Flex Fuel Analyzer signal during cranking
 

Is this normal behavior from the FF signal?



ON E85:

https://datazap.me/u/solidone/flex-0...130&mark=44-53


E77:
https://datazap.me/u/solidone/flex-0...&mark=28-35-49


It doesnt effect fuel trims much if I have closer to E85. Although if I'm running closer to E10 it throws the fuel trim off momentarily. Not a huge deal but it would be nice if I can avoid that altogether with a stable signal.

Yrs a lot of flex fuel kits do this as battery volts drops during cranking so does the ethanol signal volts, oft kits seem to be particulary bad but most do it to some degree. it can cuase issues in cold starts as ethanol content drops so does cranking fueling. Ecutek has an ethanol hold feature in coding to sort this but not in openource

You are a gentlemen and a scholar, mate. Now I want Ecutek.. :brokenheart:

You could try say 100 uf capacitor from the signal line to ground that will slow the change in ethanol content. mght need to test some different values


https://www.electronics-tutorials.ws...ntegrator.html

At cranking the voltage goes past 15v from the acc power momentarily, both to the analyzer module and the sensor. I wonder if I limit the voltage power with a resister can stop the signal spike at cranking?


According to this I can limit the input voltage to power under 14V with a couple of resistors. I suppose I can hook up my motorcycle battery to the power for the module and/or the ethanol sensor and see what happens before i go cutting up wires.

just try and stabilise the ethanol sensor signal to ecu at Pin 20 conbector A35 . Not the input volts to system

That's my point in limiting the input voltage. Assuming it is the dip then spike of the input voltage causing the dip and spike in signal output. The signal will not surpass 4.5v, it's held at peak voltage as I see the voltage go past 15v during cranking from the acc power source.



the minor oscillation during operation about 1 or 2% ethanol isn't going to have a negative effect. 1 or 2% change does little to no change in the fueling or ignition timing. Tho if limiting the voltage works, it will only work to eliminate the spike, not the dip.



I haven't done or purchased anything yet. I will get my interpolation tables dialed in before I start cutting wires up.