200 might be sick again, then again.....

[E. Roy Wendell IV]

>
> The potentiometer on the MC2 is only used by the MFI and can be  
> ruled out.
> I have had symptoms like this before in my 200 in moist weather due to
> failing ca5Bp/wires and from bad gas.
>

snip

Not sure I get this...MFI? In any case it's not a potentiometer at  
all even though it looks like one. It's actually an idle switch and a  
full throttle switch in one housing. Common voltage supply on one pin  
and signal out for each switch on the other two. If your idle is  
correct at 800 the idle switch is ok and if you see more than 1.1 bar  
than the full throttle switch is ok. The idle switch tells the idle  
controller and ISV to do its thing and the full throttle switch tells  
the ECU to up the boost via the boost control solenoid and enrich the  
mixture via the mixture control solenoid.

In any case, check engine light without storing of code is a  
sustained knock indication. It may be either real knock or a faulty  
knock sensor signal. Consider cleaning knock sensor connector and  
checking that it is torqued down properly. As this is an MC2 you have  
two sensors.

As always refer to http://www.sjmautotechnik.com/trouble_shooting/ 
trouble.html

Scott has spent untold hours distilling the various Bentley manuals  
into something that is actually readable and combining it with his  
unparalleled practical troubleshooting experience to produce the one  
stop shop for all things turbo CIS related. Let his pain and  
suffering be your salvation.

Roy Wendell
erwendell at mac.com
Too many type 44 tq
A pair of MR2s