Question about 1994 Mazda 2WD B Series Pickup

2 Answers

Have 1994 b3000 3.0. repaired broken fuel line. engine cranked fine but would idle very rough. rev engine up and ran ok. took idle air control valve off and cleaned. engine then would crank and idle rough but will not rev up. trying to spit back like timing is off. now engine will only try to start but will not run at all. thanks for any help.

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  • jchristop387 Aug 19, 2010

    these sites really didn't help. can't diagnose without service manual. i really don't think the idle air control valve is the problem. the engine acts more like the timing is off. any more suggestions. thanks for the input.

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  • Mazda Master
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Here is the list that I know that you need to check and test:
* Can hear fuel pump running at start, fuel pressure at rail about 55psi. Dumped ispopropyl in full gas tank in case of water, replaced fuel filter.
* No spark, even with new plugs, wires, and coil pack (all tested with resistance in spec)
* Crankshaft position sensor tested fine, replaced it anyway, no change
* Cam position sensor tests okay (resistance and signal in spec)
* Wire harness between these sensors and PCM showing continuity
* PCM grounds all good
* Wire harness between coil and ECM showing continuity
* 12 volts to coil pack, but no circuit completion between hot and the 3 primary coil connectors when cranking engine (checked with test light)
* When connecting OBD2 code reader, no codes (I may have cleared them when I disconnected harness to PCM before testing) but can see some sensor data (temp, RPM, air flow).
* Passive anti-theft light goes out when cranking.
* Pulled PCM, looks clean, no burns (but a little moisture at pin connector)

Before to think in any PCM replacement, try this.

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Posted on Aug 19, 2010

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  • Master
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Hi,
Please check the bellow link to diagnose what is wrong with your car…
http://www.ehow.com/video_112584_troubleshoot-car-wont.html

http://www.2carpros.com/first_things/car_cranks_but_wont_start.htm

Let us know if you have somethin more to ask else accept the suggestion.
Thank You for contacting Fixya

Posted on Aug 19, 2010

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