My 2002 P71 had the original Motorcraft battery in it. While it was still starting the car and passing a load test, I could tell it wasn't the 750 CCA's it once was. That, plus wintertime in Nebraska, plus I found a good deal on an Optima Redtop. So I upgraded.
The car now NOTICEABLY runs better when cold. It ran fine before, and once up to temp it's actually about the same. But first thing in the morning it is so much smoother. How/Why?
Did you clean your terminals of corrosion when putting the redtop on? Thus improving your grounds?
Other than that you got me. I know Jeeps tend to be very symbiotic in their battery/running performance. The way their wired a dead battery will cause the truck to stop running even after a jump. Dunno about P71's though.
Maybe since the Alternator isn't having to charge as much, the engine has less load? Which equals more power? Odd situation indeed.
You will have cleared the adaptive memory from the computer, and if the adaptation was wrong due to a sensor being out of range, so running on the base map makes the car run better.
You cleaned the main EFI ground at the battery, which was corroded and causing trouble.
You spent some money, and your subconscious is justifying it.
You had a split vacuum hose, and when the new battery went it, it crimped off the vacuum leak.
The new battery has too much power, so the Zombies don't use your car on their overnight brain hunts.
I think #1 is probably best.
I will go with better connection and less charging equals slightly less engine load. Maybe due to poor connections you were not getting good signal from all of your sensors and now you have a computer getting what it needs to do its job.
Maybe, like how it runs better after you wash it... your brain is augmenting your car.
this is not in my head. It's flat out smoother when cold. by a lot. I always chaulked up all the interior reverb to my aftermarket exhaust, but that's nearly gone now.
Better spark at startup due to the stronger battery. You're not using up all the power available during cranking so the alternator doesn't have to work as hard keeping the car running.
I only say this because on the electronic heavy Rovers I work on I can sometimes get one with a bad battery to crank but not start-the battery uses all it has to turn the starter but there is no spark. A new battery solves the problem.
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