[DML] Re: Disabling Lambda
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[DML] Re: Disabling Lambda



The O2 sensor, temperature sensor in the valley and the WOT switch all provide a signal that the ECU uses to dictate the interval at which the frequency valve will open and close. I don't believe failure of any of them will cause the ECU to completely shut down the valve.

If the WOT is closed, the ECU will buzz at a fixed value that provides the most fuel to the engine. I don't believe that it totally shuts the valve though.

If the O2 sensor is cold or fails, the ECU buzzes the valve at a value that provides extra fuel to the engine.

If the O2 sensor is at operating temp, the ECU uses the constantly changing voltage from the O2 sensor to moderate the frequency valve, changing the fuel mixture in the rich/lean/rich/lean loop that we're all familiar with.

If the coolant sensor in the valley is below 68F, the ECU will again, buzz the valve at the value that provides extra fuel to the engine, all part of the "warm up" cycle.

Marc, you make a good suggestion that perhaps something is wrong with the valve that is wrecking the ECU. I'll certainly look into that. I think I even have a spare frequency valve somewhere.

My valve isn't doing -anything-. Either my ECU isn't switching it, or the (+) or ground for the valve have been interrupted. Unfortunately, I haven't had a chance to dig deeper into it. I hope to get to it this week and post a resolution before the weekend.


--- In dmcnews@xxxxxxxxxxxxxxx, Marc Levy <malevy_nj@...> wrote:
>
> Check that it is getting a good signal from the Coolant sensor in the Valley of Death..   Also check that your WOT switch is not stuck.
> 
> Both will cause the Lambda to misbehave.
> 
> If the controller is bad, maybe your frequency valve is pulling too much current??  I have not seen a schematic of the control unit, so I don't know what drives the frequency valve.  I assume it is some sort of transistor that could possibly be over-driven if there is too much current being pulled through it.
> 
> 
[moderator snip]


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