Has anyone had this happen?

**TA98** · 12-02-2009, 10:30 AM

I have an Optima Red Top battery that i swapped with the standard style battery in my car. The optima is 800cca and the old one is 525cca. When i put the optima in the it idled a little erratic for a couple of seconds which i assumed was just the computer readjusting itself. But then it continued to idle almost 1000 rpm higher even after it had warmed up. If I hit the gas it holds that rpm for about ten seconds before slowly dropping down. If I put it in gear then pop it in neutral it revs up to 3000 rpm. It pulled itself up to 3rd gear without ever thouching the pedal I put the old battery in and everything thing is normal. Have you ever heard of this happening? Or why this would happen?

**2001NBMZ28** · 12-02-2009, 10:47 AM

It's normal for the idle to be erratic after a battery is disconnected/reconnected. Did you give it a few ignition cycles so the PCM could relearn the idle? BTW 525 CCA is too low, my helms says it should be at least 690.

**TA98** · 12-02-2009, 11:40 AM

Yea i shut it off and started it a few times. And thats just the battery that was in it when i bought the car.

**DaddySS** · 12-02-2009, 01:46 PM

I would check the optima with a volt meter. It sounds tsrange and of course the only explanation I can think of is over voltage.

**TA98** · 12-02-2009, 05:42 PM

I did and its the same as the battery i had in it before. It acts like a vacuum leak but once i switch it back everything is fine. Im gonna take it to the shop i used to work at and have it tested tomorrow i think

**0rion** · 12-02-2009, 06:33 PM

give it time to adjust......

**TA98** · 12-02-2009, 06:43 PM

how long do you think

**JaycenK** · 12-03-2009, 12:22 PM

you need to put road miles on it. Most do little odd things untill you get some miles on it. 30 min of all around driving should do it.

**TA98** · 12-03-2009, 12:47 PM

When in put it into reverse it bounces the rear. And its hard as hell to stop because in drive it doesnt want to go below 2000 rpm.

**JaycenK** · 12-03-2009, 12:50 PM

OK thats not normal, check for hang ups around the TB

**TA98** · 12-03-2009, 12:52 PM

i have. but as soon as the old battery is back in its fine.

**JaycenK** · 12-03-2009, 12:57 PM

you sure you put a multimeter on that thing to make sure it's making only 12 to 13 volts?

**JaycenK** · 12-03-2009, 12:58 PM

it sounds like it's putting out 18 to 24

**TA98** · 12-03-2009, 01:04 PM

a hair over 10 volts, i just went and checked it

**JaycenK** · 12-03-2009, 01:12 PM

Possitve to pos and negitive to neg right? hum

**cammed goat** · 12-03-2009, 01:16 PM

This is a first for me. When I used to install batteries in 4th gens they never idled high. When I put my red top in my car, the car was smooth. This is interesting.

**ntimid8r** · 12-03-2009, 01:30 PM

Originally Posted by T/A98

a hair over 10 volts, i just went and checked it

That's WAY low. Too low to start a car. Double check your voltage measurement. Are you using an actual multimeter or looking at the car's gauge display?

**TA98** · 12-03-2009, 01:38 PM

actual multimeter. Its been in my garage for a month or so. It cranked a little slow at first then fired up and cranked fine after that.

**ntimid8r** · 12-03-2009, 01:41 PM

What's the voltage when the car is running? Should be around 13v while running. But from how you've described the issue with idle and all....makes me think the throttle body linkage might be binding or dirty, or perhaps the maf sensor is dirty and not reading the intake air correctly. May want to check those items for condition.

**JaycenK** · 12-03-2009, 02:35 PM

He said it is fine once he puts the old bat back in though. It's like it has a bad cell or something that is causeing the alt to have to change the amount of load it puts out. But that souldn't change the engine speed right? It's done through the regulator. Alts run full load all the time and the regulator changes the load the electrical system see's. The PCM can't change engine speed for more amps from the alt can it?