Very confusing 99 Corolla stalling issue

Hello! Please forgive the length I’m trying to be thorough.

My 99 Toyota Corolla has been stalling pretty much as soon as the engine heats up. It cuts off abruptly I lose high power things like steering and braking but dash lights stay on.

Eva 02 and cat sensors were showing on error codes.

It’s almost like clockwork how it shuts down. It’s very abrupt and I can’t start it again until it’s cooled all the way down to the point where the temperature needle doesn’t move at all. All these problems started when I put a little bit of steel wool in a hole in my muffler to silence it. I have as far as I know had the catalytic converter and O2 sensor lights on for a long time but it hasn’t stalled at all until I did the steel wool thing. What’s odd is that I didn’t put a lot in there just enough to plug the hole. It stalls every single time within 8 to 12 minutes of starting.

I also have a high idle (1500) when I first start in it hardly ever settles down below a thousand.

After it stalls I can crank, that’s no problem the only problem is it doesn’t turn over.

My RPMs don’t seem to have any effect on it stalling sooner or later.

I can’t emphasize enough that it doesn’t sputter or do anything aside from just die.

My battery is pretty old but I’m pretty sure my alternator is good though it may have some sporadic issues.

Because people at car parts places have been suggesting an exhaust issue compounded by an electrical problem and because my car just today started throwing crankshaft sensor codes… And this is a brand new problem. It starts up fine if it’s cold no problem at all so I don’t see how those could be related as they weren’t there at all the 100 or so times it’s stalled after warming up before today… but I thought it’s worth mentioning.

As far as some electrical anomalies that I’ve been having I’ve been starting my car occasionally with a much higher current deep cell battery as opposed to jumping it from another person’s car whenever it would run out.

You could say the problem is the car itself but Im far from Rich and I feel like there’s a simple problem though maybe two…

Any help at all is greatly appreciated and thanks for reading my novel of a post!!

I’m new to this forum and forums in general so please forgive and inform me if I’m doing something wrong.

A bad crank sensor can cause a sudden shut-down of the engine.

https://www.1aauto.com/content/articles/bad-or-failing-crankshaft-position-sensor-symptoms

Tester

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It’s the first time it’s thrown that code and it’s been stalling for weeks before that about 100 times. Well I do need to address this issue do you suppose that it’s the cause considering it wasn’t throwing this error when it was stalling prior and that it doesn’t have any trouble starting up cold at all?

That’s a classic symptom of a failing crankshaft position sensor.

The engine starts/runs when the engine is cold, but once the engine heats up and the sensor gets hot, it fails and the engine shuts off.

The engine won’t start/run until the engine cools down, and so does the sensor.

The article I linked also states: The check engine light doesn’t always come on, though, so you could be experiencing any of the above symptoms for some time before you see the warning light.

Tester

3 Likes

if you continue to drive like that,severe engine damage can occur…change that sensor ASAP.
I owned a 99 Corolla in the past and the CPS failed on it.I had to tow the car to a mechanic to get it replaced at $300. Use only Denso part on this car or else. Here is its location
Capturecps

Here is a diagram
cps

I own an early 90’s Corolla. My guess is somehow the change to the exhaust system’s exhaust gas routing (caused by the steel wool) is preventing the o2 sensors from working correctly. The o2 sensors on a 99 may not even be used by the computer to set the air/fuel mixture until after the engine warms up. Then once the o2 sensors start being used, the mixture is wrong enough to stall the engine. Just a theory mind you. But it would explain the symptoms.

The general problem you are having is that modern cars require air-tight routing all the way from the air-intake to the tailpipe. Older cars (pre-electronic fuel injection) were much more forgiving. On your car if there’s an air leak anywhere in that path the engine won’t run correctly. Suggest to get the exhaust system repaired, then if the crank sensor codes remain, replace the crank sensor. That sensor can definitely fail when it gets hot. With a little luck, that will do the trick.

It’s also possible the EGR valve is involved. That valve allows a little exhaust gas back into the combustion chambers to reduce emissions; but it usually only opens when the engine is warm and off-idle. If it opens too much, or at a rpm when it shouldn’t, that can stall the engine.

The higher than desired idle rpm of 1500 rpm when cold is probably normal. It seems a little high at 1000 rpm when warm, but doesn’t seem likely to be high enough to cause problems. Mine idles at 800 rpm warm for reference.

I realize you are looking for a quick, cheapo fix. I doubt there is one in this case.

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As soon as I punched holes in the cat all of the exhaust codes went away and suddenly I had the crankshaft code and now the crankshaft sensor seems like it’s totally could kaput cuz it won’t even start I’m going to order a new sensor per your advices. Any guesses as to what will happen when it’s installed and that’s not an issue anymore?

I ask because it seems like it came out of nowhere since it was not sending a code before when I had all the exhaust codes and it was already stalling. It stalled about a hundred or so times without firing the crankshaft code then when I had just pulled into advanced IT fired the code though it started up one or two more times

Is it possible it was creating the problems without sending a code until it got to the point it was a day away from breaking?

And thanks for all the help so far!

Also if it makes a difference there was a crack in the plastic housing around the nipple of the sensor itself it changed the angle between the sensor and the plugs coming out the back of it by about 2° at most. It bothers me because I had taken this car in and had that done about 10,000 miles ago and I think they used a really cheap part

There are several things going on with this car, but I expect the shutdown-when- warm will be fixed by a new, good CPS installed correctly.