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Old 02-13-2020, 07:33 PM
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wpoll wpoll is offline
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Quote:
Originally Posted by Clavurion View Post
… If you have normal voltage on the engine bay jump start point BST is OK.
Maybe.... but not always.

BSTs can "soft-fail" where they have enough of a connection for the low current draw (like from a multi-meter) to still allow full voltage to be apparent but when you draw a large current, the voltage loss at the BST become significant and the car won't start. The BST has in effect become a high-resistance joint.

I doubt this is the issue in this case though, as with a high-resistance BST the engine would likely try to turn over but not. Also the electrical load of simply turning on the ignition would pull the apparent terminal voltage down a lot too.

Which reminds me - we've seen a few high-resistance joints at the B+ terminal on the front bulkhead too - I guess this is another possibility? Not sure it matches the symptoms though - sounds more like an EWS issue.
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