[DML] Re: The Flickering Tach, High Hunting Idle Challenge

["David Teitelbaum" <jtrealty@xxxxxxxxxxx>]

By changing the charactoristics of the pick-up coil (the resistance
and capacitance) you are dampening the signal which reduces the
fluctuations which is making the ECU respond slower. My guess is
something else is CAUSING the fluctuations that the pick-up is
measuring and sending to the ECU. I would carefully check every
electrical connection and the routing of the wires to try to eliminate
the fluctuations. Some of the wires are routed a certain way to
eliminate (reduce anyway) inductive pickup which would cause
interference. The ECU does not have a high failure rate. The common
sources of problems in the engine electrical control systems are the
pick-up coil and the ignition coil. Of course dirty wiring connections
or a worn-out (or contaminated) O2 sensor is also common. BTW how old
is the O2 sensor? I know the origional was contaminated when the
turbos were removed, they leaked oil badly which would have killed the
sensor. I worked on one car which I was going to bet had a bad ECU. We
swapped it and several other parts and had NO EFFECT!!! The problem
turned out to be VACUUM LEAKS. You really have to start with the
basics. If the engine has a mechanical problem like vacuum leaks, no
amount of fiddling with the control systems is going to "fix" it.
David Teitelbaum
vin 10757


--- In dmcnews@xxxxxxxxxxxxxxx, doctorDHD@xxxx wrote:
> 
> Well I put a scope on the input to the ignition ECU and found that
when I  
> put the 2.2uF cap across the pickup coil it reduces the amplitude a
bit and  
> makes it look smoother.  Again this smoothes out the idle and no 
flickering.
>  
> Now for the next part of the puzzle.  Today I put a 390 ohm resistor
 across 









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