Tribute won't start in the morning, please help
 

I own Mazda Tribute 2004 Gasoline 2.0 4x2 with Automatic trasnmission.
sometimes it is hard to start in the morning (only happend after i leave overnight), it crank but won't start.
The battery is OK and also I heard the sound of motor fuel pump (I conclude that the fuel is delivered)
I try to start many times but it won't start (more than 10 times).
After I leave it more than 3 hours I try again, and it start. Once it start it is easy to re-start again, after I turn it off and also I feel nothing unsuall when i drove it.
This problem already happend 3 times this year.
Can somebody tell me what might be wrong with my Tribute? or which part should I check? please help.

It may well be an issue with the thermostat. Probably it stuck open. In any case, it is better to get it checked if the vehicle is nearing 200,000 on its clock.

A thermostat problem will not cause starting issues. Why did you not suggest the IAC as you did in your other recent posts?

IAC wont make starting issues. even IAC is 100% malfunctioning, still the vehicle can be started without an issue. IAC cause stalling in low speeds, and die in idel when the Air Conditioner turns on.

Thurmostat is an essential part especially in cold climates. It keeps water without circulating, till enough heat is accumilated in the engine in initial start. Engine needs heat to sustain combustion.

This may not be the ultimate cuase, as there can be other issues also or not starting in cold.

Just wondering, how do you know the battery is still good. How old is the battery?

The IAC is a common issue for hard starts, internet search 'hard start iac' will show that. That is how my hard start problem was fixed.

There is no thermostat failure mode that will cause starting problems.

Thank you for all of you.
My battery is anly 3 months old. I'm sure that the battery is no problem.
I also not sure that the thermostart cause i live in tropic climate, but I will check.
Please note that when this problem happen there is no fire in the spark (I open one spark plug, put it in its cable and mount with the ground/body then start the engine).
I also already change the spark plug every 20.000 km
At the first problem I change the coil but this problem is still there.

Now you have some vital observations comming in. Trusting your spark observations, issues can be ponted at two systems (in general), ignition system and ECU.

Ignition system
You already ruled out the coil. Now its the distributor you have to check for faults. cleaning the contact points is an average skilled job. Don't forget to check the sprk wires also.

ECU
If the parks wont initiate, and ignition system is cleard for faults, then the problem may be with the ECU signal for ignition. If this is the cause, then there are many issues which can prevent ECU ignition signal, starting from a sensor fault to ECU eclectrnic or software issue. You need to hook this up with a scanner and check for faults. Does check engine light comes in (even momentaraly when the spark fails?)

The sure-fire way to rule-out IAC is to push the accelerator (gas pedal) slightly (making the throttle open) while engine cranks. If the engine still cannot be started, the issue is not with IAC.

IAC makes an alternate path for the air to enter into the intake manifold, bypassing the throttle body, so ECU can manipulate the amount of air going into the intake even the throttle is fully closed, managing idling. At the start (if the gas padel is not pushed), ECU send a signal to IAC opening the alternate air path. So as TomV mentioned, IAC can also cause starting problems, but can be ruled out as above.

Kavee,

You offer a clever technique to isolate the IAC based on theory of operation. I have only read about rapping the valve with a screwdriver to dislodge the stuck components. That may or may not work.