Mazda 323 crank no start


I have a 1998 mazda 323 protege in my shed that I want to fix. It currently cranks but won't start. I've looked at the tachometer when cranking the engine and it doesn't move so I though it would be the crankangle sensor. I've had a look, cleaned up it's air gap and tried to test it's wires by back probing. One is ground, and both of the other two have 2.5volts. I would think one should have 5 or 10volts, at least something more substantial that 2.5volts.

I also tested what I think it the cam angle sensor and got 2.5volts on each wire (neither are ground).

Could there be a problem with the ecu.
The car battery was fully charged.

Thank you


  • Have you tried pulling the codes?

    • Yeah, I tried using an obd2 Bluetooth scanner with an adapter because it has a different pin config, the Bluetooth obd2 didn't seem to turn on so, that didn't work out.

      • 98 likely isn’t OBD2 in Aus.
        Google how to test CEL or MIL for your model. It will involve jumping a pin to ground, then switching the ignition on and counting flashes from check engine light.

  • Fuel pump

    • I can hear the fuel pump run when after I crank the engine, although that was another thing I don't believe the injectors are getting a signal and so aren't firing.

      • Possibly gummed injectors. To check injectors you will need some “noid lights”.

        You need 3 things for an engine to run, air, fuel and spark. Air is easy enough to check. Make sure there are no splits in pipes and clamps are tight.

        Next, listen for the fuel pump priming. Turn the key on and listen near the fuel tank. There should be a buzzing noise as the pump primes.

        Remove a spark plug, plug it back into the ignition lead or coil and ground out the threaded part of the spark plug back to the engine. Crank. If you are getting spark, problem is with fuel or air.

        As for the voltage on your Crank angle sensor, these seems about right. There should be an earth, a power and a signal wire, or possibly 2 signal wires. Power should be 12v but your signal wires will typically be 2.5~5v. If you google it, there is heaps of information on how to test crank angle sensors.

        • You need 3 things for an engine to run, air, fuel and spark

          4 - timing

          • @Peace Maker: Trust me, an engine with really bad timing will still run or at least sound like it wants to try and run. A car with no timing wont give a spark, so, it goes back to the three easiest things to check;

            Is it getting air? No, clear the blockage/issue, try again
            Is it getting fuel? No, check the fuel pump, fuel filter, fuel regulator, fuel injectors, fuel hoses. Fix the issue, try again
            Is it getting spark? No, check your coils/leads, plugs, crank/cam sensors. Fix the issue, try again.

            • @pegaxs: This, even if th timing is miles out and the engine with run, you'll know as you'll be getting flames out the intake or exhaust. Intake is the most fun, most likely to happen when you are looking down a carb throat.

      • is the car on a slant..then it prob is the fuel pump

    • Def sounds like a fuel pump to me

      Crank Angle Sensors are also super common on the Mazda 3/323 Etc

  • Had the same issue on an old car, crank but no start, and no tacho movement, new crank angle sensor wasnt too much, maybe $50, been running fine ever since i swapped it out.

  • Taking out the air filter and spraying a small amount of Aerostart or similar in the air intake should tell you if it’s a spark or fuel issue.

  • Your crank position sensor is probably dead. There are many different types of crank sensor, so you would have to consult a manual to find out what voltages you should have on what pin, but quite possibly, with sensor disconnected, from the ecu you should have an earth, 5v, and the last will be for signal back to ecu. The sensor could either ground the ecu, or supply 5v back to it, as a signal.

    Have you checked to see if you have spark? That would be the best place to start, and the easiest.

    • The spark plug fires once and only once, cranking for about 5 seconds. Also fuel injectors arent firing at all.

      Found out from my cousin, who used to own the car, that the mechanic was pretty sure it was the ecu that is the problem.

      Would a replacement ecu for this model need reprogramming? Or anything of that sort?

      • Do you have a service manual? That's what you need, to check if you are getting correct signals from crank and cam sensors. You can't just make a random guess at ecu without doing some diagnosis. You haven't mentioned what the engine code is. You may also be able to get "flash" codes from the ecu.

        If it has an immobiliser built in it may need programming, however I doubt this is a case on a 98 323.

        • I have the mazda protege 5 manual 2002 which I think is the correct one. Engine code is ceo4d16. I think the crankshaft angle sensor it working because when the key is in ignition and I turn the engine over by hand the fuel pump buzzes.

          Plan to test coil packs because spark only goes once. And compression because that is important.

          Could fuel injectors be clogged? and how could this be solved?

  • Merged from Replacing a car's ECU

    I'm wanting to buy a used ecu to replace the one in my car that I believe is faulty.
    I've heard from many different sources how this is done. And I don't want to confuse the two situations where you are installing a brand new ecu or a used ecu.

    Is reprogramming required to replace all ECUs or do some not require it, (older ones?) (certain makes?) Or if so what it the extent of what is required. (Could I do this at home)

    The car I'm working on is a mazda 323 1998 protege BJ 1.8L manual. If possible I plan to replace the ecu with an ecu that has the same part number from a used car.
    Thank you

    • Not an expert, but try searching in Mazda forums? This one is probably not specific enough and is more about insurance claims and getting out of fines.

      I would think that a factory ECU should just plug in and provided the battery has been disconnected should just re-learn as it goes.

  • Found out the timing was off, after finding low compression on one cylinder. So I fixed the timing but I don't think it fixed compression (I'll go further into that later on).

    The fuel injectors are now firing since the timing is fixed. But still no spark I wanted to test the resistance of the coil packs but can't find the specifications anywhere. This model has the coil packs next to the engine with lead running to the plugs, also i dont think the leads come off the packs without breaking.

    • Nevermind car runs just hadn't tested it till now. So just low compression. Thank you for the help guys.

  • Merged from Mazda 323 Starter Motor, Shorting out?


    I have a Mazda 323. When I try to start it, it cranks but very slowly and sluggishly. One time I held the key in for a while and the was a bunch of smoke from the engine bay. I found out the wire the connects the engine to the battery neg. was completely bare and after cranking was hot.

    To me this sounds like a short.
    I've pulled the started motor out and tested it out of the vehicle, it goes but the wires I used to connect it to the battery get very hot. Does the starter need to be replaced?

    The resistance between signal wire and ground (body of the starter) is 0.7ohms. And the resistance between wire that power the motor and ground (body of the starter) is 0.6ohms.

    • You will have a poor contact either within the solenoid, or brushes to armature. Replace starter.

      • Okay, Thank you

        • Battery is going flat. Decreased voltage = increase amperage. Increased amperage = melted wires.

          You are either cranking too long, not leaving enough time between cranking, cranking too often or your battery is low.

          You can either, stop cranking for as long, stop cranking as often or leave more time between cranks. Another thing to do is to replace your wires with much thicker ones. That way it won’t burn out the wires and only burn out the starter motor or the solenoid instead…