4 replies to this topic

[skp]

If I start the car up, it'll idle just fine between 700 - 900 RPM, but if I let the car coast while coming to a stop, the engine will die when the RPMs drop too low. I looked around a bit, and most of the material online seems to be about street Miatas. Regardless, the issue points towards either fuel mapping that's running too lean (not really sure what kind of mapping I have, but I highly doubt it's too lean), or the air intake controller. Any thoughts on how to diagnose the issue?

[Keith Novak]

It's either air, fuel, spark, or compression.  What have you done to diagnose the problem?  I've seen answers to that issue ranging from bad alternator to a mouse made a nest in the air box..

[Ron Alan]

Be careful speaking of mapping around here! Stock units are all the same. Altered ecu's are a no no in SM. If you suspect your ecu has been monkeyed with find a different unit. But odds are other than maybe a rev limiter crystal, your OBD1 unit is fine. Maybe Idle control valve? I know something can be adjusted in the TB...

[skp]

Just updating this thread: 

The issue was resolved. Turns out all the theories I had about air intake were for nothing...The idle was just set too low. At least, turning up the idle control solved the issue. 

 

I'm curious if there's an underlying cause. If I have low compression in one of the cylinders, the engine might not be able to catch a low idle, maybe? Any thoughts?

[Bench Racer]

If I start the car up, it'll idle just fine between 700 - 900 RPM, but if I let the car coast while coming to a stop, the engine will die when the RPMs drop too low.

 

I'm curious if there's an underlying cause.

 

Any thoughts?

 

The idle was just set too low.

Done deal, don't think yourself into future issues that you don't have.