Help with Acceleration pedal signal

M

Milan78nis

New Member
Hi.
My name is Milan. My English is not too good but i hope that you will understand me and provide help.
I want to correct accelerator pedal signal. signal voltage range is from 0.98V depressed to 4.5V full

pressed pedal.
input voltage is 5v. when i hard step on the pedal, voltage jump is very instant and car hesitates.

is it possible to make some simple electronics device to correct signal and slow down voltage jump or

reduce rising to some point like 1.5V and than allow exponentially rising of voltage like without a

device. i was attached picture of what i want to accomplish.
Any idea? Using transistor or FET in circuit or something else? Any example? Thanks in advance!
 

Attachments

  • Acceleration.JPG
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Putting anything between the pedal and the management unit would be very dangerous. What if the device failed in the full throttle position? Just remove the lead from your foot, much safer.

Mike.
 
Thanks for fast reply. I understand risks,but my car isn't automatic and have two sensor correlation protection. My accelerator pedal is to responsive from idle state,and car is jerky when accelerate from idle. i need to smooth signal from idle to some middle point where everything is fine. I tried low pass rc filter but that didn't work well.
I you have some idea what circuit or component combination can provide what i want or in which direction i could look for solution i would be very
grateful.
 
You have probably heard this before, but the only safe, and possibly legal, way to fix your car is to take it to the dealership and have them look at the issue on the computer. They will be able to adjust throttle control, if that is indeed the issue, which I doubt. Positional throttle control is very, very reliable. To develop the symptoms you are describing suggests more than just an adjustment being required, if I were you, I would get it looked at sooner rather than later
 
I understand but car is already been tested and everything seems to be ok. problem is possibly in ecu mapping. i just want pedal to acting like it has very hard return spring and just for rpm from 800 to 1200 rpm because in that part car is jerking. that is signal voltage from 0.98V to 1.5V. is it possible to correct signal voltage depending of how fast is that signal changing? rc filter slows signal but in full range and causes override. any advice for simpliest solution if it is possible?
 
Without knowing how your ECU provides voltage to the pedal (PWM, PPM, DC ...?) and responds to pedal position it could be dangerous to add to or modify the circuit.
 
ecu spplies pedal potentiometer with 5v dc and. when pedal moves resistance degreases and voltage signal rises from 0.98v to 4.45v. i hope i could edit signal just in region of 0.98v to 1.5v. like engeage rc filter just in that region or some kind variable resistor that could decrease his resistance with rising signal voltage.
 
Are you completely sure it is not PWM or some other kind of modulation that jsut happens to look like if it were a pot on a normal multimeter?
 
I work for a company that manufactures these types of pedals and controls.
The controls have two functions:

--translate a linear or angular displacement into a value...that value being either an analog voltage, a PWM signal, or a CANbus message. In some instances RS485 has been used.
--provide an error value in case something goes wrong.

The ECU then maps those value changes into process controls. The ECU also reads any error values (i.e. going higher then 4.5 volts), and takes action to prevent a dangerous condition.

Based on my 8 years of experience analyzing and troubleshooting failures, I can give you an advice: don't mess with the signals. Even less so if it is something as critical as -in your case- the accelerator pedal.
Fix the problem, don't band aid it.
 
yes i am sure. i have dissasebled it. it is just potentiometer like egr or tps but only tps motor is controlled by pwm. i just want minor correction of signal. is it posible with simple circuit. i don't want to amplify signal just to slow downt in in lower region like on the picture
 
only cure is new ecu but that is too expensive. so i want to try diy mod with your advices and sugestions for simpliest circuit posible. car isn't automatic. i already try rc filter but large resistor or capacitor values throw erorr code in ecu.
 
I would try a more mechanical way. Something like a dash pot that keeps the throttle from closing too fast and stalling the engine. But rig it the other way to dampen acceleration.

I worked on Nissans in the 1980’s. Due to emission control, they ran very lean and would hesitate and pop on acceleration. We added a little resistance to the temperature sender circuit to make the ECU think the engine was colder. With a little more fuel, they ran fine.
 
i already try tweak map sensor to enrich mixture but that wouldn't help. is it possible to creat some circuit like voltage control resistance. where resistance would be high with low signal voltage and low with voltage rising?
 
i already try rc filter but large resistor or capacitor values throw erorr code in ecu.
Click to expand...
Any other modification or added circuit would probably also result in an error code. As you have already been advised by other forum members, for technical and safety reasons don't mess with the signal.
 
Vehicle year, make and engine? Is standard engine maintenance current (especially air filter).

When you "hard step" the accelerator, is the engine at normal operating temperature?

Have you checked the OBDII for error messages? You say engine was "tested" but by whom and how?

What is the idle RPM of the engine?

Any holes in the breather side duct work?

With no load (clutch disengaged), how does the engine respond to accelerator movement?

When did this problem start (presumably the engine responded correctly before this problem began)?
 
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