Recipe7

i searched and i didnt find something EXACTLY like my problem so imma just post it

today i left school at about 1 in the afternoon. It was about 100 degrees out. i got on the freeway. a few exit ramps were closed and there was some traffic. i was ridding the brakes for about 3 miles, and all of a sudden the engine just died on me. i am guessing it was because i had my AC up on 2, but this happens also when i dont have my AC on at all. i have no problem starting it up again. also i drive an automatic if that comes into play somewhere.

so my question is. What can i do to avoid the engine dieing on me in extreme hot weather (besides turning off the AC cause i hate melting)? And what is the problem specifically?

i drive an FD

thanks~john

maxpesce

Could be 1 or both of two things (or somthing else actually)

First :
The EARLY Auto FD ecu had a bad map for the close throttle condition that would cause stalling on decell w/ the AC on - These ECUs were recalled by MAZDA and will still be replaced by them, Check w/ a MAZDA dealer if yours is one covered by the recall. (mine was replaced before I bought it) This is unllikley as most all the bad ecu's have been replaced by now.

Second:
Autos are more sensitive to LOW COMPRESSION than the 5spds and whe the compression gets marginal (<7 on a Mazda tester) the the tend to stall at idle when the AC compress kicks on (I know from first hand exp) If the Compression gets really low (<6) it will stall any time you come to a stop as the engine wont have enough torque at Idle to overcome the drag of the torque converter. - Get a compression check.

Also any number of Vacuum leaks or bad soloniods could cause the problem,

911GT2

What about in a manual? the previous owner of my car told me that if he was stopped at a red light in the summer w/the a/c on, it stalled about 1/2 the time. Any ideas on that one?

maxpesce

Could be the Same problems, Low Compression, Vac Leaks, Bad Solenoids, or enven (i forgot to mention this before) a bad Idle Speed Control (ISC) unit.
AUTO's are just MUCH more sensitive to the Low Compression and vac leak problems b/k of the extra drag of the torque converter when stopped and in gear.

bajaman

I've experienced the same problem. I just set the idle a bit higher by adjusting the throttle-stop to where it idles at 1000 rpm rather than 700 - 800 rpm.
In the long run, I realized that it is just easier on me and the car to NOT drive it in hot (over 90 degree) weather. If the car is your only one or your daily driver, you are kind of screwed. It IS sort of embarrassing to have the car die and then you have traffic piling up behind you, isn't it?