View unanswered posts | View active topics It is currently Fri Nov 16, 2018 11:29 pm



Reply to topic  [ 22 posts ]  Go to page Previous  1, 2, 3
60-2 sync losses over ≈2k rpm 
Author Message
Moderator
User avatar

Joined: Tue Jan 15, 2008 2:31 pm
Posts: 15194
Location: Home sweet home!
Aside from during interrogation, serial being connected has precisely NO affect on the firmware's behaviour. Therefore you must be introducing some sort of ground or power loop. Are you certain it's sync losses and not something more serious like resets?

To me it sounds like your VR wires are not raw VR wires, and that the minus side is tied into ground in your loom. This may have been necessary with the factory computer due to the circuit they used, however it breaks our circuit so please validate that it's not the case by doing three measurements:

1) minus to plus, ie, sensor resistance
2) minus to ground
3) plus to ground

I'd be very unhappy about having 0 ohms between the engine bay and the max IC. I won't check the datasheet right now, but the max clamp current is available, and you can figure out what resistor is required to produce that max current (or a little less) with 14.4V applied (yielding a difference of 9v DC or so). Going under this is a bad idea.

Progress is good, though. Hopefully you get to the bottom of it with a sensible topology attached at some point.

Fred.

_________________
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 Dec 26, 2015 4:58 am
Profile WWW
Moderator
User avatar

Joined: Tue Jan 15, 2008 2:31 pm
Posts: 15194
Location: Home sweet home!
Please see this post for info on part of the reason why you're having these issues: viewtopic.php?f=56&t=2395&p=42650#p42650

_________________
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!


Sun Sep 04, 2016 10:41 am
Profile WWW
Display posts from previous:  Sort by  
Reply to topic   [ 22 posts ]  Go to page Previous  1, 2, 3

Who is online

Users browsing this forum: No registered users and 1 guest


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:  
cron
Powered by phpBB® Forum Software © phpBB Group
Designed by ST Software for PTF. ColorizeIt.