Lamda yes or no

[skdub]

Had running problems with T25 California 2.1 (non cat) .. overfueling - running like dog ..

Various things changed - ecu,air flow meter, fuel lines, temp sensor etc .. no joy

Lamda was recently changed ...

When lamda is unplugged it runs fine ... do i need it and why maybe would that be

any thoughts appreciated ..

[MGP]

Unplugging the lambda sensor will put the ecu I to fault mode making it run on a Base map.
Have you checked the temp sensor with a multimeter? Same for air flow meter and lambda.
What lambda sensor was fitted as I have had many problems with the cheap generic type ones.


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[skdub]

Lamda was from heritage ... temp cooling sensor changed ...AFM changed and even ECU changed ..

By not using the lamda what effect will it have on the engine ... seems to be running much better without it

[ajsimmo]

Sounds like it could be a high resistance in the circuit making the ecu see a lower voltage, thinks it's lean and pumps more fuel in. If it sees no voltage it defaults to open loop map (safely on the slightly rich side).
Check wiring, connectors and earth points.

[skdub]

Thx Andy , would it hurt to run it without lamda,,,, I mainly run on lpg

[ajsimmo]

If you run on single point open loop lpg then O2 sensor does nothing anyway. If you run multipoint injection lpg then best get another new sensor, as gas fuelling will also be controlled by ecu and will mirror petrol.

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[skdub]

Andy,

Not sure what system is other than Gasure ....

It seems to be running really well on both gas and petrol with sensor disconnected. .. Has always ran well on gas regardless of sensor its just petrol that was the problem...

Does it harm engine at all by running on petrol without sensor .... it seems fine now on the petrol with performance and general running without it

thx steve

[Aidan]

The VW ECU needs the correct lambda signal, only use the correct Bosch lambda, there's a generic Bosch one (about £65) which works with all the mid 80s/early 90s VWs and has the correct plugs on it though the cable is over long for our vehicles as it will also fit fwd cars with the probe further away in the exhaust under the car
iirc ours has a more square wave signal than the current types and other generic ones, so even though you can test the output on those and it makes sense the ECU will not listen to it, will only see the low signal and will just run rich
the subaru ecu will happily run with a cheap £13 lambda

[skdub]

Thx Aiden,

Will any harm be caused though without using one ..... seems to be running fine without it

[R0B]

It's Aidan not Aiden.He's not keen on folk getting it wrong.