Lost Tune After Pulling Battery

[mic0r]

I drive an R32 GTS-T with the stock ECU and an SAFC2.

Recently, I got new suspension installed and the workshop had to disconnect my battery due to disconnecting the stereo (mounted on the back of the rear seats).

I'm wondering if the previous dyno tune I had has now been thrown out the window. The reason I ask is my fuel economy has now gone to hell, and all the benefits of the tune are gone.

If i get a remap done to the stock ECU - will pulling the battery cause the same thing to happen? Does this also occur with aftermarket ECU's like the PowerFC etc.

[QWK32]

you shouldn't have lost the tune on the safc, unless the unit is faulty. aftermarket ecu's and remapped ecu's also wont loose there tune when disconnected from the battery.

[mic0r]

Yeah, I don't think the SAFC2 has lost it's settings. What I think has happened is that when the battery has been disconnected and then reconnected, the ECU has started learning again, but because it's also getting information from the ECU it isn't learning correctly?

Can anyone shed some light on this?

Sorry if I'm not being clear :<

[PM-R33]

Nope that can't happen. Battery disconnection doesn't affect anything.

[Munkyb0y]

you can take a tuned ecu/piggyback and sit it on a shelf for years. it will still retain all its settings.

if they shorted it out, then maybe the unit is now faulty?

Edited March 15, 2009 by Munkyb0y

[2LV8ETR]

They use an EPROM.

In short, the EPROM is a memory part which will not forget its program or data when power is removed.

Very similar to your ECU. It still retains the normal engine management functions after disconnection of the power source.

[Don Dada]

The safc2 will not lose its settings when the batt is disconnected.

However when the ecu is reset by removing the battery it does "learn" a different setting with the changed air flow voltage it gets from the safc.

I've experimented with this in my car so let me explain a litle more....

When u install the safc once u've raised boost etc. and the ecu goes into rich &retard mode and u tune the safc, the ecu learns this tune in its "protection" mode or what ever u want to call it.

When u now reset the ecu with this same setting on the safc ,the ecu no longer goes into "protection" mode because u have leaned out or decreased the voltage the ecu sees, so what now happens is the ecu now tends to advance the timing a little too much and afrs tend to go a little more lean as well so u start to got knock.

So what i normally do is get a basic tune to get rid of r&r as much as possible, reset the ecu and then fine tune the safc again to get the best results.

Now this refers to the rb25det, and as far as i know the rb20det does not have r&r protection... so i was merely using this as an example to show that it is possible for the ecu to learn a different setting with the changed airflow voltage from the safc when it is reset.

Is this the first time since the safc was tuned that u have taken off the batt pole?

U could probably try resetting it again. Or put a wideband on it and see whats going on......

Rb ecus are weird

[SECURITY]

read through the SAFC2 manual and figure out how to switch between file 1 and file 2. file 1 should be your tune and file 2 should be a cleared map with no adjustments or vise versa, it doesnt matter which way it is - just dont delete it accidently.

switch to the file with no settings then reset the ECU again and go for a drive.

switch back to file 2 and it should all be back to normal.

[mic0r]

Smell: You hit the nail on the head, and yes - it is the first time the battery has been disconnected since getting the tune.

SECURITY: Thanks for the tip mate, I'll give it a go. Any idea if the SAFC2 manual is online?

[SECURITY]

http://www.apexi-usa.com/support_installation.asp

[mic0r]

I can't read those PDF's... I just get a lot of little dots like its in brail.

Maybe my PDF is rooted here @ work. I'll try again when I get home.

[tridentt150v]

download acrobat reader and install, its free.

[mic0r]

I've got acrobat, just this work PC being a pain in the arse. Thanks mate