DIY MS3x hitting limiter 2000 rpm?
 

Hey all, first off I'd like to apologize for my frequent noob post in this MS section.

The issue I am having is around roughly 2300rpm my car is hitting some sort of rev limiter. This happens both in gear and in neutral.

I have loaded the trubokitty 1.6 basemap onto the car with some slight modifications to the VE table. Since installing my ms I have yet to have the car fully functioning. But all sensors have been calibrated and base timing has been set. The car runs some rich but other than that will start and idle fine. Initially I thought this was some sort of fueling issue since the car would start to lean out in this area (2300rpm) but after adding lots of fuel to this portion of the table I am able to see a significant change in the AFR reading but no change in my problem. I have looked through the tune and haven't found any sort of limiter or fuel cut that is turned on... I remember reading somewhere someone having a similar issue that turned out to be the vr conditioner pots. Tonight I reset both r11 and r56, after spinning both pots the number of turns trubokitty has documented. I tested both with a voltmeter. R56 was at 2.7v measuring off of r54. R11 at 2.4v measuring from the zc testpoint. After this the car started and ran as it did previously. I've been pretty stuck on this for a few days now. What further troubleshooting steps can I take?

Some info on the car.
1993 1.6, 2.5" exhaust. no cat
oem injectors, oem fuel pump
vTPS from MK Turbo
DIY MS3x 1.4.1 firmware

Here a short video of what I am experiencing. I added a bunch of fuel in some cells to keep the car from going lean at this rpm.
https://www.youtube.com/watch?v=d8Ja...ature=youtu.be

I have also attached my current tune, a composite log, and normal data log taken in neutral in my garage.

Definitely a rev limiter function. Is launch control activating? CLT-based limiter?

There is no fuel cut in the log. I don't know what spark cut would look like in a log but spark advance is functioning as expected.

Not 100% sure how to check if launch control is activating? CLT based limiter is off. Hard rev limit set to 7200

I am assuming an NA alternator, I have never seen a battery voltage log look like that before. Did you actually measure the battery voltage and calibrate the MS3? It almost looks like there is an overvoltage protection device kicking in or something.

Status2 would indicate spark cut.

This is 100% not spark or fuel cut.

Yes NA alternator from rock auto. I did not measure battery voltage, brand new battery within the last week. Not sure what you mean by calibrating the ms3 for the battery? So no I did not do that.

You better measure that voltage. You could be in the process of killing your MS

yikes. are you saying just measuring voltage directly off of the battery?

while running, yes. measuring at the MS or the alternator would probably be better. Don't rev it anymore until you get this part confirmed.

will do. thanks for the heads up

I had a bad alternator from the parts store, Bosch I believe, that went to 18v when revved. Only ran it a few minutes before figuring out from seriously bright headlights.

While running I measured 14.4v off of the battery with my meter. Voltage does not increase with rpm or anything like that. In the log it shows a constant 14.4v. What should it be looking like?

Does the voltage change when you turn the heater fan on full and the headlights on? IIRC, your idle is high, like 1100, so you may be at an rpm where the alternator voltage is up. I characterized a few NA alternators in detail, and they all had voltages in the 12 range at idle, and rarely hit 14.4. There was also quite a bit of variation in the battery voltage in the log.

NA alternators don't usually regulate that well, especially at idle. I know nothing about the circuitry in your MS, but if there is a voltage limiting device that shunts current to ground, it will conduct current until the alternator voltage drops. They aren't designed to do that normally, only under fault conditions, so they burn up eventually. You can browse around here a bit and see examples of where people have done that.

there may be nothing wrong with your setup, just trying to keep you from bad things if there is.

Just went out and checked, voltage remains the same with heater on full and headlights on. Correct my idle is high around 1100. Looking at my log posted above named "garage" I am seeing a constant 14.4v in megalog viewer. I'm not really sure where you are seeing variation? I am fairly new to MS and tuning, I appreciate your concern to keep me from causing damage to my stuff.
https://cimg9.ibsrv.net/gimg/www.mia...c4abdcf261.png

The point is that there is no variation. There should be. The voltage should drop when you turn the headlights on.

Make sure the 2 pin connector going to the alternator is connected, if it is, tou might want to pull the alternator and get it tested.

Here's another one of home boy's logs from a different thread. Minimal fluctuation but there is some. Still weirdly consistent.

So if the battery is staying at 14.5v all the time wouldn't that entail that the alternator is preforming exactly as it should? I'm not tying to question anybody's wisdom, just trying to understand why this could be a issue.