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Discussion Starter #1
First, the car is a 97, 6spd, single turbo conversion (S360), factory fuel system, tuned to 18lbs (high) and stock (low). S-AFC Neo for fuel management and Greddy BCC.

The MIL trips under heavy load on the high boost setting. Code is p1405. Doesn't trip on low boost. Search results pointed me to the turbo pressure sensor and the BCC tuning tech article.

I tuned the BCC according to the tech article, using a VOM. It's set to 4.1 volts for my application. All the connections are soldered and patched in through a fields harness. The fields and factory harnesses are in good condition with no chafing or loose connections. I'm still getting the MIL on the high boost setting. I am not experiencing fuel cut.

I'm at a loss on the next step of troubleshooting. Any suggestions? I want to call the BCC defective but don't want to throw $ and parts at it w/o a good diagnosis. I assume the BCC acts as a voltage clamp, prohibiting fuel cut. I don't understand why I'm getting the MIL but no fuel cut. Thanks for your time!

Tony
 

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Discussion Starter #3
I did the pin-to-pin tests and everything metered out in spec. I think I found the culprit.. I checked the output voltage of the BCC again and it changed. I readjusted it and put some black putty on the adjustment pot to hold the screw in place. Seems the screw wants to back out. Since I readjusted, no code has popped. Crossing fingers that it worked for good.
 

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Captain Hammer
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One thing we've seen setting any of the BCC's (Greddys or ours) is sometimes using an outside power source gives you a different voltage clamp than what you get on the car, so we now always tune them on the cars battery/electrical system instead of a battery outside of the car. Should not make any difference, but we've seen it pop up enough.
 
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