Re: [DML] delayed acceleration problem

["Walter" <Whalt@xxxx>]

John,

Remember that the problem I am having now is only while the engine is cold
and only during the first two minutes or so of operation.

Now for some theory: When the engine is cold, a coolant temperature sensor
tells the Lambda ECU to ignore readings from the O2 sensor until it has had
time to warm up. Until warm, the ECU sends a fixed duty-cycle signal to the
FV.

So even if my O2 sensor were bad or contaminated or even missing, it
wouldn't matter during warm-up. Now perhaps maybe something involved with
my coolant temperature sensor is malfunctioning causing my Lambda ECU to
look at the O2 sensor before it has warmed up? Having a stuck coolant
temperature switch or a bad electrical connection associated with it could
cause my symptoms.... maybe? Any ideas?

You say:
> If the FV isn't getting the
> signal, then you were most likely running rich which it is supposed to do.

I'm not so sure about this. I think you have the logic backwards. I
thought that a closed FV causes a lean condition. Go to page D:04:08 of the
Worship Manual (huh, excuse me, I mean the Workshop manual) and let me know
what you think.

Several months ago before I even knew I had a frequency valve, I drove the
car a lot without the valve buzzing at all. The cause turned out to be a
bad Lambda relay. Could this cause the O2 sensor to get contaminated? Once
contaminated is the damage irreversible? Or does plenty of normal driving
burn it clean?

You say:
> The louder it gets the harder it 's working to put more pressure on the
lower
> chamber of the fuel dist to lean the gas.

I have heard frequency valves that were considerably louder on some
DeLoreans and more quiet on others. But I'm not so sure that the valve gets
louder when it works harder. More theory: If I understand it correctly, the
amplitude (signal strength) to the FV does not ever change. What does
change is the duty cycle of the signal according to what the Lambda ECU
determines. If there is ever any audible changes from the FV, they should
be one of pitch and not volume. Comments anyone?

You say:
> My first thing then would be to adjust the air flow meter
> to compenstae for the 02 now being contaminated and when you put a new one
> in, the readjust back to the way it should be.

I have a new O2 sensor on hand, and my odometer has 16K miles on it. Should
I replace the sensor now or wait until I get 30K miles on it or more? I
suppose I need an exhaust gas analyzer to properly adjust the air flow
meter. No?

DeLoreans are always cool even if they don't run right. :)

Walt Tampa, FL