Hey guys, so I'm running ms2 on a v3 board fuel only. The car is running beautifully, I couldn't be more happier, however, I have one problem. I am getting battery spikes about once every 30 mins or so. I looked over the wiring and everything looks fine. So am not sure if this is a ms issue or my alternator dieing, the battery is brand new. Im running pwm for the injectors but this was happening with pwm off also. Ms is getting power from a relay which is triggered by the ecu power wire.



here is a log of it
http://ivan300.tripod.com/spike.xls

Could be your wideband heater switching. Mine does it, alot more than that actually. Just a possability depending on where you have the wideband and MS wired.

I have the ms and lc-1 wideband(both heater and system) grounds all grounded to a single point. What can i do to stop this?

prolly nothing. Why are you worried about it? Should not cause any issues. Mine switches very rapidly and it never causes any issues.

its annoying, also can be very violent depending on how hard im accelerating, can this cause any issues while boosting?

also i have voltage correction set to 0.100, with 880cc injectors, if i set this lower then the spike wont affect the pw so much, but how crucial is this setting normally?

This should not be affecting your pulsewidth. You have an issue somewhere. Thats not your Wideband then.

If you have a digital meter, set to record and record the voltage at the battery. Compare the meter to the MS realtime display or datalog.

You may have some sort of ground issue in your MS. You should be grounding your harness right at the battery or the chassis ground right by the battery. You do not want to let the MS case touch the cars chassis either. That has caused ground noise in a few members cars.

Now that you mention that i see in your datalog where it is affecting the other sensors which is affecting your PW. YOu have some sort of ground issue. Open your MS up and see if there is flux all over the board. YOu will see what apears to be a hard clear paste around the solder joints. I saw a few that were made by someone else on this baord and they were not cleaned at all. Flux can cause a lot of issues.

Terry

battery voltage affects pulswidth, that's why there is a voltage correction field in the injector characteristics.

i have all of my ground on one bolt on the chasey right beside the battery. Its not affecting any other sensors, because when the car jerks my foot presses the throttle a bit that's why the rest of them go up and then down.

I will have another look over the board as i did solder it myself.


btw thanks for the help terry. :)

it is affecting the other sensors like coolant ect.

My battery voltage fluctuates all over the 12v range and it does it very fast. MY PW is rock solid so if your statement were true as you put it, my PW should have issues. I have none.

If you dont like the answer, fine. Good luck.

hmm thats odd

from the docs
"Battery Voltage Correction (ms/V) (BatFac) is the number of milliseconds that MS2-Extra (or MicroSquirt Running MS2-Extra) adds to each fuel injection pulse to compensate for the slower opening of the injectors with lower supply voltages. Generally 0.10 ms/V or 0.2 ms/V is about right. "

my voltages are super steady at 13.2-13.5 other than the random spike once in a while

i lowered the correction to 0.050 and its not noticeable anymore, whats your setting and what injectors do you have, remember with bigger injectors a small pulse width makes a big difference.

my batt correction is 0.10 and i have 780cc injectors.