Turbo problems

[Chad]

I've seen this happen a couple of times, both times I was either messing 
with the O2 sensor signal or the MAP sensor.  I noticed that the ecu's I 
was working with would use the last cruise conditions to determine the next 
idle conditions.  If I would cause the O2 sensor to read too lean at cruise 
(fooling the ecu to run richer), the next idle would be filthy rich.  Same 
case for a MAP sensor I was playing with, except in reverse, it would use 
the last idle as the next cruise conditions.  Maybe you're seeing signs of 
a worn out O2 sensor?


>I have a question regarding a BOSCH Digifant car that I have 
>turbo'd.  Upon startup the car idles fine. Regular O2 based AFR meter 
>rapidly cycles from rich to lean and everything seems normal. After the 
>car warmed up I took it out and tried some hard acceleration runs. Car 
>behaved pretty well, that is didn't see any rich or lean spots that were 
>worrisome. After 5-6 pulls I let the car idle down to cool the turbo. At 
>this point the car started running real rich, (Blowing black smoke) and 
>rough. I pulled the plugs and they were completely black. I am running 
>Bosch Platinum WD-6 plugs.
>My question is: Do you think this is a problem with the EFI set-up or is 
>something wrong with the car (ie sensor bad, bad coil or plugs?)
>I understand that once the plugs start to foul then the condition is just 
>going to get worse and worse in a never ending loop.
>Is this something that I could remedy by changing the heat range on the plugs?
>Thanks in advance for any info.
>Justin

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