Helo i have a mazda 3 2005, this car overheating and we make a overhaul, but now this machine don start, no have fuel injection and spark fire, i dont know if have a over heating sensor, can help me

is this the Single head cam or twin version?
no photo of engine, so answers will be weak.

double posted. is this the single cam or twin cam engine?????? per side, the twin cam has 4 cams. 2 /bank.
i can not understand your questions, at all.
ok you overhauled the engine,
nor can i understand , still hard start.
does that mean it cranks slow and turn runs and drive perfectly ?
or cranks fast, but hard to start and runs perfectly?
or does that mean it cranks fast, starts, then misfires and runs crapppy-pappy?
hark, the devil really is in the details, no?

Generic answer.
all the wires and sensors , hoses not put back correctly.
oil full, coolant full, fresh gas in tank,
then you crank engine with no spark (I pull fuses)
and the crank it until oil pressure is good. yah, do that.

if really savvy, we check for top end oiling next. cranked only.


ok looks like oil pressure is good,(I don't want to wreck a new engine) (also check compression on a new engine, to see if we messed up., if not 150psi or more, you timed it wrong)



then we crank it, ok, it cranks and don't start
I check spark and it's timing using my timing light, it's wrong, i retime it, no and its ok. as is ..
ok sparks good, on all 6 cylinders. checked carefully and for static time.

so now start engine on test fuel,
if fails, see above for why.!
ok it runs for say 2-3 seconds and stalls. good.
We yell at the gas engine gods. O'BOY my engine seems to be OK ! progress....

next is fueling , ill stop now, as typing a book on fuel injection
is not easy here.
but fuel pressure is next. on all EFI engines. as is good fuel.
when did car last drive perfectly, 1 month ago,
10 years. what?
if long ago, the gas is bad. as are related parts all gunked up, like filters, and injectors.
and even the pump, or its sock packed in GUNK.
as you can see we have no history on the car, so.
really anything is possible. even vandalism.

btw we never just throw and engine in a car.
we check.:
1: compression, gee even sitting on a pallet.!
why install (6hr labor) a dead engine,?
2: then cranked oil pressure, spark/fuel off line.
same reasons.
3: then if all that is ok, I do check top end oiling now, if not any top end, the cams will not last very long. they will smoke and seize up in a flash.

this is how its done correctly, ask how.

is it fuel injected?

check if the car is firing by pulling an ht lead off the plugs and put another spark plug on the ht and earth the spark plug if it has spark when cranking if it is there check the fuel system if the fuel is getting to the injectors.

Listen for the fuel pump to turn on with the key ON. Do you hear it buzz on for a couple of seconds, and then shut off? If you do, the pump is working. If you don't hear it, the pump is bad or the wiring to the pump is not working. Check the relay.
Usually, on a four cylinder with multi-port injection, injectors 1 and 3 fire simultaneously, and then injectors 2 and 4 will fire at same time (because their ground wires are spliced together before entering the computer. When the computer internally grounds the wire, the injectors will pulse). Are you certain that all four are pulsing at same time? If so, that may be the Mazda way. But I think you are right to believe it is a fuel problem. Test the pump as stated above, key on (not start) and listen for pump to turn on.
Good luck.

It takes three things for a gas combustion engine to start and operate---air, fuel and fire---air is usually okay, fire sounds okay, according to you having "power", and the fact that it is intermittent---but still, check for spark---have someone wearing insulated gloves, unless they don't mind small pulses of 12VDC at about 50mA, which is not that bad, and have them hold a spark plug while still plugged into the wire very close to, but not touching, chassis ground. Or, put the spark plug while in the plug wire in a dark area, like down into the engine somewhere, and look for a spark. Either way, if your buddy feels a pulse or sees a spark, then you have fire. If not, it would likely be either the ignition module, usually in the distributor housing (under the rotor), or the ignition coil---you can obtain a schematic and check voltages if you wish---more often than not, in Chevys, it is the ignition module.

If you have fire, then it would be fuel related...depending on the delivery system (fuel pump, electrical or mechanical, or injection)---for an intermittent problem like this, it is likely electrical for fuel delivery, so not a carburetor or mechanical fuel pump---I would bet you have either tuned-port or throttle body injection---throttle body injection is one big port, like 1/2 carb, 1/2 fuel injector. If you have fuel rail injectors, then either they're all bad, or the ECM that controls them is dead (very unlikely)---my guess, if you have fire, is the fuel pump. However, I did have a Chevy Corsica with a bad injector (throttle body), which had the same symptoms.

As mentioned by you the fuel discharge is too much which seems to FLOOD the cylinders and so makes the firing difficult. So the fuel tuning must be done to ensure the correct pressure.
Also check if the spark intensity is good as if there is no spark there will be fuel flooding.
Have the fuel pump calibrated and the injectors checked, if not replace.

check for spark. use an inductive timing light on a plug wire while your trying to start the car and see if you have spark. if you do the next place to check is the fuel system. it it getting to the cylinders. just because the fuel pump works doesnt mean it is pumping fuel to the motor esp if fuel injected which requires a pretty high pressure of fuel delivery compared to mechanical fuel pumps. get back with me after you have checked these two items if it still wont fire or run. good luck. remember dont open up the fuel system and have any exposed fuel while trying to start the motor. very high risk of fire or explosion with this combination.

Timing is right, but the firing order is incorrect then it could not start. Make sure connection at the spark plug is in the firing order. Let get back to the basic: need spark and fuel. After several cranking, take plug # 1 out to see if it wet. If it is wet then you have fuel. If it is dry then you don't have fuel. Start to find out what is the root cause for fuel not coming. Now touch the spark plug to the engine chassis and have a helper to start engine. If there is spark strong then you have spark. If no spark then you know what to do: find the root cause of the problem. If you have spark and fuel then need to recheck timing by Top Dead Center: Piston #1 is up, mark at camshaft and 0 mark at crankshaft all line up together while intake and exhaust valve closed. Good luck.

Hello, I am going to make a few assumptions here. The vehicle has an electric fuel pump and you replaced it. The vehicle has fuel injection. The engine is actually cranking, just not starting, when you say "car still won't crank". You are getting fire to the spark plugs at the plug ends. You checked the fuel pump for power at the pump. No power, then you back traced the wire to the fuse block and checked the fuse to see if it was blown. If the fuse is good back trace the power to the ignition switch and/or ECM for power. You have power at the pump, check the ground and make sure it is connected properly. Will the pump run when someone turns the key on? Pump runs, check fuel manifold for pressure. No pressure, check the fuel filter for blockage, or replace it. Fuel pump doesn't run, new replacement pump is defective. There is usually some type of control module for the fuel pump on fuel injected vehicles. Good Luck, RAC

when you turn the ignition pump the clutch twice so the fuel pump doesnt inject fuel and hold the ignition till it starts dont turn it back just hold it