Engine shut off at a stop light...
 

I was driving my RX8 and decided to turn on the AC cuz it was kinda hot out about a week ago. Had it on for about 2 mins. when i came to a stop light and was waiting for the green light, i felt my car vibrate a lot like usual when the ac or heat is on, when all of a sudden it completely shut off on me. I immediately turned the AC off cuz i knew it was that causing it to shut off, I tried to restart it again, but no luck until the third time around, it started. Then the rest of that day and until now its still running like nothing happened, its doing good like always, no problems. I had it checked out by one of my rotary mechanics and everythings running good. Has anyone had an issue like that, or might have an idea of what it is???

You getting any noise from the AC compressor when you pop the hood and listen for a while (screech, grind, rumble, etc)? If the bearings or magnetic clutch are going it could cause the compressor to bind up which in turn puts more drag on the motor. If engine torque at idle isn't enough to overcome the drag from the compressor via the belt drive between the two then the engine will stall.

plugs and or coils. Have you had them replaced lately?

VOODOO, theres no weird strange noises coming from anywhere, xcept u could feel it rumble or shake a lot when im inside the car at idle stopped somewhere, with the ac on, n without it stills shakes but not as much. the engine never stalled on me thank god *knock on wood* lol...only that day it completely shut off without warning, like i turned the ignition off, like that. battery is new so it couldnt b the power. im always on top of scheduled services like oil change, last one was a month ago.

honestly, on december i told mazda if they could check them and they said they were still good, how long are they good for? but im gonna look into it...the car is running at its best right now and starting great, so idont think its that. but what the hell do i know..??? lol...thanks for the info thou. ill check them out anyways...

oh and another thing guys, while im here, the engine coolant light comes on everytime im on the highway and whenever its hot outside, its strange thou, i refilled it, and its always on the level its supposed to be, but the light still comes on, and its only on for like 20seconds and then it goes away then again comes on n then goes away right away. and its only on the highway. yesterday it came on again, so im gonna check it again right now.

when you filled it did you bleed the air out of the system?

search about the coolant issue its very common your sensor is going bad no big deal

no it didnt, but i filled it the next day when i hadnt turned the engine on yet...

thanks CF, iwill, you're probably right...ihope thats the case... :)

no prob man, I know how you feel when I got my car it was doing the same thing and I started freaking out lol, its just the sensor putting a little extra in the overflow tank may make it stop for a while.

there is the unit that interprets the sensors if this goes bad then it could account for the stall at the lights and the coolant sensor ...jus something to look into ...

Reviving an old thread.

I just had the exact same thing happen to me today on the way home. Was on the highway with the AC on (approx 60mph, 84F, 18 miles, pretty steady speed) when I came to a stop at a traffic light, the car stalled. I turned off all accessories (fan, AC, lights) and the car started back up. I held the revs at 2k until I got my green light and continued home. A couple more turns and I was home (1 mile maybe). In my garage I let it idle for a while, and it seemed fine. Turned on the AC and still seemed fine. I only tested it for a couple of minutes thou.

The car is an 04, 46k miles, all regular maintenance and up to date flash, K&N filter (been in there for 2 years, cleaned annually, most recently 1month ago). No CEL lights or other warnings. I had a question about ignition coil measurements, but didn't get any additional info. I think mine are testing poorly, but the car was running well till this happened. I ordered a new set, but they probably won't be here till next week.

OL!z RX8 - Did you ever find out what the cause of your issue was?

I would check your battery terminals and make sure they are clean and tight. A loose or dirty battery connection can cause weird problems. This has happened to me once before. Come to find out my negative terminals was loose.

Well, it doesn't look like it was my ignition coils...

https://www.rx8club.com/series-i-trouble-shooting-95/ignition-coil-readings-197801/

Battery connections seem fine too.

Low compression
Do a compression test ... I would be willingly to bet

Obviously I'm referring to the idle/stall/AC on issue not the engine coolant light

The same thing just happen to me. I was on the high way there was traffic and I turn the AC on and my car turn off. I got a compression test about 4 months ago and it was perfectly fine. Any idea was going ??

Same thing happened here and I changed my spark plugs, wires, and coils and thought I had solved the problem (only happened about once a month so was hard to troubleshoot). They didn't look bad, but I figured it couldn't hurt to replace them anyways. However, turns out it was my fuel pump going bad. It always started back up for me, but definitely don't want to be on a busy highway the one time it decides not to.

For those who do not know, it is a good idea to keep your fuel level above 1/4 tank.
Habitually driving with less can cause the fuel pump to overheat and shorten it's life.