LT5 ECM Tuning thread

[tpepmeie]

Tyler,
It is a multiplier used to cut the fuel pulsewidth in half when the second set of injectors is active. For example, say you have an base pulsewidth of 10 milliseconds when the engine is running on only the 8 primary injectors. When the ECM commands the secondary throttles open, there is a very slight delay (0.3 sec) then the secondary injectors are energized, and the NEW pulsewidth is now 10ms x 0.51 = 5.1ms. Of course, since it is being delivered with twice the number of injectors, the overall fuel injected is the same as before the port throttles opened.

Increasing this multiplier would have the effect of adding fuel when the secondary injectors are energized. If it were, say, .75, then you would end up with 2 injectors x 10ms x .75 multiplier = 15ms total fuel delivered. This could be used as a band-aid to increase fueling if the injectors are too small or the VE table is not correct. However, I would think the transition would be terrible, and you'd end up with a surge due to the sudden enrichment.

just my $0.02.

Todd