #4 to #2, reset codes, about 45 seconds before flashing CEL. 3 codes, P0300, 303, 304. No freeze data.
I thought that when I swapped the injector and the code didn't follow, that the injectors were probably fine. I also have a new Denso in #4 and it pulled a code also during the swap test. Am I not thinking right?
 

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The recall you're referring to has this symptom:

When the “no start” condition is related to the ECM (PCM), there will be NO spark or
injector pulse during cranking. Also, the Diagnostic Tester may fail to initialize with
the Engine ECM (PCM)
Your ECM is still firing injectors and spark plugs but with that many misfires I doubt that the ECU is able to pinpoint which cylinder is misfiring.

You've already checked spark and compression.

Take off the valve cover and inspect timing. There are marks on top of the camshafts that will correspond with the TDC mark of the crankshaft.

If that checks out okay then you should check fuel pressure and injectors.

Your symptoms sound a lot similar to this case: https://www.toyotanation.com/forum/131-corolla-8th-generation-1998-2002/1642294-2000-prizm-turns-over-then-immediately-dies-please-help.html

The OP had bad injectors and a major vacuum leak caused by improper reinstallation of the intake manifold. When you put your manifold back on did you remember to reconnect the vacuum hose beneath it?
 

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Rookie Wrencher with 2008 Corolla
2008 Toyota Corolla
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Discussion Starter #47
The recall you're referring to has this symptom:



Your ECM is still firing injectors and spark plugs but with that many misfires I doubt that the ECU is able to pinpoint which cylinder is misfiring.

You've already checked spark and compression.

Take off the valve cover and inspect timing. There are marks on top of the camshafts that will correspond with the TDC mark of the crankshaft.

If that checks out okay then you should check fuel pressure and injectors.

Your symptoms sound a lot similar to this case: https://www.toyotanation.com/forum/131-corolla-8th-generation-1998-2002/1642294-2000-prizm-turns-over-then-immediately-dies-please-help.html

The OP had bad injectors and a major vacuum leak caused by improper reinstallation of the intake manifold. When you put your manifold back on did you remember to reconnect the vacuum hose beneath it?
Great info, thanks. Looks like I have some work to do.
 

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Rookie Wrencher with 2008 Corolla
2008 Toyota Corolla
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Discussion Starter #49
The OP had bad injectors and a major vacuum leak caused by improper reinstallation of the intake manifold. When you put your manifold back on did you remember to reconnect the vacuum hose beneath it?
Yup, got it hooked up.

Thanks hardtop, that the write up followed to do the work. Excellent write up, made me aware of the hidden vac line.
 

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Rookie Wrencher with 2008 Corolla
2008 Toyota Corolla
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Discussion Starter #50
Take off the valve cover and inspect timing. There are marks on top of the camshafts that will correspond with the TDC mark of the crankshaft.
Looks like timing is on. Used the following diagram. I included a picture of my camshaft pulley marks with cylinder #1 at TDC.
 

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Rookie Wrencher with 2008 Corolla
2008 Toyota Corolla
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Discussion Starter #52
Update, while I had my valve cover off, it was easy to check my AF sensor. It was coated with carbon so I decided to replace it. I dropped the exhaust to check for restriction through the catalytic converter. No back pressure and it blew free. Replaced the O2 sensor while I was at it. The engine runs better, no smoke on start up and idles good for about 30 seconds, then starts to miss and blow uncombusted fuel. I shut her down so I didn't run too much smoke through my exhaust. All the smoke from earlier tests I think did my AF sensor in.

Check fuel pressure and injectors next since you've already checked for spark.
Don't want to buy the special fittings or tool to check fuel pressure so I'm just going to replace the injectors. Got injectors on order and will post update when I get them installed.

Here is a picture of my sensors. AF on the left.
 

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I'm just going to replace the injectors. Got injectors on order and will post update when I get them installed.

Here is a picture of my sensors. AF on the left.
Some people try to clean the sensors using whatever chemical or even lemon juice and have some success. Not sure how long-lasting the cleaning attempt is. What brand injectors did you get?
 

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I'm watching this thread closely.

Please report your results.
 

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Rookie Wrencher with 2008 Corolla
2008 Toyota Corolla
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Discussion Starter #56

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Rookie Wrencher with 2008 Corolla
2008 Toyota Corolla
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Discussion Starter #57
Returned the injectors purchased from eBay. Sent my originals to http://mrinjector.us. Fast turnaround and excellent service, got them back in less than a week. I have included his before and after report. Unfortunately the rebuild did not solve my problem. On startup it is still surging at idle, putting out smoke big time (smells of fuel) and dies after less than a minute. It is not misfiring like it was but I don't want to run her for very long to evaluate due to all the smoke coming out!

WHAT THE HECK! Good spark, good compression, timing is on, injectors rebuilt, cleaned, tested, parts replaced, what is going on?
 

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For the following you need to look at live data while your scanner is connected.

I need your MAF values at idle, even if it is misfiring/surging.

Next thing is to check the wideband o2/AFR sensor values - is it reading lean or rich while running? The ECU may simply be overcompensating by injecting excessive fuel from an AFR sensor that is stuck lean. You said that the car reeks of gas. We need to confirm that the sensor is functioning properly.
 

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Porsche
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The 30-sec mark is what we want data from before and after.

- MAF output before and after
- AFR data before and after
- intake-manifold vacuum before and after (most important piece of data)
- fuel-pressure in rail before and after

Don't replace parts before you test and measure them to confirm they are bad. Will end up replacing many perfectly working parts with brand-new perfectly working parts and your car's behavior won't change.

A short in AF-sensor wirin would cause it have low-reading and trick ECU into thinking there's lean mixtures and it will compensate by dumping in extra peteol. Did you ever run it with AF-sensor disconnected?
 

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Rookie Wrencher with 2008 Corolla
2008 Toyota Corolla
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Discussion Starter #60
Update, decided to throw in the towel and I took it to a mechanic in town. Turns out there was diesel mixed with the gas. Doubt it was operator error since the diesel nozzle wont fit in the tank. Guess my last fill had a cross over somehow.

Thanks to everyone's for your input! I appreciate you all taking me to school on this. I feel the time and money were well spent. I enjoyed learning and working on my car. Now I can lift the hood and know what most of those parts are and what they do.
 
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