Car doesn’t start in the morning? See why here!


it’s been a long time that in Brazil ethanol is present in fuel pumps in all stations, and that vehicles with flexible system that allows running with both ethanol and pure gasoline or the two mixed fuels are on the streets everywhere.


But with the arrival of cars equipped with this system, came together also a mountain of problems and defects that even good mechanics professionals suffer to solve.   More talk and let’s get down to business!

I will try to gather in this article some of the main recurring defects in automobiles with this blessed flex system, and I will leave some tips to diagnose and solve problems in the most generic way possible ie the tips can be used in vehicles of various brands, models, or years of manufacture.


This is what I see most happen out there and this can have several causes:

After leaving the vehicle unoperated for a period of approximately 12 hours or more, it simply does not pick up at the base of the stride.

Possible Cause(s):



First ly one should understand the operation of the flexible electronic injection system of the vehicles, because the ECM (engine control unit) or the car computer has a strategy or an (algorithm) to make the detection of fuel, and the adaptation of the injection, and advance ignition.

Such a strategy works more or less as follows in most cars:

When starting in the car engine, let run for a few minutes and turn off the engine the ECM will monitor the signal of the tank fuel level sensor for a few minutes and if during this interval the vehicle is fueled with a significant amount of fuel the ECM will understand that you refueled the car, and a strategy of recognition of the fuel that was added is adopted , and as soon as the engine re-operates the ECM will monitor the flow of exhaust gases through the signal of the oxygen sensor (Lambda Probe), and the adaptation and recognition of the fuel will be made according to the signal of such Lambda Probe.

However, the cat’s leap is that:

This step of monitoring exhaust gases is kind of time consuming, it can take up to 15 minutes for fuel to be recognized in some cases.  During this period of time the car engine cannot be turned off, if this happens the reconnaissance strategy will be aborted and recognition will not be successful which can make the next start of the vehicle difficult or simply impossible.

Don’t you get it? Calm!

I’ll give you an example of some unsuspecting drivers’ behavior that causes a flex car to leave the driver in the lurch:

João is the happy owner of a brand new vehicle with electronic injection system “FLEX”, João a few days is running with the car fueled with ethanol, because the fuel was cheaper and such.  Dai João da that little pass at the gas station that is only 5 km from his apartment, and realizes that the gasoline is cheaper and decides to fill the tank of the car with pure gasoline!  Happy of life he returns to his apartment that is close to the post where he supplied, to rest the rest of the day quiet without leaving home, and only intends to leave with the car again the next day early in the morning! ( POXA JOÃO QUE VACILO! YOU HAVE NOT RESPECTED THE PERIOD YOUR CAR NEEDED TO ADAPT TO THE FUEL YOU SUPPLIED).

To John’s surprise the car refused to run the next morning.  All because our friend there fueled 100% of a different fuel than it was in the tank, and walked a very short distance with the car so that the new fuel would be recognized by the car computer.

Possible solution to the problem:

If this happened to you and you’re in a place where a mechanic can’t get there, I’m going to give you a tip to get you off the nail.

I’m warning you: There’s no point pushing the car because the engine won’t pick up. 


The Battery must be 100% charged to start the procedure!

The right thing to do is to look for the vacuum duct connector that comes out of the car engine intake manifold and goes to the servo brake, and disconnects it to allow a little more air intake to “unburden” the car engine. After disconnecting the duct, step into the car and step on the accelerator until the end of its course and start at least 10 seconds. If the car engine does not pick up repeat the process by extending the starting time to 15 seconds, intersleaving with 1-minute pauses. Be patient, and after any signal from the engine pick up keep the throttle pressed until you realize that the engine speed has gone up.  The engine will run with some difficulty, and as soon as it improves its operation release the accelerator pedal gradually.

Never speed your car down with the cold engine! Speeding deep won’t fix your car. It’s about damaging it.  If after the steps indicated the engine still does not work, I’m sorry to tell you that your car will need to be towed for a workshop.

Mechanical and electrical failures that make problems happen frequently:

In vehicles with electronic injection there is a spy light on the dashboard that usually warns when something goes well in the engine and it should not stay on with the engine of the vehicle running:

Injection light on
The electronic injection anomaly light should turn on when turning on the key, and turn off as soon as the engine comes into operation. If it is lit all the time even with the engine running there is probably some possible problem in the injection of the car.

For the correct operation of the FLEX system, the following components of your car must be in order:

  • Ignition cables, candles and coils must be in good condition. The malfunction of these items causes ecm to adopt wrong strategies in the adaptation of fuel making the operation of the car poor and the performance and consumption unsatisfactory.
  • The cold start system should be fueled with pure gasoline, and should also be running 100% without clogging.
  • The oxygen sensor should also be working well, plus the catalyst should be 100% unrestricted. (Clogged exhaust also hinders the operation of flex vehicles).
  • The timing timing timing belt must be positioned at the correct point.
  • The tank fuel level sensor should be working fine as well.
  • And last but not least, the car should be with the engine in good condition (should not be burning oil) The filters should be conserved and the fuel supplied should be of good quality free of foreign elements and water.

If everything is okay, and the vehicle manual recommendations are followed then your car will work perfectly without hassles!

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