View unanswered posts | View active topics It is currently Sun Nov 29, 2020 12:20 am



Reply to topic  [ 34 posts ]  Go to page Previous  1, 2, 3, 4
Separating the power and signal grounds on a V3 board 
Author Message
TO220 - Visibile

Joined: Thu Mar 28, 2013 6:53 pm
Posts: 14
Ok so I have been doing tons of reading and am quite angry at the moment considering the $430 dollars I spent on this MS2 V3.0 board.

I have been having running issues from the get go. The car runs but not great. After research I found that people would install a cap either in the bootloader(h1) or from center of Q3 to Q9 to fix the battv spikes i was seeing. So I did this and everything seemed normal except that my VR input was noisy at times. So I just recently purchased the BrickRPM from Fred. After installing it in the car it ran great, no jittery timing very smooth all around. Next day horrible resets and rpm spikes all over. Also if i turn on my Knock settings the car will not even idle.

I am running single coil ignition/distributor using the built in driver and low impedance 440cc supra injectors. I believe this to be(after much reading) the source of all my problems since people are seeing the ground plane actually rise up by 2v. The situation is probably made worse because I am using the megasquirt relay board.

Here is my plan A...

1. Ditch the relay board
2. Use separate ground return for Ignition Driver(Q16) and Injector PWM drivers (Q3 and Q11)(not sure what else to add).

Plan B...

1. Ditch the V3.0 and relay board to some poor soul
2. try to get as much as I can for number 1
3. Buy v3.57 and rewire my engine harness


Sat Apr 20, 2013 5:49 am
Profile
Moderator
User avatar

Joined: Tue Jan 15, 2008 2:31 pm
Posts: 15371
Location: Home sweet home!
OK, calm down, firstly! :-) Secondly, you've put up enough info to fix the setup. MS2 + V3.0 is still the preferred MS setup if you must MS at all.

Plan A, B, and C:

1. Ditch the relay board ( agreed! :-) )
2. Use an ignitor in the engine bay to switch your coil! Putting direct coil control in the ECU is ASKING for trouble unless both the ECU designer and the ECU installer know exactly what they're doing. In cars ONLY BMW do this. Some bikes do it too. 99% of OEM cars do NOT do this. Nor should you.
3. Your injectors are low Z, so, move to Jean's P&H board (it's not expensive) and again, put it in the engine bay. OEMs that used low-Z injectors pretty much always used resistor boxes for them, so they weren't really P&H at all. Modern DI and diesel stuff uses a driver box, you guessed it, in the engine bay.
4. 3.57 boards have many of the same issues, some new different issues, and some fixes, stick with 3.0...
5. Ensure that none of the wiring in the coil loop or injector loop goes anywhere near your RPM signals or ECU/other sensors. Ensure that both loops are as short and direct as possible. Run only lowish level signals to those loops from your controller. When I say loop I mean [battery NEG >> ignitor >> coil >> relay >> fuse >> battery POS], same for low Z injectors, but replace "ignitor" with "P&H box".

In summary, while it is possible to put ignition coil drivers and PWM P&H drivers in your ECU in the cabin of your car, and generate a radio transmitter in the process, alerting aliens of our existence, it's certainly not recommended, not a good idea, requires careful *everything* and generally isn't something that you should consider without a BE in electrical.

Rather than "just get a P&H box" you could split your grounds and keep them inside, up to you. It's more work, and your loom will be critical too. Definitely get rid of the ignition control, though. And drive the ignitor properly too, or use logic level coils. For more info on "properly", hit me up on skype.

Hope that helps!

Fred.

PS, WTF am I do giving MS support again? I hope Bruce and Al and James and Ken all die in slow-smoldering fires :-)
PPS, MS3-pro has no low-Z support and no on-board ignition, they're learning slowly, only took them 10 years. Less features == more, in this case.

_________________
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Sat Apr 20, 2013 10:22 am
Profile WWW
TO220 - Visibile

Joined: Thu Mar 28, 2013 6:53 pm
Posts: 14
Thanks for all the support. I am actually finishing up my computer engineering degree in the next couple of weeks :)
I will be ordering the 12' db37 wiring harness along with connectors and fuse blocks from diyautotune. I think I may just run resistors on my injectors but I've been searching and can't seem to find the optimal current they should run at so I can choose an optimal resistor to match.

I've got a pretty busy week lots of projects one of which is an assembly program for the s12 microcontroller but I will keep you updated and possibly start a build thread with lots of pictures :)


Sun Apr 21, 2013 10:38 pm
Profile
Moderator
User avatar

Joined: Tue Jan 15, 2008 2:31 pm
Posts: 15371
Location: Home sweet home!
Resistors works. Consider a resistor box from some other old car.

About loom : viewtopic.php?p=11386#p11386

Would love to see a build thread in user'srides :-)

_________________
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Mon Apr 22, 2013 2:29 am
Profile WWW
Display posts from previous:  Sort by  
Reply to topic   [ 34 posts ]  Go to page Previous  1, 2, 3, 4

Who is online

Users browsing this forum: No registered users and 4 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group
Designed by ST Software for PTF. ColorizeIt.