ECU ground or chassis ground?? Calling all electrical whiz-kids!!

[MrBoost]

I had to take my AVC-R out of the car to troubleshoot a problem, and need to wire everything back now.

My questions are, (please see attached pic),

1) Would there be a problem with tying the 2 grounds together and putting that to a chassis ground INSTEAD of tying it to the ECU ground??

2) Why the heck are there 2 ground wires in the first place? What sort of a difference (voltage? potential?) is the AVC-R looking for?

3) Does the AVC-R draw to much current for pin 92 (ground) of the ECU?

I had it hooked up according to the pic before, and everything *seemed* to be working fine, but I ended up shorting out the sensor ground track on my ECU, but I only had the AVC-R and (before DSMLink) the AFC hooked up to the ecu ground (pin 92). I obviously dont want to short out the ground track again....



What do you guys think?

You must be logged in to view this image or video.

 

[SpeedFreak03]

1) Would there be a problem with tying the 2 grounds together and putting that to a chassis ground INSTEAD of tying it to the ECU ground??

Well, for the SAFC (also uses 2 grounds on the ECU), the grounds are used to figure out some voltage, so the SAFC can 'trick" the ECU correctly. I guess its something similar with the AVC-R (maybe for correct RPM reading). So you do need both ECU grounds ON the ECU, I just dont know what they are there for, but I know APEXi uses them for something!

2) Why the heck are there 2 ground wires in the first place? What sort of a difference (voltage? potential?) is the AVC-R looking for?

I really don't know why the AVC-R would need them, but I can understand why the SAFC would. Maybe for RPM?

3) Does the AVC-R draw to much current for pin 92 (ground) of the ECU?

No it shouldn't, I know a few people running the AVC-R and they have no problems like that.

Anyway, MrBoost is right, redturbo, sorry man your wrong. In car electronics, all grounds aren't the same. Why do you think APEXi enginneers put those 2 grounds there? Im sure they had some reason. Why do you think mitsubishi (or any car manufacturer) doesn't just run a 2 gauge wire from the battery to the chassis, and ground everything to the chassis, instead of running ground wires? Now for a house, yea its all the same, but not in a car.

 

[MrBoost]

SpeedFreak03: thanks for the reply.........I really wish I knew what the potential difference between the grounds on the ECU is used for.....does the AVC-R trick the ECU at all?? (by allowing more boost than the stock BCS would??) I know boost is controlled by mechanical means in our cars, but I also know that boost pressure is one of the factors the ECU bases its fuel and timing calcs from...bah, who knows what the heck those kooky APEXi engineers were thinking when they developed the product....

I also wish I knew what the current overload was that happened to fry the ground track leading to the sensor ground (pin 92) of my ECU. Hmmm.........anyone else got any ideas what could have created this?? All I had hooked up was the AVC-R and the AFC.

Well, anyways, I guess I will just end up hooking it up like the manual shows, to ECU ground pin 26, with required spacing, of course.