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I am having an issue that the engine is turning over, but will not start. It was starting fine and ran great for awhile (just swapped it), then all of a sudden it will not fire. Has anyone ran into this? What was you solution(s)? I've been testing sensors trying to find something that is amiss. I am no Master Mechanic, so I am not exactly sure what the numbers are supposed to be. I have been able to find some info videos on Youtube University, but still in the dark about a few things. If there is a thread for this, please point me in the correct direction and forgive me.

It is a 2005 Mazda 3S MT. Just did a 2.5 swap (from a 2012 Fusion). Before you tell me THAT is the problem, it was running fine. I used the stock 2.3 intake manifold, and I am using the 2.5 injectors. The ECU is not flashed yet. Please check out my thread
https://www.mazda3forums.com/61-pow...o-much-do-not-enough-time-2.html#post10156384

I am not sure how to test the Throttle Position Sensor. I notice that it hums/whines when the key is on. I notice it has six wires going to it, and I am assuming three go to the TPS and three go to the motor to rotate the throttle plate...? Does anyone know how to test this?

I am not sure how to test the Mass Air Flow sensor. It has five wires and I am unsure what they do. Does anyone know how to test it?

I've noticed something weird with the VTCS solenoids (on the top of the intake manifold). When the key is on, the one on the pass. side gets warm (85-95 degrees F) and the one on the driver side stays ambient temp (60 degrees F) I think this is strange. Also, when I unplug and plug in the pass side, I hear an audible click. The driver side does not do that. Does anybody know why? What should they be doing when power is applied? Also, I tested them and came up with:
Pass- Ohms 36, 12.7 volts from connector green wire, continuity to ground on black/red wire
Driver- Ohms 31, 12.1 volts from green wire, continuity to ground via GREEN wire. I think that very strange the the same wire provides volts and is grounded. The black/red wire does not have power nor does it ground.

Other Test results:
-Spark tester- All spark plugs are getting energy
-However, the plugs are not wet with fuel, telling me injectors are not opening?
-Injectors are getting around 12 volts from the green/blue wire
-All injectors are testing at around 11.5 ohms each
-Crankshaft Position Sensor tests at 449 ohms (not sure what it is supposed to be)
-Crankshaft PS tests with .25 volts (alt) max when a metal object passes by it
-Camshaft PS tests at 462 ohms
-Camshaft PS test at .22 volts (alt) when engine is cranked over
-HOWEVER, I put the multimeter on the connector and get 2.1 volts (DC) from the green/white wire and 2.5 volts from the black/white wire. I find it strange that there is volts from both sides.
-ALSO, both wires going to the Cam PS have continuity to ground. Is this normal?

Is there anything else I should test? Am I missing something? Please let me know and I can post the results.

Thank you.
 

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This forum is amazing. I can not believe the abundance of people willing to step up and help a fellow Mazda Man in need.

Issue has been resolved. FOR ANYBODY WHO HAS THIS ISSUE AND NOBODY IS WILLING TO HELP: First thing I would look at is the VVT oil control selonoid. It must have been stuck with sludged oil. I took it apart and cleaned the screens and internals with carb cleaner, let it dry, reassembled it, and the car started right up no problem. There's a couple tutorials on YouTube University showing how to test these.

This forum is quick to comment on posts stroking each other's stickshifts instead of actually helping one another when someone has a problem. Hope your issue is resolved easily.
 
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