FreeEMS Issues - Firmware
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0000869FirmwareGeneral Featurespublic2013-10-07 17:512013-10-16 09:37
pjohns30 
Fred 
nonefeaturesometimes
assignedopen 
0.2.0-SNAPSHOT 
ASAP 
5697a1f
Improvement
medium
0000869: Priming pulse timing.
The priming pulse happens before the fuel rail gets much pressure in it, so you don't get much fuel. I suggested a delay, but Fred says he doesn't want to wait 0.5 sec to start cranking the engine. So my next suggestion is to inject the priming pulse on the first primaryISR event, or the third, or whatever makes Fred happy.
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Notes
(0002718)
Fred   
2013-10-07 17:54   
I like your idea about doing it on the first hit. The only down side to this is that we'll also prime on a restart without key off, which may then be too much fuel if things are already wet from just stalling, for eg. Let's bang up a thread (can you?) in the firmware section about priming pulse semantics framing it how it is, and proposing your solution, and see what the others think. Link it in IRC once ready. Cheers! :-)
(0002719)
pjohns30   
2013-10-07 18:51   
No you could just make a flag that won't allow it to reprime until it's cleared by the ecu getting reset.
(0002720)
Fred   
2013-10-07 19:17   
Yes, obviously, or a heuristic to deliver less fuel in those circumstances, etc.
(0002730)
Fred   
2013-10-16 09:37   
Added some details.

Changed always to sometimes because this is not demonstrable on most vehicles where pressure is maintained indefinitely. I expect a lot of imperfect modified cars in future, so this is a good request.

Link to Peter's thread: http://forum.diyefi.org/viewtopic.php?f=8&t=2310 [^]