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The ECU runs the BPC all the time Posted by Ari [Email] ![]() ![]() In Reply to: Re: Are you buying them new or used?, william, Mon, 18 Jul 2005 21:24:25 Members do not see ads below this line. - Help Keep This Site Online - Signup |
It is normal for the ECU to make the BPC 'chatter' all the time. The BPC in '97 (and earlier) has three leads - one is power, and the other two go to the ECU. The ECU pulses both leads, and the ratio of the pulses positions the BPC valve. The valve is not On-Off, but moves continuously. That's normal, and it should buzz when the engine is running.
The ECU has two switches (transistors) that complete the ground connection.
Now, if one of those transistors gets stuck closed, you'll have full current on that leg of the BPC. If that's on the Boost side, you'll get overboost. And the coil in the BPC is designed to be pulsed, not stuck on all the time. That can overheat the coil and kill the BPC.
At this point, I would stop feeding BPCs to a hungry ECU, and check into a used replacement ECU.
posted by 192.249....
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