Melvin

About a month ago I started having charging system issues. Started out with not charging at all, then overcharging after doing a few things. Long story short I decided to send my MSPNP2 out to get repaired for fear that my alternator circuit was bad. Additionally around the same time my voltage, IAT, and CLT temp sensors started to feed inaccurate information to me. When my ECU arrived they diagnosed it and found out the alternator circuit was indeed bad, but there was nothing wrong with the temp values/calibrations they measured.

Got my ECU back in the car and everything is still inaccurate, although I will say now the car charges differently at a somewhat more normal value of 13.5V measured with a voltmeter at alt output wire. Headlights and heater does't seem to lower voltage either. It seemed to kind of fix something, but now I'm feeling something deeper into the harness has gotten fried as well. The voltage is still incorrect, as well as both the IAT and CLT sensor. IATs used to read 130 and now read around 120, and CLTs used to read 185 but now read 175. I have a 180 thermostat in there so something is definitely off.

Any thoughts? Could the overcharging (reached 17V a few times) have blown something? Is there some main part that controls voltage, clt, and iat?

Interesting piece of info I found out today while driving the car is sometimes when I'm flooring it all the way to redline it will cut out for a split second and seem to hit a limiter or something. Right after that happens I can look at my CLT temp and it's at what used to be normally 185/186. Then a few seconds after that it goes back to reading 175ish again. I wasn't quick enough to check battery voltage or IAT but it seems like those might be fine too when this happens.

Of note up until I had the charging system issue I had no issues at all, car was normal as can be. Using the same tune that I had a month ago too.

Would love to hear some thoughts.

Thanks

Melvin

Update for anyone that possibly runs into this problem in the future:

Measured sensor input voltage for IAT and CLT. Should have been at or very near 5v but it is 4.6. This is the reason why my temps are scaling down.

This prompted me to think the ECU was getting a bad ground, but up on a voltmeter check and inspection it was fine. Also had cleaned them about a week or so ago and still nothing.

Now I am going to try and follow the 5v line back to the pinout. Based on the diagrams, it comes from pin 3F (on a 1999). Will check that with the ECU ground as negative to see if it still reads 4.6 or if its 5 and I have a drop somewhere.

Just to explain the alt from another perspective the ECU should regulate its voltage somewhere in the 14s, but since something is up it thinks 13.5 is 14.xx .

If it reads 4.6 again at 3F then perhaps the ECU wasn't fully fixed. I'm 99% sure there is an internal voltmeter on the MS. Anyone have any thoughts?

Thanks

gooflophaze

Noticed in some logs MS3 was reading 17-18v's, which turned out to be false from reading my multimeter. NA so no alternator control. Tried fixing a few sensors by rescaling them, yada yada. Also upgraded to a new firmware - and suddenly everything started reading correctly. Don't know if it was a corrupted eeprom or what, but try that.

Melvin

Alright I'll check the firmware. Thanks for the tip

Melvin

Checked the firmware, it was the latest version (3.4.3) and updated tunerstudio software from 3.1.02 to 3.1.03. Checked again and still the same.

Measured IAT and CLT 5v pins from ECU and got 4.65v They were pins 2A (IAT) and 2E(CLT). Think they should be 5v or very close to 5v. Going to email diy again and see what they say.