Fuel injection and altitude question
01-26-2010, 11:39 PM
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Fuel injection and altitude question
I figure the map sensor should compensate for changes in altitude, right? How bout a 6000ft diff?
The reason I ask is my 21 super was used at 6500ft (Tahoe) and ran fine with its current cal. The elevations where I boat at range from 780-500ft. The ecu was sent to AZS&M back in 02 when the motor was built (only has 46hrs on it now). I thought about calling them, since I have the Cal# they used- but I've heard the stories....
Just looking for some more info on this... its my first fi boat. I'm planning on doing plug readings this spring, but a wideband o2 looks pretty fool proof- prob end up with a LM2.
Thanks guys!
The reason I ask is my 21 super was used at 6500ft (Tahoe) and ran fine with its current cal. The elevations where I boat at range from 780-500ft. The ecu was sent to AZS&M back in 02 when the motor was built (only has 46hrs on it now). I thought about calling them, since I have the Cal# they used- but I've heard the stories....
Just looking for some more info on this... its my first fi boat. I'm planning on doing plug readings this spring, but a wideband o2 looks pretty fool proof- prob end up with a LM2.
Thanks guys!
Last edited by ndaniels; 01-27-2010 at 10:51 AM. Reason: little more info
01-27-2010, 11:28 AM
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I assume you have a Mefi ecm. Which one?
The altitude compensation can only do what it is told to do by the person that programmed it. It all depends on what was done in the compensation tables as to how well it will perform in lower altitudes. Some spend the time to get them right, some don't. If AZ speed did the programming, then I'm sure the ecm is password protected. That means that no one can even see the cal without the password. The only thing that can be done (without the password) is to erase it and start over.
You will DEFINITELY want to check the engine with a wideband O2 to be sure it is going to run correctly at lower alt. You can burn it down in a few minutes if it isn't right. Good luck with it.
Eddie
The altitude compensation can only do what it is told to do by the person that programmed it. It all depends on what was done in the compensation tables as to how well it will perform in lower altitudes. Some spend the time to get them right, some don't. If AZ speed did the programming, then I'm sure the ecm is password protected. That means that no one can even see the cal without the password. The only thing that can be done (without the password) is to erase it and start over.
You will DEFINITELY want to check the engine with a wideband O2 to be sure it is going to run correctly at lower alt. You can burn it down in a few minutes if it isn't right. Good luck with it.
Eddie
