Engine dying while braking

Hello everyone, as my name implies I’m the sort of person who is uncomfortable adding oil, however my brother is a maintenance tech so if you have to talk a bit over my head i’ll have him read this.

I drive a 1995 Toyta Corolla. Two things that I should mention that may or may not be relevant. I have a history of electrical issues (I’ve replaced my alternator 3 times) primarily when it has been wet outside. I have also noticed smoke under my hood. I was initially scared this was an engine issue, but my brother assures this is due to a power steering leak

The issue at hand:

For the last couple days I’ve noticed a few things worth mentioning. First my brake light has come on a handful of times, however oddly never when actually braking. Secondly, my enigine will sometimes but not always stop running when I brake. At this point all my electrical systems still work (lights etc.) and all the lights on my panel come on (which I understand is normal if a car is on but engine not running). Lastly, my car has never not stopped, but it has been for the lack of a better term “mushy” for a couple weeks.

When I go to start the car again after this engine stop, sometimes it will immediately start, sometimes it will struggle (rewr rewr rewr) but then start, sometimes it will struggle and go to battery noise ““click click click””, and if we start getting the battery clicks it stays there until jumped.

My brother today went and checked my battery with an multimeter, and he states that my battery is both maintaining a charge and charging (He told me to tell you he got Cold not started 12.3 volts, car running 14.48).

Any advice? Unlike some others ive noticed when lurking, I will come back and answer questions, as I am seeking your help after all.

Thanks :slight_smile:

Well, it sounds like you have a short to ground in your brakelight circuit. Hopefully it’s in the switch that gets released by the brake pedal lever to complete the circuit when you press the pedal. These are affordable and easy to replace.

Since the brake light circuit is “always hot”, so that your brake lights illuminate for safety even when your engine has died, a high-resistance short to ground in the circuit could drain your battery when the car is parked. Your brother should be able to test this very easily with his multimeter.

The staling is a different problem. It could be the IAC, that controls your idle when stopped, or even a vacuum leak in the brake booster. The booster can be checked by pinching off that vacuum line and seeing how it affects the symptom. The IAC could probably be brought back to life with a good cleaning… unless the IAC motor itself is shot.

Or you could simply have a common vacuum leak. After 20 years in service, the rubbery things dry up. If it were mine, I might buy a roll of vacuum line and replace the lines, ONE AT A TIME so they don’t accidentally get crossed up. If you pull them all at once you may end up saying “s***… where WAS that line connected to?” Many, many people have.

Another suggestion would be a compression test. Post the results.

The effect of the “wet” could be that it’s turning your high-resistance short into a low-resistance short. Or it could be moisture getting into the distributor (if this '85 is a distributor-based system). Or even moisture penetrating some other part of the ignition system. That one will take your brother to diagnose.

However I did miscommunicate. It is not my brake lights (what shows other drivers i’m braking) that came on, rather it was my brake warning light (what indicates to me there is a brake problem)

Does this help clear things up?

Thanks again for your response.

It makes a world of difference.

The brake warning light may be illuminating when you apply the brakes because your brakes are worn out. As the pads wear, the fluid moves from the reservoir to the calipers. When the brakes wear sufficiently, the fluid in the reservoir drops to where a float trips the brake warning light. That’s totally unrelated to your other problems, but you DO need to get your brakes checked.

My comments on stalling stay pretty much the same, except that the comments on the “high resistance short” draining the battery and turning into a “low resistance short” are no longer relevant.

Thanks for the correction.

The odd thing is, the light did not come on when i was braking, It came on while i was driving. They just came on and then went off a few seconds later. That does admittedly sound like a short.

So the brake issue does not seem related to the engine dying while braking issue?
My brother checked the vacuum line into the check valve there was no apparent cracks or holes. When he pulled off one of the hoses however the engine began to run very rough. When he put his thumb over the end of the line it returned to running smoothly. Does this help at all?

Regarding the engine dying when you brake, I would suggest taking a look at the Mass Airflow Sensor (MAF)–assuming that this engine has one. It is possible that a 1995 model doesn’t have a MAF.

Regarding the brake warning light, I hate to play Captain Obvious, but–here goes:
Has anyone bothered to check the level of the brake fluid?
Has anyone checked the condition of the brake pads/shoes?

Brake fluid low because of worn pads. Also, check all the brake lights including the back window. A burnt out or flakey bulb will turn on the light. This car has an iac I would clean it. Clean the maf with sensor safe cleaner.

The light being flakey does not indicate a short. It indicates that the level is right about where the float will trigger the light, and as the fluid moves around, or when the brakes are used, or if the road changes pitch, the float and the light will respond accordingly.

I’ll take another tack on this one. I think it is the power brake booster that’s the problem. It’s powered by engine vacuum. The rubber diaphragm has split, creating a vacuum leak, and that is allowing unmetered air into the intake manifold, resulting in a poorly running engine in general, and stalling when braking.