New battery

[Lemay88]

Bonjour Viper owners,

I just changed my battery yesterday (old one was 7 years old).
Pretty simple job if you have a good set of ratchet (how many different screws can someone use...lol).
I am wondering if a new battery can change any “performance” on a Viper.
I noticed my idle is more stable (less lumpy) and feel the car is a little more responsive to throttle input.
Is it my imagination or it is possible.

Thanks

Ben

[dave6666]

You dumped all the adaptives when you changed the battery. It may or may not revert to the previous state after the LTFTs rebuild.

[Lemay88]

May I ask what are the adaptives and LTFTs??

I keep the tender on while changing the battery....was that wrong??

[dave6666]

Adaptives are the Long Term Fuel Trims. When you dump them as is likely when changing a battery, even with a tender on as the tender likely did nothing as it really isn't a power supply if it isn't detecting a load, the base fuel tables are rebuilt upon and suplemented by the Short Term Fuel Trims - STFTs, what the O2 sensors are reading - and once the STFTs accumulate enough repetitive readings, the LTFTs are developed and become part of the base fuel tables. When you change a battery you typically dump the LTFTs and start over which reverts back to the virgin base fuel tables.

Base table + STFTs -->> LTFTs

LTFTs + base table -->> extended "learning" and running of engine

As an example, if the base fuel tables which are generic (to the Viper) tables meant to run the engine result in a lean condition as read by the O2 sensors, the STFTs will be reading the lean condition and tell the PCM to be adding fuel to compensate. Once it has done that long enough the LTFTs will be developed and added to the base table making the added fuel permanent. At least until different readings are accumulated that would mean the LTFTs need to be changed, or if you change your battery or flash a new tune etc. Which dumps all the long term fuel trims.

[daveg]

May I ask what are the adaptives ??

Previous learned values.

and LTFTs??

Long term fuel trim. In short, LTFT's are learned over time. The S(short)TFT are used to just make small adjustments to the air fuel ratio in real time.

[BLRDViper]

Lemay, my input is a little Old School regarding new batteries. When you buy a new battery off the shelf it is most probably no where near full charge. If you put it in a daily driver, within a few days the normal driving/running will bring it up to where it needs to be. When you put it in a car that gets limited use, it may never get fully charged and it's life cycle will be shorter than normal.
So, first thing I would do is get a charger on the battery and bring it up to full charge, and then keep a battery maintainer on it when the car is sitting idle.
Congrats on the new battery.
BLRD

[AviP]

So you're a virgin again and have a steep learning curve.

[gfviperman]

The two best things you can ever do to older cars are new tires and new battery ....

Brings them back to life!!!

[Steve-Indy]

Good answers above...keeping in mind that fully charging the battery, and a few spirited drives should cure most of the above issues.

You can also try an ignition on, engine off throttle relearn. To do this, turn ignition to run but do not start car. Slowly depress gas pedal fully and release...do this twice, again noting that the motor must NOT be running. This MAY help matters on your next drive.

[Lemay88]

Thanks a lot for posting all those usefull informations and mostly thanks for educating me...again.

Just so you guys know, even after 5 years of ownership, I still get the same grin on my face every time I go for a ride in my Viper and am still scared of all this power and torque...great american built car

[AviP]

Just so you guys know, even after 5 years of ownership, I still get the same grin on my face every time I go for a ride in my Viper and am still scared of all this power and torque...great american built car

22 years and that feeling hasn't changed. I bought mine Memorial weekend in 97.

[ocmiteddy]

Thanks a lot for posting all those usefull informations and mostly thanks for educating me...again.

Just so you guys know, even after 5 years of ownership, I still get the same grin on my face every time I go for a ride in my Viper and am still scared of all this power and torque...great american built car

I have the feeling when people stop feeling that, is the same time their car becomes a tree hugger

[GregM]

Interesting thread. I recently changed my battery as well but car mostly sits. I actually drove her 76 miles today. Yes, shocking. Weather was beautiful and took it to work. Anyway seemed to run smoother on way there and on way back a little rougher, I may try Steve’s procedure...

[Old Surfer]

Man, looks like you pulled the nose pretty close to that curb.

[Matt Dillon]

Old Surfer I thought the same thing, not to mention taking up a 2/3 car parking space! Where I live that's a BIG No No, cause you're just asking for somebody to key your car! JMO