Mechanics

MAZDA MX3 RPM PROBLEM

1993 Mazda MX3 • 220,000 miles

Car wants to die at a stop. When accessories are turned at idle like heater, lights, or touching brake pedal rpm's drop so low it dies. Recently tuned up, new vacuum hoses, new maf, no codes, tested iac valve and tps both react how their supposed to when unplugged and resistance is in correct range, injectors are clicking fine, cleaned throttle body and air boot, alternator is putting out 14.5 volts, new fuel pump and filter. Pressure is good, vacuum guage reads about 20 steady. Any ideas?
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Gatertamer
January 5, 2013.




Neglected to say it was 1993 mx3.1.6L. Sohc. Manual. According to chiltons it says if you unplug IAC when warm rpm's should drop. Instead. They go up about 600. Did resistance check and its within spec and thoroughly cleaned. What do you think?


Tiny
Gatertamer
Jan 6, 2013.
Should IAC valve move either in or out for this model with key on?


Tiny
Gatertamer
Jan 6, 2013.
The IAC should move in and out when the key it turned on and off.


Why don't you just open it up and clean it out with a bore brush and carb cleaner and see what happens-appreciate the B/U Joe-hope the holidays when well-TY


Tiny
Rasmataz
Jan 6, 2013.
Thank you. Done it a couple times. Took off IAC and turned key on it's gettin 12.5 V to it and it starts to spin rapidly and moves a little too. Plus the RES is right on guessin it works ok. On to something else.


Tiny
Gatertamer
Jan 6, 2013.
Did you try adjusting the idling speed?
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KHLow2008
Jan 6, 2013.
Thing is it idles pretty well. Rpm's drop a little when you turn on heater then a little more when you turn on lights then a little more when you hit brake pedal til it dies or almost dies. Is there another way to adjust idle than messing with TPS. ALT is putting out 14.5V same as what batt reads.


Tiny
Gatertamer
Jan 6, 2013.
Try doing this: Connect Diagnostic Tester (49 B019 9A0) to diagnostic connector and select SELF-TEST mode, or connect jumper wire between diagnostic connector terminals TEN and GND. Connect tachometer to diagnostic connector terminal IG (-).
If idle speed is not within specification, rotate idle air adjusting screw on throttle body.

Adjust to 700rpm


Tiny
Rasmataz
Jan 6, 2013.
Code 03 is appearing. Dist no g1 or g2 signal. Is there a simple way for a backyard mechanic to figure it out?


Tiny
Gatertamer
Jan 7, 2013.

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