High CO , need advice :-)

[Droll]

Got a bit high values on the MOT, before  I started bouth CO and Lambda was to high, afther some tingelig the Lambda value was ok ..

Engine :KFX (TU3JP)/KFW (TU3JP)
Car : 2000 Berlingo Van ...

Did a full service on the engine ( Oil, oil-filter, air-filter, plugs )
Also changed the lambda sensor ( only one ), and air temp sensor, engine temp, pressur sensor inside intake ...
New Catalysator, and checked the rest of the exhaus for leaks ...

Got a readout from the ODB2, and it told me there was a break in the wires for the lambda, was reset but came back ...
Next I checked the wires from the ECU plug ( SL96 ECU ), found the wires (pin 4 and 22 ), bouth close to 0 ohm .. so no break

Then messured the output from the lamda ( between battery - and sensor wire >> was between 0,8 and 1,25 V ..
THEN I checked between + and - on the sensor itself >> there it was between 0,55 and 0,8 V??

Isn't the sensor minus and car minus on the same level/potetial  ??, messuring between minus sensor and battery earth gave me 0,4V, was expecing close to 0V  

Any advice :-) , ned to stabilate the CO below 0,5 ....

Arne Kjetil

[Droll]

Bump :-)

Any advice ?

I think I have tried my ideas and then some...
Short story ... I don't thing my ECU does respond to the signal from the Lambda, therfore runs to rich ...

A readout from the ODB2, tells me about a broken wire to the Lambda, this is were I am lost ....
It's only 4 wires, and I have traced them all from the sensor to the ECU ...

1 +12V in to the heater ... checked ok
2 Ground heater, traced back to the batteri ( - pole ) and pin 36 and 54 on the ECU .... checked ok ( 0 ohm)
3 Negative signal/ground ? from the lambda, goes into pin4 on the ECU ... checked ok ( 0 ohm)
4 Positive signal from the Lambda, goes into pin22 on the ECU .... checked ok ( 0 ohm)

Heater draws around 1.3 A from the batteri, sounds about right ?
Voltage between pin 3 and 4 are around 0,8V ... goes a bit up/down ... sounds about right ?

Lambda sensor are new, have tried 2 different sensors .... same result
Wire conector to the ECU have bean cleaned/ sprayed with electric cleaning spray...
Have tried a secound ECU unit, the current one are a checked unit from Cartech Electronics Ltd ...

The locale shop did read out some error codes from the ECU, tried to erase them, but they came back ....
Don't know the exact codes, but was told it was a broken wire for the Lambda ???... but all wires I found was fine..

Any advice ??

[Droll]

Quick question ...
Does anyone have a wiring diagram for the ECU/lambda for this car ??

Might have something, but neeed a wiring diagram :-)

Thanks
Arne Kjetil

[cancunia]

I'm guessing you have a petrol engine? What size is it?
Sorry, I don't understand the engine codes in you first post.
Might also be helpful to know what the codes were from the local shop.

[Droll]

I'm guessing you have a petrol engine? What size is it?
Sorry, I don't understand the engine codes in you first post.
Might also be helpful to know what the codes were from the local shop.

Yes petrol :-)

1.4L

Didn't get the exact code #, but I think it was something like "heater circuit failure (open circuit)" ...

But the heater DOES work, it draws 1.3A... suspects there are a short to ground on the ground wire ? ( controlled from the ECU by the ground wire )

[Gadgetman]

I may have some schematics...
Depends on which ECU you have.
(I have a Haynes manual that contains ECU wiring diagrams)

[Droll]

Depends on which ECU you have.

Got the Sagem SL96 ECU ...

[Gadgetman]

According to my 'Haynes Professional Techbook 3558 Engine Management and Fuel injection system, Pin Tables and wiring diagrams Volume 1'...

The Heated Oxygen sensor have 4 pins;
1 - To Gnd.
2 - to 'Fuse 11, 15A rating' The other end of this is connected to 'Intake Manifold heater'(if that exists on this car? can't seem to have noticed something like that on mine. ) and to pin 6 on 'Fuel Pump Relay'.
That is the heating part of the sensor.
Pins 3 and 4 is the sensing wires, and they seems to be in a shielded cable and connects to pins 4 and 22 on the ECU.

The connector has 3 rows of pins, 1 - 19 is row 1, 20 - 37 is row 2 and 38 to 5 is row 3.

If you're uncertain about which is Pin 1 and so on, then pins 1 and 2 should connect to the injectors, and coil-pack is on 37 and 55.
(The TU3JP4 has both 'wasted spark' - 2 plugs firing at the same time - and 'out of turn' firing of injectors into the inlet manifold, a 'wet manifold' system. It may be possible to improve fuel efficiency and power by swapping out the loom and the ECU with one that fires the injectors singly instead of in pairs)

[Droll]

Yesterday I cut open most of the wiring harnes for the engine, traced all wires for the lambda sensor...

• +12V in to the heater ... checked ok.
  
•  Ground heater, traced back to the batteri ( - pole/ground ) and pin 36 and 54 on the ECU .... checked ok ( 0 ohm)
  
•  Negative signal/ground ? from the lambda, goes into pin4 on the ECU ... checked ok ( 0 ohm)
  
•  Positive signal from the Lambda, goes into pin22 on the ECU .... checked ok ( 0 ohm)
  
  

Had some hopes for a problem with the groundwire ... found this online ...
But no, the ground wire fron the sensor was soldered together with the main ground for the ECU inside the harness ( stock )

I do know the heater does work ( draws current/ gets worm ... )
I do know the wires for the heater are ok, but still the ECU tells me there is a open wire/broken wire ...

So my main question now  ... how does MY ECU sence a broken wire ?, are there some sort of sencing function on the positive side ??

Any chance they have made 2 almost indentical lambda sensors, only difference are some switched signal/ground wires on the lambda signal ??


Arne Kjetil