Computer memory?

[breakawaydaze]

Just recently read a post that mentioned computer memory.  I know most cars have a computer memory that uses the vehicle history, operating conditions, operating temps, fuel burn ratio and a whole bunch of other info to automatically adjust fuel mixture and timing for optimal performance.  I assume that our boat computers follow this process of history management as well.  Now as I think about it, whenever I get done with my boat, I put it on the lift, turn the battery switch off, put the cover on and leave it until next time.  What I am wondering is if my boats computer looses the memory info everytime I turn off the battery.  And 7-10 days later when I get back to it and turn on the battery, the computer starts with zero information.  With zero history info, I wonder if it is hard programmed to run "rich" with conservative timing advance until it can develop some operating history.  It may just be me, but I always feel as though the boat does run richer during the 1st half of the day as compared to the afternoon.  If this is correct, it could be that turning off the battery switch may be causing a bunch of unnecessary recalculations and a rich burn inital operation.  Does anyone know if the Epic computer does have a memory and is it lost when power is cut off?

[HCollado]

Damn Bill...  You are a lot smarter that I thought !!!

You may on to something here as I don't believe there is any battery-back- for the computer.

It will be interesting to hear from Rick on this one.

[HCollado]

Damn Bill...  You are a lot smarter than I thought !!!

You may on to something here as I don't believe there is any battery-back- for the computer.

It will be interesting to hear from Rick on this one.

[wakejunky]

Yes, technically if you turn off the battery switch our engines loose all "memory", but and a big BUT unlike the Lexus ls 400 our engines do not have oxygen sensors so the major sensor the "corrects/ modifies " the basic calibration table is not even used on our engines. with the exception of the coolant temp sensor and maf sensor and baro sensor "built in to the computer" our engines don't adjust from basic calibration tables.
a little info on each "input" sensor

Coolant temp- the Lexus ls400 runs a 180 degree thermostat that helps the car run at our near 200 F. our engines have a 160 degree thermostat which lets our engines run at near 180 F. the reason they did this is for more power. just like many aftermarket "performance" thermostats it never lets the engine reach full operating temp which helps archive a 12.4 to 1 air fuel ratio the known air fuel ratio for making max horsepower. but it makes our engines run a little rich and causes our plugs to foul much faster than normal. back to topic once in OUR operating temp which might take 5 min or less the computer is not adjusting the calibration table any longer

maf sensor - unless its dirty its only adjusting for more air at higher rpm which is in the basic calibration table.

baro sensor- cant find it ? its in the computer and only adjusts for elevation. all fuel injected engines do this nowadays, it eliminates adjusting the fuel mixture like we did on old carburetors

so in the end our engines really don't adjust much or at all from basic calibration tables, so it doesn't matter if we reset the memory every time we store our boats.

[HCollado]

Holy Cow...

Wakejunky, did you take one of these things apart and played with it?

 

[denver]

WakeJunky is absolutely right.  I used to tune cars at a performance shop. Most street cars take 15min of idle and 15min driving to sample and make corrections to the fuel table and idle tables, based on feed back from the O2 sensors (the one before the CAT, the one after it, only turns the check engine light on).  Our boats do not have O2 feed back, so there is not much for it to adjust in the tables! Good thought though!