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ECM Hack- coolant temp sensor

Started by rug_burn, Wed 12, Mar 2025, 14:08:01

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rug_burn

     Does anybody remember that mod you can do to keep the spark advance  where it should be for performance?     And tell me where to find it?
   This has to do with the the fact that the engine control module (ECM) retards the spark timing between idle and about 3000 rpm once the engine coolant reaches operating temperature.  The idea, IIRC is to add a resistor somewhere, (in parrallel) with the temperature sensor to 'trick' the ECM into leaving the advance set for performance, not easy or conservative riding.    There was one circuit I recall  that had a potentiometer to make it adjustable, and I made a copy of the whole thing, but of course, I can't find it now, years later....
    Some of the old timers here, I'm sure, know what I'm talking about.   
    Thanks-
...insert hip saying here..

HayHauler

VRCC# 28963


98valk

once the engine is at operating temp, it doesn't like all that extra advance 2k rpms and below. the mod provides a 4 extra degrees at 3k rpms where it then goes to zero additional advance.
so a little help for better mpg at 3-33k rpms, little more when using a 4-6 degree TW.

see curve here
https://www.manualslib.com/manual/396434/Dynatek-D3k1-1revd.html?page=2#manual
1998 Std/Tourer, 2007 DR200SE, 1981 CB900C  10speed
1973 Duster 340 4-speed rare A/C, 2001 F250 4x4 7.3L, 6sp

"Our Constitution was made only for a Moral and Religious people. It is wholly inadequate to the goverment of any other."
John Adams 10/11/1798

rug_burn

Thank you very much, gentlemen... that's what I was looking for.
...insert hip saying here..