Hello! I own a stage 3 ford focus mk2. The issue im facing is that sometimes under heavy loads or when fuel tank is low on fuel the rpms go only for 5k and it cuts, then the ESP SYSTEM fault comes on and lowers the performance. When i restart the car everything goes away as symptoms. The thing i noticed is that when i unplugged the maf sensor (i think that's how u call it) (located on the air intake before the air filter) the ESP system fault comes on. It is strange to me that maf sensor is related to such fault on the dash. Is the cause the sensor? What could be the cause? What is that about the tank being low and car stutters at high loads? Thanks beforehand!

I would hazard a guess a chipped to death wreck, being driven beyond its OEM design capabilities has popped the diaphragm in the sensor and the car gets so much boost it registers the movement but them see's its giving false data and throws it teddies

modified cars are normally worse to drive slower and nosier, with far less reliability - if you want them like this, you have to take the rough with the boost

plug in decent diagnostics and see what it says ?

32 minutes ago, Botus said:

I would hazard a guess a chipped to death wreck, being driven beyond its OEM design capabilities has popped the diaphragm in the sensor and the car gets so much boost it registers the movement but them see's its giving false data and throws it teddies

modified cars are normally worse to drive slower and nosier, with far less reliability - if you want them like this, you have to take the rough with the boost

plug in decent diagnostics and see what it says ?

The computer of the car didn't store this fault's code. The only one im getting is turning angle sensor and fuel pressure rail. I need to read it at the second it happens. Cuz when i got the car it had the issue, then i went to tuning shop where it got new chip and settings and this thing was gone for few months but now it is back and happens again regularly.

How were the diagnostic codes read, the best way is either the Ford system or Forscan to ensure both can busses are read.

Otherwise just guessing 

safety systems not doing what they expected tend to get to codes or lights - engine or transmission faults tend to give limp...  I don't think ESP should get limp, but quite likely some of its linked in with traction control...

as the weather is cold and horrible, summer tyres give up below 12C, and the salt makes the grease come out to play, its common at this time of year, to get wobbly if you press on.  I guess you know but may as well mention... ESP takes wheel speed readings from the wheel ABS sensors along with Steering column angle of dangle pushes this noise into a box of tricks connected to a yaw sensor (that measures how successfully you are asking the car to spin out of control), then a few algorithms in the box decide how much fun you are allowed to have.  

So any funny sensor data, or mismatched wheels and tyres front to back, can provide a bigger headache than the car was designed to cope with.  The circumference of all the tyres and the vehicle speed needs to be inside the threshold of error the computer believes is acceptable - otherwise it will start to take action to avoid a crash you may not be having (because it believes you are) ...

you may have two faults, too much boost somethings complaining / worn out - and funny wheels or faulty wheel speed sensors, (or indeed the steering angle sensor !).... and or altogether its too much and the computer says no...

on my non ford car the YAW sensor sits above the back axle in the boot and must be bolted where the computer wants it - if someone decided this bit of tat can be moved so you can get some decent amps and a sub in the boot - and thus if its not where ford put it - you might find that adds to the fun...

 

 

1 hour ago, Botus said:

safety systems not doing what they expected tend to get to codes or lights - engine or transmission faults tend to give limp...  I don't think ESP should get limp, but quite likely some of its linked in with traction control...

as the weather is cold and horrible, summer tyres give up below 12C, and the salt makes the grease come out to play, its common at this time of year, to get wobbly if you press on.  I guess you know but may as well mention... ESP takes wheel speed readings from the wheel ABS sensors along with Steering column angle of dangle pushes this noise into a box of tricks connected to a yaw sensor (that measures how successfully you are asking the car to spin out of control), then a few algorithms in the box decide how much fun you are allowed to have.  

So any funny sensor data, or mismatched wheels and tyres front to back, can provide a bigger headache than the car was designed to cope with.  The circumference of all the tyres and the vehicle speed needs to be inside the threshold of error the computer believes is acceptable - otherwise it will start to take action to avoid a crash you may not be having (because it believes you are) ...

you may have two faults, too much boost somethings complaining / worn out - and funny wheels or faulty wheel speed sensors, (or indeed the steering angle sensor !).... and or altogether its too much and the computer says no...

on my non ford car the YAW sensor sits above the back axle in the boot and must be bolted where the computer wants it - if someone decided this bit of tat can be moved so you can get some decent amps and a sub in the boot - and thus if its not where ford put it - you might find that adds to the fun...

 

Thank you for the detailed information! Really really appreciate that! I will try changing the angle sensor and see if this solves the issue. And u mentioned wheels wobbling. Since its a rwd on the wet roads when pressing the gas hard the tyres kind of wobble before they get traction for a few sec so this vibration and stuff may be freaking the computer. The car has camber and spacers if that's can be taken as a hint to the problem.