Stock fuel injection / 034 EFI

JShadzi at JShadzi at
Wed Jun 12 19:56:01 EDT 2002

>> Well, you can adjust the open loop fuel enrichment gain across the board
>> based on coolant temp.  The limitation you might be thinking of is the fact
>> that 034 does not go closed loop until X seconds (configurable) regardless of
>> if the engine is warm or cold.
>I'm thinking more of the fact that it takes a lot of extra fuel to make
>an infernal combustion engine run properly when it is cold, as in very
>cold, as Zsolt said, -40 cold... or at least, say 0 degrees F.  if the
>open loop enrichment you speak of has that range covered, I stand

Yes, of course, what would a fuel system be without ability to control cold start!  The system will add extra duty cycle on cold start up (temp configurable), then there is a matrix based on water temp to compensate for hot or cold engine temps.  Yes, -40F is covered, no problem.  My car literally starts after about 1 second of cranking.  As Marc points out, closed loop programming can be held off for x seconds so as the closed loop programming does not interfere (or try to lean out) the overly rich cold start mixture.  Realistically, if closed loop programming is correct (meaning that the actual fuel mixture is altered minimally by the closed loop becuase the open loop map is proper), there should be no noticeable effect whether the engine is hot or cold.  Marc just got his car running, but as he tweeks it over time, he'll find that he can get very good performance regardless of when the closed loop programming is enacted.  In my car, I have it go into closed loop after about 10 seconds.

>I still think the lack of feedback control on the idle speed is an
>oversight that should be corrected.

Well, if the CIS system is maintained, the stock ISV system should work no problem (which is really what the system was designed for anyway initially).  Now, the Aux air valve also works quite well for cold starting and warm idling, the only problem with the air valve is when I have the lights on and the rad. fan simultaneously.  I've considered adding a small air valve to open when the radiator goes on to correct this.

The next version of 034 will have an additional driver for ISV, however, or an additional driver can be purchased for about $200 that can be programmed to control idle settings.  Problem is, adding ISV control required another driver, and that "drives" up cost too, not just the ISV  =)


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