Technical Lambda Wire colours. Help Please.

[Darryl]

Hi,
my son has a 1997 1.1 Punto 55sx. I need to replace the Lambda Sensor and have a new four wire universal one.

Can anyone please tell me which coloured wire does what on the original Fiat Lambda Lead as i am going to have to join the new sensor to the old harness.

Thanks Darryl

 

[custard]

dont have the wiring colours however have you looked at the old one? often the OE ones use the standard colours after the mutiplug so the white,black and grey.
i wouild recommend getting an old connector to avoid cutting the OE plug off

 

[The Sultan]

I would recommend getting a genuine fiat part there much more reliable and so much easier to fit

the only wires you will be cutting are separated from the engine harness by a connector on the front of the gearbox or under the black plastic cover at back of the engine bay depending on weather it's mk1 or mk2

I cant imagine why anyone would be cutting into the harness after this connector anyway custard

universal lambda sensors don't come with long enough wires to reach it anyway

 

[Darryl]

Thanks Littlepip?

I already stated that i have bought the replacement Lambda so i am hardly liable to go and buy another.

I needed advice re wire colours. I am a fully qualified engineer and 5 minutes with a soldering iron will not phase me and i have every confidence that it will be fine

The replacement was £21 , genuine Fiat £66. Car cost £300 work it out.

As for the wires on the replacement being too short to reach that is why you cut the existing lead near to the old sensor so that there is a load of spare cable to join to the new one.

Honestly i am not trying to be awkward but read your post again and ask yourself WAS THAT HELPFUL?


Meanwhile can anyone answer the original question please.

Thanks Darryl

 

[The Sultan]

yea fiat use black white and 2 gray it doesn't matter which way round the gray ones go as this is just the pre heater

the wire you will be cutting into is not part of the engine harness so no bother if you muck it up you could get another from the scrappy and plug it on

hay that's a point why didn't you go to the scrappy and get one for a fiver

as for soldering the wires well you'll struggle

it is not possible to solder stainless wire with normal soldering iron and solder

you need to get 4 crimp on connectors should have come with the sensor it's self they normally do

if not you need to get some "stainless" or rustless crimp on connectors

or you will be back were your started engine light on bad running only next time it will be down to bad corrosion on exposed wires under your car

this is the main reason why I say it's better to get original parts as all the wiring is sealed

it might of been 20 quid but in the long run may cost you 66 to put right anyway

 

[Darryl]

Spot on!

Thanks for that , really do appreciate it.

As you say the new one has come with crimps and shrink wrap sleeves.

Didnt bother with the scrappy as there was no guarantee it would be any better than the one i was removing.

Cheers Darryl

 

[T14086]

Thanks Littlepip?

I already stated that i have bought the replacement Lambda so i am hardly liable to go and buy another.

I needed advice re wire colours. I am a fully qualified engineer and 5 minutes with a soldering iron will not phase me and i have every confidence that it will be fine

The replacement was £21 , genuine Fiat £66. Car cost £300 work it out.

As for the wires on the replacement being too short to reach that is why you cut the existing lead near to the old sensor so that there is a load of spare cable to join to the new one.

Honestly i am not trying to be awkward but read your post again and ask yourself WAS THAT HELPFUL?


Meanwhile can anyone answer the original question please.

Thanks Darryl

Firstly you come here asking for help...littlepip gave his thoughts to which I totally agree.Ask yourself this....whats the difference between a £21 aftermarket pattern lambda sensor and a genuine £66 original fit part? I'll tell you shall I,the quality of metals used in the composition of the sensor.

I have seen many cars fail MOT's over the years due to emissions then return with a aftermarket lambda sensor and still fail......only to pass when a genuine sensor is fitted.

Return the sensor & buy a geuine one & plug it straight in?

 

[dave]

lots on here have had trouble with the after market ones, i would prefer to try the used one from scrappy or new oem one my self

 

[Darryl]

Okay,
i am always prepared to listen however until i have tried this replacement i wont know.

That takes me back to the original qustion ie which colours do what.

I am already aware of the 2 grey heater wires . That leaves white and black. One must be negative one is trigger . Any ideas as to which is which?

Cheers Darryl

 

[T14086]

http://www.lambdasensor.com/main/mcolours1.htm

 

[The Sultan]

lambda sensors tend to be quite reliable they tend to give trouble when something else regarding emissions is a miss as raw fuel will cook them in the exhaust and cause failure

the only reason I have ever replaced a fiat lambda is due to the pre heater not working the sensing side of them is normally functioning fine when the engine is warm but the light remains on due to the open circuit

most lambdas on well locked after cars will last well past 100k