Monday, 17 August 2015

Engine Tuning, Remaps, Fuel Saving

What is Remapping?

Most modern vehicles contain an ECU (or Engine Control Unit) that is a small computer which controls how the engine performs. it decides based on information from sensors and the drivers inputs how, much fuel and the timing of ignition or injection or both.
Vehicle manufacturers de-tune the engine by setting the software on the ECU to safe levels.
This is done due to the manufacturers having to sell their cars all over the world, this means that the software settings on the ECU must take into account different climates, laws & restrictions and varying quality of fuels. Not to mention irregular servicing and poor quality lubricants and filters.
Vehicle remapping is basically the modification/replacement of the manufactures default software on a vehicles ECU, to optimise the settings for our temperate climate, good quality fuel supply and regular servicing.

How is it done?

A vehicle remap replaces default software on the ECU, overwriting it with new software which can be programmed to optimize the cars overall performance. This is known as vehicle remapping because the ECU is essentially a program that controls how the engine is controlled. When your car is remapped, the tuned software is plugged into your cars serial port (or OBD port) which then overwrites the engine map with the new version to enhance engine performance. The ability to flash directly through the OBD has brought the tuning industry on leaps and bounds, with constant development on the engine now being much quicker via the flash process.
It has its drawbacks however as now anyone can remap your car, not just the specialist tuning companies.
Every couple of years the vehicle manufacturers improve the security of their software, which prevents remapping via the OBD port.
This is what is happening right now.
For newer vehicles the ECU has to be removed then opened and boot pins connected to the ECU circuit board. This is not for the faint hearted, and requires specialist up to date equipment.

It cannot be done with cheap clone tooling.
This will once again remove the cowboys from the industry, for a while at least.


Friday, 14 August 2015

Maths Test ( Ford Transit P0121) Pedal Position sensor circuit performance

Maths Test

A Ford  Transit was presented with a fault code stored for accelerator pedal performance.
DTC P0121- Throttle/Pedal Position Sensor/Switch 'A' Circuit Range/Performance.

Information systems suggest the causes for such a fault are;
- Faulty throttle position sensor
- Throttle position sensor harness is open or shorted
- Throttle position sensor circuit poor electrical connection
- Faulty Engine Control Module (ECM)


The easy option is to replace the pedal, but we prefer to test the component plus the power, ground and signal wires before condemning any parts or control modules.
It may take longer than picking up the phone and ordering the suspected part but it is a vital step in the diagnostic process.

The easiest way of testing the complete circuit is to use an oscilloscope.

Most older pedal position sensors use a variable resistance track that changes the voltage sent back to the module which is converted into a pedal position.
This method uses an analogue signal, which must be converted inside the module into a digital signal.

Some newer vehicles employ a digital sensor which can be utilised by the module without any further processing of the signal.
The sensor output is a fixed frequency variable duty signal which can be tricky to interrupt using the oscilloscope.
Check out the scope trace of the pedal signal.
This one test shows that the power and ground is good as well as proving the change in pulse width. 
The problem is checking the smooth transition from the idle position to Wide open throttle.

The use of a built in maths channel to display duty cycle is very useful.
To display the Duty Cycle on a Pico Scope you need to select Tools> maths channels>Create>Advanced>Duty>A>Next>Next>Next>Finish>Ok>
You should then end up with a trace like this;
It is now much easier to analyse the performance of the pedal sensor. Note the smooth transition from idle to WOT.


Monday, 3 August 2015

Diverter Valve VAG

We are still seeing plenty of diverter valve (DV) failures here at Gotboost.
The original factory diaphragm can crack under high boost pressure and create a massive boost leak. The new OEM valve features an upgraded piston type design modeled after the more expensive aftermarket units. This is the perfect solution for anybody needing an upgraded DV that does not want to void their factory warranty with "aftermarket" parts
The DV is a pathway for boost when it is not being used by your engine. Whenever the throttle body is closed, such as during gear shifts or deceleration, the boost needs an escape route or the pressure will build up and slow down the compressor. This can cause turbo lag or even damage the turbo.
A Blow Off Valve (BOV) or dump valve performs the same task as a Diverter Valve, but instead of returning the boosted air back into the intake, it vents it to the atmosphere making a distinctive noise.
We can replace your DV with the uprated part for just £76.25.