strange battery fluctuation and drop at high rpm

[swifty35]

since i installed the ms3x using the ms3x both full harnesses i realised that the voltage gauge on tunerstudio is showing the battery voltage at idle fluctuates sometimes between 13.4- 14.5v and also the other main issue is under acceleration above 6000 rpm full throttle passes the voltage starts to drop from 14v to low as 11.4v. so far i changed to an upgraded bigger alternator, using a bigger alternator charging wire over factory size going too my power distribution block, added bigger ground wires to engine and battery and issue still remains. Only thing that is still oem that the ms3x gets its battery power from is the main relay that i have not changed out.

the way how i have the power wired is battery is in the trunk using a 1 gauge power wire goes through a 150 amp fuse then to the distribution block and my main relay is receiving its battery power from the distribution block not directly on the battery.

a log is added below this is a night time pass with headlamp on

[Matt Cramer]

Where is the MS3 grounded?

[swifty35]

All the ms3 grounds are grounded to the engine head

[Matt Cramer]

Try grounding it to the battery instead.

[swifty35]

Both harnesses grounds or just the main harness grounds

[swifty35]

So I ran a ground wire from battery to the ms3 both harness grounds and still no luck same fluctuations at idle, I also tried wiring in a new main relay with the battery power directly to the relay instead of getting the battery power from the power distribution block

[swifty35]

I tried running a wire from direct + battery to ms3 red power wire to also try eliminating the main relay and still the same issue with fluctuations at idle. I had never had this issue with my ms1 wired into my factory car harness only thing I have done I'm useing the ms3x assembled v3.57 from diy and the ms3x full harnesses and this issue start occurring is it possible that something inside the ecu could cause my voltage issue?

[Matt Cramer]

Are you using high or low impedance injectors?

[swifty35]

I'm useing high impedance ID injectors, useing batch fire injection and coil on plug wasted spark (crank sensor only)

[swifty35]

so without any feed back recently i managed to try a brand new ms3x (without knock module,and has 2bar internal sensor) in my car and the voltage looks alot smoother cruising on the highway, i'm only able to load up an idle logs the cruising are to long but could email them if needed.

my ms3x is v3.57 from diy with internal knock module and 4 bar map daddy installed by them.
my fiends new ms3x is also v3.57 from diy without knock module and stock internal 2 bar sensor.

what with in my ecu could be faulty causing these fluctuations?

[swifty35]

So no input on my issue?

[billr]

I don't have any good suggestions, but don't want to leave you feeling ignored.

Is the experiment with your MS and your friend's "repeatable", have you tried each several times now? Are they running the same firmware and MSQ?

I don't suppose either of you are eager to swap the MS3, to see if the problem stays with the mainboard or follows the MS3; but that is what I would try if the option was available. At least, remove your MS3 and then re-install it to re-seat the 40-pin contacts.

Have you contacted DIY's customer service directly?

This may take a lot of tedious monitoring with a voltmeter. It looks like the voltage swings are fairly regular/repeatable, so at least you have a chance...

[swifty35]

Yip switched between the 2 for at least 2 days. Unfortunately he is looking to install his in his car at the moment so won't be able to switch main boards but yip both had my same firmware and map