well after 16 years my optima 25 finally failed. I looked through the threads but did not see anything about maintaining the control unit memory while replacing. Do I need to plug a battery into the cigar lighter to maintain while changing?
changing the battery
- Thread starter dr914
- Start date
It's not that big of a deal to "lose" the memory UNLESS you need to smog the car shortly after battery replacement. Replacing the battery will cause all of the monitors to be reset and you'll need to go through some drive cycles to get them "set" again.
However, the OEM charger or an aftermarket float charger connected to the the cig lighter should be sufficient to retain the ECU's memory as it is direct-wired and not ignition-switch wired.
However, the OEM charger or an aftermarket float charger connected to the the cig lighter should be sufficient to retain the ECU's memory as it is direct-wired and not ignition-switch wired.
Howard
GT Owner
Careful there. Most battery maintainers need to "see" a threshold battery voltage or they will shut down.
viva gt
GT Owner
Like one of these??
Powerbuilt 648539 Computer Memory Keeper : Amazon.ca: Electronics
Powerbuilt 648539 Computer Memory Keeper : Amazon.ca: Electronics
www.amazon.ca
twobjshelbys
GT Owner
I posted this somewhere before, probably in one of the battery topics.
Plugging the Ford supplied tender into the charging port inside the passenger compartment worked for me. I put an OBDII reader and read the system readiness status before and after and everything stayed.
However, be VERY careful about the positive battery cable! Take it off and wrap it completely in electrical tape. You don't want it short against a ground and it is highly likely during the changing process that it will!!!
I don't know if 9V is enough to keep the system alive.
Plugging the Ford supplied tender into the charging port inside the passenger compartment worked for me. I put an OBDII reader and read the system readiness status before and after and everything stayed.
However, be VERY careful about the positive battery cable! Take it off and wrap it completely in electrical tape. You don't want it short against a ground and it is highly likely during the changing process that it will!!!
I don't know if 9V is enough to keep the system alive.
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That's a very good point! The OEM Ford GT is a "dumb" charger just blindly supplying 500mA, so it will work. But, smarter float chargers may not work as you accurately point out.
There is NO known cause of the gauge failures. One theory is electrical, another is corrosion of the fine needle movement with needle "stickiness" often being a predecessor to failure.
GT monitors can often be reset within 50 miles - but only if you really know the drive cycle.
Evap monitor setting requires a specific amount of fuel in the tank and also needs to have a temperature differential. As such, it can be a little tricky to get it to set.... and some areas (California included) will now allow Evap monitor not to be set.
HighHP
GT Owner
I don't try to keep the memory alive. I guess results here prove me wrong, but battery chargers provide dirty voltage, without being tied to a battery to stabilize. This has the potential to ruin electronics. Some electronics specifically mention...do not use with battery charger..even WHEN connected to a battery. Also, when tying a small battery into the system, bad things can inadvertanty happen. So....unless keeping the memory alive is absolutely critical, the risk of damage is very costly.
I bet "Analogdesigner" has some thoughts on this, and probably has hooked an oscilloscope to a battery charger...any comments from "analogdesigner"?
I bet "Analogdesigner" has some thoughts on this, and probably has hooked an oscilloscope to a battery charger...any comments from "analogdesigner"?
twobjshelbys
GT Owner
Way less than $200. Bluetooth OBDII reader from Amazon was under $20. Free Torque app on android phone (app lists compatible readers.)
twobjshelbys
GT Owner
I'm also an "analog designer"... I would assert that most of this is "old wives tale"... The primary reason is that virtually ALL electronics are on the "other side" of the ignition switch... There are some, but very few, things that are alive when the key is off, the OBDII memory being one. And there is really no reason for that given that the info COULD be stored in flash memory...
HighHP
GT Owner
I had additional needs for my scan tool, hence the expanded budget range. Buy what you want.
gtjoey
Keep Smiling - GT Owner
- Oct 14, 2005
- 3,454
I used the 9volt saver for My Vanquish where seats, windows, mirrors and f1 clutch relearn is saved.
There is nothing like that in the GT.
Drive it for a bit and the car recycles by itself.
Just a great car.'
MAKE SURE YOUCLEAN THE GROUND AND BOLT AND THREAD.
HIGHHP The gage comment was if the battery was flat along the way or low and surges the gages which will blow them out....
GTJOEY1314
There is nothing like that in the GT.
Drive it for a bit and the car recycles by itself.
Just a great car.'
MAKE SURE YOUCLEAN THE GROUND AND BOLT AND THREAD.
HIGHHP The gage comment was if the battery was flat along the way or low and surges the gages which will blow them out....
GTJOEY1314
Indy GT
Yea, I got one...too
Joey, not to point out the obvious but a Ford GT is not an Aston Martin.
I would certainly rely on Kendal’s (nota4re) recommendations. He works on the GT and knows the systems.
I would certainly rely on Kendal’s (nota4re) recommendations. He works on the GT and knows the systems.
so battery replacement went very easily. Bought the Optima Redtop 25 at oreilly's auto parts for 91 bucks, had it in stock, put heavy blankets over the fenders, carefully removed the trunk lining, plugged in my 12 volt power source into the cigar lighter, removed the negative cable first, then the positive, rested the positive in the heavy blanket, unscrewed the battery clamp, pulled the battery up and out at an angle, pealed off the optima sticker, put a hair dryer on the ford gt battery sticker and pealed off, stuck the old sticker on the new battery and carefully reinstalled everything. Car fired up immediately with no glitches. Stuck the optima sticker on the old battery and got my 18 dollar core charge back.
Best thing is that the original battery lasted 14 years! (too bad the hood and hatch shocks do not!
Best thing is that the original battery lasted 14 years! (too bad the hood and hatch shocks do not!