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Topic: Post Battery Change Engine Operation (Read 4 times) previous topic - next topic
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Post Battery Change Engine Operation
Yahoo Message Number: 88220
One last note on battery changing. When you change the truck (as opposed to coach) battery, the engine management system must "relearn its idle and fuel trim strategy for optimum driveability and performance" per my 2003 Ford owner's manual.

It then goes on to explain how to do this, which involves operating the engine in a specific sequence of modes for specified periods of time. If you change your truck battery it would be a good idea to look up these instructions and follow them.

Also, while there is nothing similar to do with regard to the transmission it also goes into learning mode for a couple of hundred miles and shifting may be somewhat affected during that period.

Terry

2003 26.5' RB
Gardnerville, NV
Terry
2003 26.5'RB
Gardnerville, NV
Re: Post Battery Change Engine Operation
Reply #1 –
Yahoo Message Number: 88225
tlburnes  wrote: "When you change the truck(as opposed to coach) battery, the engine management system must "relearn its idle and fuel trim strategy for optimum driveability and performance" per my 2003 Ford owner's manual.

It then goes on to explain how to do this, which involves operating the engine in a specific sequence of modes for specified periods of time. If you change your truck battery it would be a good idea to look up these instructions and follow them." --- Terry, do you know what effect, if any, the engine management system's "learning curve" would have on the operation and settings of the ScanGaugeII?

Joan
2003 TK has a new home
Re: Post Battery Change Engine Operation
Reply #2 –
Yahoo Message Number: 88226
Quote
One last note on battery changing. When you change the truck (as opposed to coach) battery, the engine management system must "relearn its idle and fuel trim strategy for optimum driveability and performance" per my 2003 Ford owner's manual.
The last Cyberguys catalog I go had a neat solution to this problem that I'm going to order as soon as we get home with the new rig. It looks like a cig lighter plug with a pigtail for a 9v battery on the end. I assume the plug body bumps the DC up to 12v. You just plug it into the dash before disconnecting the starting battery. It provides the necessary power to maintain the clock, radio settings, computer diagnostics setting etc until the battery is put back on line.

Here's a link to one source:
 http://www.autosportcatalog.com/index.cfm?fa=p&pid=52&cid=41

but you can find others by googling "auto memory maintainer". Less than $20 and worth it to avoid the other aggravations IMHO.

George (flying out on Monday to pick up "Arby" (our new 2007 RB)
Post Battery Change Engine Operation
Reply #3 –
Yahoo Message Number: 88230
I have a little gadget that has a 9 volt battery and a cigarette lighter plug on it.  Supposed to keep the memory alive while changing the battery.

Dave
2004 PleasureWay TD
Re: Post Battery Change Engine Operation
Reply #4 –
Yahoo Message Number: 88233
Joan,

I'm sorry but I have no knowledge of the Scan Guage. Maybe someone else can respond to your question.

Terry

2003 26.5' RB

Gardnerville, NV 89460
Terry
2003 26.5'RB
Gardnerville, NV
Re: Post Battery Change Engine Operation
Reply #5 –
Yahoo Message Number: 88234
"When you change the truck battery, the engine management system must 'relearn its idle and fuel trim strategy for optimum driveability and performance...' "

:: sigh :: Considering that flash RAM, which remembers its contents without power, is literally a giveaway item these days (ask any recent CES attendee), you'd think it would find its way into automotive computers so they could suffer total amnesia when power was lost for a minute or two. Or maybe it has--you were talking about a 2003 engine (like mine), so maybe the new ones are a bit smarter.
 Seriously, Terry, thanks for the tip--I'm sure this would have caught me unawares the first time I replaced the engine battery.
 You know, it occurs to me that this is one place where a rechargeable powerpack (the kind with a 12V gel battery plus an inverter, tire inflator, flashlight or whatever) might be put to use. Clamp the powerpack's cables onto the battery cables, and then carefully remove the battery cables from the old battery's posts and install the new battery. The powerpack would keep the 12V system alive, so the computer wouldn't forget everything.

Andy Baird http://www.andybaird.com/travels/
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Post Battery Change Engine Operation
Reply #6 –
Yahoo Message Number: 88235
To whomever is interested

FWIW, I had installed a new battery in my '99 LD, and had the battery disconected several other times while I was working on one thing or another. I never took any special steps to reboot the system after reconnecting the battery. Never did I notice any difference in performance or gas milage or anything else afterwards. YMMV.

Tom Johnston, Red '99 TK, Whidbey Is WA,  53 degrees dry but overcast
Re: Post Battery Change Engine Operation
Reply #7 –
Yahoo Message Number: 88236
"I had installed a new battery in my '99 LD, and had the battery disconected several other times while I was working on one thing or another... Never did I notice any difference..."

It's a safe guess that your '99 either lacks an engine computer, or (more likely) doesn't have one that "learns"... so it has nothing to "forget" when 12V power is lost. Count your blessings and be glad you have an older rig. :-)

Andy Baird http://www.andybaird.com/travels/
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Post Battery Change Engine Operation
Reply #8 –
Yahoo Message Number: 88243
Quote
Terry, do you know what effect, if any, the engine management system's "learning curve" would have on the operation and settings of the ScanGaugeII?
I believe that the ScanGauge loses power every time the ignition is off and therefore stores it's configuration and longer term data in a flash memory.  I can't see any reason it would be affected by having the engine battery disconnected.

Art
Art and Barbara
Settled in Atterdag Village of Solvang
2015-2022 fulltime in a 2016 Tiffin Allegro Bus 37AP
2002-2015 2002 LD MB
Art's blog
Re: Post Battery Change Engine Operation
Reply #9 –
Yahoo Message Number: 88248
older_fossil  wrote: I believe that the ScanGauge loses power every time the ignition is off and therefore stores it's configuration and longer term data in a flash memory.  I can't see any reason it would be affected by having the engine battery disconnected.
--- Thanks, Art; that makes sense!

Joan
2003 TK has a new home
Re: Post Battery Change Engine Operation
Reply #10 –
Yahoo Message Number: 88250
"I believe that the ScanGauge loses power every time the ignition is off and therefore stores it's configuration and longer term data in a flash memory."
 Correct. The ScanGaugeII stores all settings in flash RAM, so loss of power has no effect.

Andy Baird http://www.andybaird.com/travels/
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Post Battery Change Engine Operation
Reply #11 –
Yahoo Message Number: 88251
Quote
:: sigh :: Considering that flash RAM, which remembers its contents without power, is literally a giveaway item these days (ask any recent CES attendee), you'd think it would find its way into automotive computers so they could suffer total amnesia when power was lost for
This is simply how you reset the ECU values. It is necessary, since failing sensors, marginal operating conditions, etc, will cause the engine to adjust parameters to compensate and run smoothly. After the problem is corrected, you want to wipe the memory to force the ECU to relearn - and disconnecting the battery is the easy, user-friendly method to accomplish this without specific knowledge. It's not a problem - there is usually a rigorous relearn driving procedure that will expedite filling in the missing values in ECU memory, but just normal driving will do it anyway in a slightly longer period, pretty much transparently to the driver. Just don't schedule an emission test for a few days or so...

Steve
2004 FL
2013 Honda Fit
Re: Hooray George! (Was: Post Battery Change Engine Operation)
Reply #12 –
Yahoo Message Number: 88256
George (flying out on Monday to pick up "Arby" (our new 2007 RB)

 That is EXCITING news!  Hope all goes well and let us know how you're doing.  Where are you headed to after you get Arby?  Would love to see pictures.

Tessa in TX
Re: Post Battery Change Engine Operation
Reply #13 –
Yahoo Message Number: 88263
Quote
This is simply how you reset the ECU values. It is necessary, since failing sensors, marginal operating conditions, etc, will cause the engine to adjust parameters to compensate and run smoothly. After the problem is corrected, you want to wipe the memory to force the ECU to relearn - and disconnecting the battery is the easy, user-friendly method to accomplish this without specific knowledge. It's not a

Steve
Exactly, this is how most all modern vehicles with OBDII function.
Anytime you get a check-engine-light (CEL) that you can't explain away, disconnecting for ~15-20 mins is the easy way to clear the codes. It's also not a bad idea to disconnect in spring and winter to force the computer to recalculate the paramaters when the fuel additives are changed from ethanol to MTBE, as your engine runs differently. Note that OBDII only applies to 1996 and newer vehicles.

Cheers! Adam
Re: Post Battery Change Engine Operation
Reply #14 –
Yahoo Message Number: 88268
wrote: It's also not a bad idea to disconnect in spring and winter to force the computer to recalculate the paramaters when the fuel additives are changed from ethanol to MTBE, as your engine runs differently.
--- Does your state still use MTBE as a gas additive?  MTBE was officially "banned" as a gasoline additive in California in early 2004; every formulation (that I know of, anyway) sold in this state replaced MTBE with a minimum of 10% "corn squeezins' ", i.e., ethanol. ???

Joan
2003 TK has a new home
Re: Post Battery Change Engine Operation
Reply #15 –
Yahoo Message Number: 88304
Before changing the truck battery, couldn't one simply jumper the terminals on the battery isolator (as described in the LD manual), and let the coach batteries keep everything powered for a a few minutes? /noel/
Re: Post Battery Change Engine Operation
Reply #16 –
Yahoo Message Number: 88306
"Before changing the truck battery, couldn't one simply jumper the terminals on the battery isolator (as described in the LD manual), and let the coach batteries keep everything powered for a a few minutes?"

Jeez, why didn't I think of that? You get the prize, Joel, for the simplest, most elegant solution. :-)

Andy Baird http://www.andybaird.com/travels/
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Post Battery Change Engine Operation- Risky!
Reply #17 –
Yahoo Message Number: 88313
Quote
Before changing the truck battery, couldn't one simply jumper the terminals on the battery isolator (as described in the LD manual), and let the coach batteries keep everything powered for a a few minutes?
When you disconnect the chassis battery, you will have the positive cable hanging free, getting bumped and jostled as you muscle the battery out. Should it momentarily touch ground or the ground cable, and if you have jumpered the isolator, you will have the coach batteries attempting to pass several hundred amps thru several runs of
8-gauge wire, bundled with several other cables, and if your LD does
 not actually catch fire it will be because you were lucky enough to have an in-line fuse blow somewhere. Just so you know...

Steve
2004 FL
2013 Honda Fit
Re: Post Battery Change Engine Operation- Risky!
Reply #18 –
Yahoo Message Number: 88315
Quote
When you disconnect the chassis battery, you will have the positive cable hanging free, getting bumped and jostled
Good point, Steve.  It's probably better to either maintain the setting with a 9v battery, or just let the ECU re-learn everything.
/noel/
Re: Post Battery Change Engine Operation- Risky!
Reply #19 –
Yahoo Message Number: 88324
"When you disconnect the chassis battery, you will have the positive cable hanging free, getting bumped and jostled as you muscle the battery out."

That's a good point, Steve--clearly one must be very careful when doing this. But I'm thinking that if you pull a rubber glove over the end of the positive cable, you could probably avoid the risk... yes?

Andy Baird http://www.andybaird.com/travels/
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Post Battery Change Engine Operation- Risky!
Reply #20 –
Yahoo Message Number: 88336
Andy,
 A rubber glove would do, but it would probably be better to *wrap* the bare connector with it, rather than just putting the glove over it. The risk would still be there with thin rubber as used in many disposable gloves. The metal connector, even though insulated, bonking anything else of metal and grounded, could easily penetrate the rubber and cause violent arcing.
 There is another caution when doing this too. Normally one would remove the negative/ground wire from the battery first. This is done as it eliminates the risk of turning a wrench on the positive terminal first, and having that wrench also touch grounded metal!
 So, if jumpering the chassis batter at the isolator, one must be *very* cautious not to touch ground with any metal tool when removing the positive terminal - - even if the negative terminal is removed first, as the positive terminal will remain hot.

bumper Yonder Minden, NV
bumper
"Yonder" '05 MB
"WLDBLU" glider trailer
Re: Post Battery Change Engine Operation- Risky!
Reply #21 –
Yahoo Message Number: 88339
Quote
That's a good point, Steve--clearly one must be very careful when doing this. But I'm thinking that if you pull a rubber glove over the end of the positive cable, you could probably avoid the risk... yes?
Bumper adds another good point - so it's a question of risk management. I think what I would do, if this applied to our LD, is to use a low-ohm resistor with alligator clips as the jumper, and still take precautions. A 5-ohm resistor would only drop the voltage by 2.5V with a 500 mA draw, and allow about 2.4A max to flow if a short occured. A 2W resistor would survive an indefinite short.

Steve
2004 FL
2013 Honda Fit
Post Battery Change Engine Operation- Risky!
Reply #22 –
Yahoo Message Number: 88343
Quote
Bumper adds another good point - so it's a question of risk management. I think what I would do, if this applied to our LD, is to use a low-ohm resistor with alligator clips as the jumper, and still take precautions. A 5-ohm resistor would only drop the voltage by 2.5V with a 500 mA draw, and allow about 2.4A max to flow if a short occured. A 2W resistor would survive an indefinite short.

Steve
Please excuse me and correct me it I'm wrong Steve, but in the case of a short of the positive batter cable, would there not be 2.4 Amps flowing through a 5 ohm resistor? And isn't power consumption equal to I squared R or (I x I x R) or (2.4 x 2.4 x 5) = 29 watts ? In case of an indefinite short would you not need a 30 watt or greater resistor?
 In the event of a direct short of the battery cable I think a 2W resistor would blow like a fuse. In fact, why not just use a fuse in the jumper instead of a resistor? With due caution one shouldn't short the battery cable, but if the worst should happen and it is shorted, you are protected.

Tom
Re: Post Battery Change Engine Operation- Risky!
Reply #23 –
Yahoo Message Number: 88351
"So, if jumpering the chassis batter at the isolator, one must be *very* cautious not to touch ground with any metal tool when removing the positive terminal - - even if the negative terminal is removed first, as the positive terminal will remain hot."
 Good points. Well, perhaps the 9V battery with cigarette lighter plug is a safer way to go. Shouldn't cost more than about three bucks to make one from Radio Shack parts.

Andy Baird http://www.andybaird.com/travels/
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Post Battery Change Engine Operation- Risky!
Reply #24 –
Yahoo Message Number: 88379
Quote
Please excuse me and correct me it I'm wrong Steve, but in the case of a short of the positive batter cable, would there not be 2.4 Amps flowing through a 5 ohm resistor? And isn't power consumption equal to I squared R or (I x I x R) or (2.4 x 2.4 x 5) = 29 watts ? In case
Oops! Absolutely correct, silly mistake. The problem with a fuse, though, is that the instantaneous current before a fuse blows would be very large, and any inductance that spike encounters could generate a dangerously high voltage. The wiring harness should be protected, though. I still like the resistor, but how about 25 ohm, 5W. That will allow a 100mA draw with a 2.5V drop - probably will supply most phantom needs - and although it will get hot with a prolonged short, it should survive.

Steve
2004 FL
2013 Honda Fit