wideband oxygen sensors

A wideband o2 sensor allows for much more accurate  fuel sensing for the  ecu.
wb sensors produce a signal up to five volts unlike standard  o2 sensors that only  reach 1v.
we will have a good look a diagnosing wb sensors at a later  date using live data  graphs directly from the software we use to monitor them

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lunar auto diagnostics

Full range of engine fault diagnostic services Contact us for help

125,east bawtry road
Rotherham
south Yorkshire
s60 4lq

MAF meter

Waveform  produced by an airflow  sensor.These sensors measure the amount of air entering your engine and are vital to the engine running correctly.
The sensor  produces a voltages that varies   airflow shown here on an oscilloscope.Starting at .5 volts the the engine revved giving 4 volts.The shape of the waveform  is the key,a peak followed by a drop as the engine  slows down

 

Tel:07891903013

A correct maf sensor  waveform

lunar auto diagnostics

Full range of engine fault diagnostic services Contact us for help

125,east bawtry road
Rotherham
south Yorkshire
s60 4lq

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Many thanks Lunar  auto diagnostics

 

Tel:07891903013

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lunar auto diagnostics

Full range of engine fault diagnostic services Contact us for help

125,east bawtry road
Rotherham
south Yorkshire
s60 4lq

Yike old OBD1

below is the  dreaded LED flash code indicator  from an OBD1 volvo.
These very early systems would strand you before any dash light or codes were set.
Prior to these system there were sockets  from all the manufacturers  with their own systems.This meant  using the dealer equipment or bridging pins to put the ecu into diagnostic mode.

lunar auto diagnostics

Full range of engine fault diagnostic services Contact us for help

125,east bawtry road
Rotherham
south Yorkshire
s60 4lq

fuel trims

Fuels are  variations added by the ecu to allow for wear and tear in sensors and the engine itself ie valves pistons etc.
A  recent case with a vauxhall zafira illustrates this.Testing the 02 sensor off the car  found it to be  very sluggish.A new sensor was  put in  and the short term fuel  trims began to change  but the long term  stayed at 12.5  after dropping from 14,1 with the  short term fuel trims at zero.


Below the live data  before  the o2sensor  was fitted  notice open loop

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After the new 02 sensor was fitted  note short term trim now giving data and closed loop.
Long term at 12,5 will drop as the ecu  adapts to the new o2 sensor

lunar auto diagnostics

Full range of engine fault diagnostic services Contact us for help

125,east bawtry road
Rotherham
south Yorkshire
s60 4lq

the computer relearn procedures

after a sensor as been fitted  the engines computer take a while to  adjust to the data so it may be 200 miles before everything is back to normal

A typical waveform produced by the rpm sensor

Using an oscilloscope  gives us direct access to a sensors output to check it is functioning as here  an rpm sensor.
These can give problems with  warm starts,an oscilloscope immediately tell us every thing is OK with the sensor and even going on a drive to check the sensors operation  under different conditions i.e. full engine  under bonnet temperatures

lunar auto diagnostics

Full range of engine fault diagnostic services Contact us for help

125,east bawtry road
Rotherham
south Yorkshire
s60 4lq

checking your cars current state

We provide a  service to check your cars  current engine state of tune or its sensors.
If need be we can back up a live data check with oscilloscope checks
Oscilloscopes are old school and very powerful diagnostic tools

if you have problems with  your car that are unresolved let us know

Tel:07891903013

lunar auto diagnostics

Full range of engine fault diagnostic services Contact us for help

125,east bawtry road
Rotherham
south Yorkshire
s60 4lq

studying the live data

Live data is just that,live communication between the engines ECU and the sensors that gather information.
These sensors  measure temperature,air flow,fuel   mixture etc that the engine uses  to run the engine but the computer or ECU as a built in parameters that it can apply when the information from a certain sensor is corrupted or of low quality..
The engines computer can correct for developing engine problems but after a certain point it will give up and set an error code that will light your engines  malfunction light on your dashboard

Below is typical  live data display.no engine codes have been triggered and all data is  well with in bounds

lunar auto diagnostics

Full range of engine fault diagnostic services Contact us for help

125,east bawtry road
Rotherham
south Yorkshire
s60 4lq

details of the secondary waveform

A secondary ignition waveform contains a lot of precise and detailed  information.
In most mechanics eyes it merely  solves faults with ignition leads plugs etc.
But there is a much deeper level to this.
Fuel mixture leaky valves low comp all  can be diagnosed with  this  waveform and a lot more besides

lunar auto diagnostics

Full range of engine fault diagnostic services Contact us for help

125,east bawtry road
Rotherham
south Yorkshire
s60 4lq