Hello,

I have a Mazda 323 that currently will crank and not start. The engine will run on starting fluid. At the moment the car does not have a MAF sensor as it did not come with one. Surely a MAF sensor won't have any affect on injectors?

Fuses and relays tested good.

My initial thought was that the fuel injectors weren't opening. Listening to the inejctors using a long screwdriver while having someone crank the car yields no clicking sounds at all. Manually grounding or powering the injectors makes them open - so clearly the ECU is not grounding the injectors for some reason. I bought a replacement crank sensor since they're cheap and started looking into the OEM one that was on the car.

I found that the bracket was severely bent and that the sensor was pointing at the BLOCK and nowhere near the pulley. BINGO . . . I thought. I bent the bracket so that the sensor point at the pulley properly and set the air gap between 0.5-1.5mm with a feeler gauge as the shop manual says to do. No change in symptoms.

I noticed that the circuit for the crank sensor was only around 2.5v which looked strange to me, but according to the shop manual 2.5V is normal for this circuit. When cranking I notice this voltage goes up slightly (perhaps from the alternator?) but never drops. Should this be dropping as the sensor is activated to show that the circuit is being opened/closed by the sensor?

I pulled the entire main harness and checked the wires - all wires have continuity back to the ECU.

All of the shop manuals say something to the tune of "in 1999 Mazda started using a camshaft position sensor in these cars." However - the distributor breakdown shows that there is a "Camshaft position sensor" inside of the distributor. The distributor also houses the ICM and the ignition coil. There is a shutter wheel that passes by a magnet 4 times per rotation, but I thought that was just the trigger for spark? The magnet is strong. So if I'm correct it should work as follows:

Shutter wheel passes magnet -> slight voltage generated from magnet goes to ICM -> ICM tells car to connect voltage to the coil -> coil sparks and goes to rotor / plug wire. Nothing fuel related?

I figured maybe the injector driver has failed and that I'm barking up the wrong tree so I grabbed a junkyard ECU - no change again. The symptoms are 100% the same.

Any help is greatly appreciated. If anyone knows the theory of operation - what needs to come together for the ECU to ground the injectors it would be great to know!