View Single Post
Old 04-03-2012, 12:09 PM   #10 (permalink)
steffen707
Master EcoModder
 
Join Date: Oct 2009
Location: Midwest
Posts: 337
Thanks: 4
Thanked 37 Times in 21 Posts
Quote:
Originally Posted by HAHA View Post
Another factor as the voltage drops is that the ECU adjusts the fuel injector timing to compensate. This may affect efficiency and also the calibration for Scangauge or similar systems. I tried to find out once if Scangauge did calculate fuel correctly based on injector timing. I think it may do so but I'm not 100% sure.

Since you are dealing with rather small differences here, you may have to perform a dedicated experiment to quantify these effects. If your instrumentation calculates correctly when the ECU/injectors run on low voltage, it gets easier. Then you only need to find out if the engine works better or worse with normal/low voltage. If there is a degradation, you may be able to find a workaround, eg. extra batteries to keep voltage up.

At least some of your test runs indicate that your engine may degrade with lower voltage.
Well I don't use scanguage because the d15z1 and civic VX are obd1, so i'm using mpguino.

I would have to do long term testing if what you think might happen is true, that the injectors fire slower, or the ecu compensates on the injector pulse width.

I don't see how my test results indicated degradation though, because in every test I got better gas mileage with the alternator off.
  Reply With Quote