Stall after battery replacement
 

Hi all

have 2000 Silvie, 5.3L

2 yo Duralast battery died on me overnight. Confirmed bad by Autozone tester and replaced pro-rated under warranty.

I installed new battery, truck cranks and starts right away - then dies the very moment I let go off gas pedal. Same repeats for few more start ups. I revved engine a little bit, then held pedal at about 700rpms, and idle slowly restored itself. Took me about 5 heart breaking minutes to get there.
Took truck for a spin, did well, except that tachometer usually sits at 500 rpms with D engaged, and truck not moving, now it'll dip down to 400 or so. Did not stall anymore, just that little stumble.

No error codes.

Will poorly charged battery do this? At no point did battery light come up, and voltmeter shows 14.2V charge. As usual. I am charging battery as I type.

Nothing else was touched, straight battery swap out job.

I am not worried yet, but am more curious - why?

Some of the electronics might have lost their mind from the batt dying. Dont panic,drive it for a few days if it dont"relearn" then panic.

some vehicles have a certain proceedure that should be done so the ecu communicates correctly.
I wonder if your truck needs that proceedure.
the few I know of say you have to do some stuff with turning the key, lock doors, roll down window etc etc in a certain rder to reset programming or something.
maybe that is something you can look into

I hope I found the answer:

Stalls or Idles High or Low After Dead or New Battery

Engine idle is necessary for proper vehicle operation; it allows the engine to operate at the lowest RPM level possible without your foot on the gas pedal. At idle, your engine produces the least amount of emissions than in any other time it is operation. Even when your key is in the off position the vehicle still utilizes electrical power from the battery. The amount of electrical power used is a very small amount; the battery can sustain this usage for many weeks. But, when electrical power is completely removed from the system the natural memory is erased. This natural memory is a result of an accumulative data that has been processed and learned by the PCM. One of the natural memory events is the engine idle speed. When the car battery is dead or replaced this natural engine idle speed is lost. After the battery is replaced or charged the engine idle will need to re-learn itself, this is normal. In some instances this re-learn procedure is un-noticeable while others are quite noticeable. During the idle-relearn period the engine will stall when in idle mode, but it is not unheard of too idle to high also. If you have replaced or charged your car battery and now the engine is stalling at idle, or idling to high or low follow the idle relearn guide below.

Step 1: Engine idle low or stall: Once the new battery is installed or charged start the engine. When the engine try's to stall hold your foot on the gas pedal just a little to aid the idle speed. You will need to continue doing this until the engine is warm. When the engine is at operating temperature the basic engine idle setting will engage, the engine should re-gain idle properties. If the engine is still not responding a short drive is sometimes required, both feet will be used to perform this procedure. Put one foot on the throttle and the other on the brake pedal. Continue this until basic engine idle is achieved

Step 2: Engine idle to high: Once the new battery is installed or charged start the engine. Start the engine and allow to warm up to operating temperature. As the engine warms the engine idle should return to normal. If the engine does not return to idle a short drive will be needed. (Note: if engine idle is extreme do not attempt this step). Drive the car until normal engine speed is engaged.

I think, 1st time I swapped battery and had none of this, was because I bought battery BEFORE swap and had it installed right away. ECU prolly had residual memory.
This time, I had battery out, drove around for about 3 hrs, before I placed new one in.
I'll know later today, after hrs. battery's still charging.

Thats a whole lot of words to say what I said in one sentence. But if you drove it for three hours without a batt. you might have screwed up a lot of electronics. Good luck.

assumptions.. drove my spare car for 3 hrs, with battery in the trunk. shopping. so truck was sitting with no battery, resting.
truck's doing fine. was truck day today, started and drove just as usual.

I've seen people run without batteries before, why? Well, they get a jump form someone since they cannot afford a battery. I'd use caution running without a battery as it works as a "filter" surge protector (electrical) ect.

I swapped out a battery in my van and it screwed up the whole EPA emissions test. THe guy told me I should run it 200 miles (said my van needed more miles than most) and the engine will relearn how to do things. Bottom line, I'll have to take the EPA test again in a year because of it. Screw California, the test ain't free.