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1qwkmini

Battery Voltage early Mini Cooper Vipec

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My battery voltage drops to 10.4-10.8 range for a split second and returns to 12+V  when starting my Mini.  Is that unusual and will it cause a problem with the Vipec (Voltage too low).  I've been chasing this problem for a while now.  The car starts fine from a cold start (even with the voltage drop). But has real difficulty refiring if it stalls or starting if the engine is partially warm.   It tends to be easier to refire if I cycle the master power switch off and on again. BTW I know s*^t about setting up this thing (Jan from RMW set it up). I think it's time to find someone local to tune this thing.

ANY THOUGHT/HELP APPRECIATED!

 

 

 

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It's had a few different (known and tested) batteries in it and same thing happens.   I'm working my way thru all possible tests today.

Alternator---I completely disconnected it and same thing. When the car is running I have 14+ V.  I've disconnected all possible high draw accessories with the same result.

What I really need to know is if the momentary drop to 10.5ish Volts will cause a problem for the Vipec----because the car fires up great from a cold start....just not on a refire.  It could be the way the Vipec is setup that is causing the Refire issue...but I need to be sure it's not the voltage causing the issue

Edited by 1qwkmini

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The ecu will not have any issues with the voltage drop on start.

I have seen some cars with alternator issues and the voltage would drop while running on the dyno.  Ecu just did its job and adjusted injector latency and coil dwell values to suit.

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I've gotten past the voltage drop issue...tested everything and I can't find anything causing the drop, so I will assume that this is normal on a Mini Cooper and it doesn't seem to shut down the ECU.

Now another question: On the no start on refire....If I simply turn off the ignition key and try and refire, it simply won't start.  If I however cycle the master power breaker (race car) and try to restart...it fires up just fine (maybe not as nice as from cold).  Is there anything that may be setup on the ignition circuit that isn't getting turned off with the key that could be causing an error with the Vipec??  sensor or something?   It may be something that is getting constant power that needs to be switched power.  Any ideas appreciated.  Could it be the Vipec unit?

Edited by 1qwkmini

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There is ECU hold power function on these ecus since they have E-throttle.  So when you turn the ignition key off normally, the ecu actually stays alive for a little while to reset the throttle motor etc.  If you disconnect master power then you will interrupt that process and not need to wait for the normal time out period for the ECU to shut down by itself.  It sounds like you just need to go back to your tuner and get them to tweak the pre-crank prime or cranking enrichment tables.

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