So...if the battery dies

In light of some posts recently, I almost don't feel like posting this. My batteries fine, but when I don't drive for awhile, it's a little slow to turn over. I'll be getting a tender soon, or just drive more. My question, if the battery dies, do you have to let the car idle for 5 mins or until the fans come on? Or can you just start it and go? What if you jumpstart it??? Wait 5 minutes after the jumpstart??? Thanks guys.......Lou

 

If the battery dies and you re-charge or jump start it............you have to let the car idle for 15 mins without touching the accelerator pedal Lou.

Just fire her up and walk away for 15 mins.

 

Question - do you only let it idle for 15 minutes if completely dead?? My assumption always was you only let it run when you change batteries or your battery hits the 0 charge mark??

 

I dont really understand your question Rod?

If my battery goes flat, I charge her up and then start her letting her run for 15 mins without touching anything.

IF I decide to jump start it, then I still let her run for 15 mins without touching anything.

If she cranks sluggish, but starts ok.........then I dont worry about it and I drive off without any issues.

 

And what happens if you jumpstart it, then drive away? Any damage? Should you then later disconnect the battery and reconnect and run for 15 mins? Really have no idea....thanks why I'm asking......Lou

 

Lol, funny you mention it Lou.

I jump started mine a few weeks ago to take a visiting friend for a drive.

The only issue you have by not letting it idle for 15 mins without touching anything is the idle. My car was idling around 1200 rpm and sometimes would drop to around 700 rpm because I jump started the car and drove it straight away.

After the drive, I came home and disconnected the battery. Re-connected it and started her up to let her run for 15 mins. I didnt touch anything and after the 15 mins was up, everything is fine.

So no damage and no worries.

 

Jumpstarting a Ferrari is more of an issue on airbag versions than it is on pre-airbag models because the jumpstart/dead-battery is associated with many fried airbag computers.

In general, a jump-start is very hard on the alternator. Recharging or replacing the battery is a superior option.

On the 348, a dead battery from any cause means that your Motronic engine computers (ECUs) have lost their memory of how your engine performs. These engine computers then revert back to the factory "guess" of how your fuel-air is supposed to look.

Over time, your Motronic engine computers will re-learn your engine in its current state of wear, properly adjusting fuel-air straight away.

You can speed up the "over time" part by starting your motor cold and not touching the throttle until after the cooling fans turn on. However, simply driving your 348 for a long enough time frame will achieve the same result. Might take 300 miles, though.

 

This is excellent information to know.

 

I didn't know the difference between a header and a cat before I bought my 355.

Now I just troll along to gain knowledge.

Learn somethin' new e'ery day on here, I reckon...

 

One very small additional point. Make sure ALL electrical systems (e.g., climate control, radio, radar detector, lights, etc.) are off during the 15 min Motronic re-learn period.

 

Thanks guys. I knew you'd have the answers. Good info........Lou

 

300 miles?

Wow, I didn't realize it was that far. That may take up an entire Sunday afternoon...

Kai

 

... what a waste of time.

 

I have routinely disconneced the battery if I am not going to drive for 7 days or more. I have never let it run the suggested 15 minutes and have never had any problems. It always starts up immediately and idles and drives just fine.

 

Quite interesting.

I always let my car run for 15 mins before I drive it (when battery goes flat of course) except for the other day and she behaved like a spoil little mistress!

 

I thought it best to warm the car before driving it anyway, because the clearances are so tight on these engines. Is that wrong? I'm not sure I understand why you'd need to let engine idle for extended period after jump start. Won't the alternator charge the battery even when you drive it? I think the idea is that you need to recharge the battery but why can't that happen while driving instead of idling? Generally, I thought prolonged idling resulted in carbon buildup and was bad because the oil pressure isn't very high. I certainly agree it's better to use a tender and not get into that situation in the first place.

 

Thanks PAP.

Excellent post!

 

Ah, too easy my friend!

 

So that is why my AirBag light is on after I jumped the car!! Should I even ask what it will cost to fix?

 

Sorry...

 

No, it has nothing to do with this. Once the battery becomes fully discharged the Motronic ECU(s) loose basic start-up parameters. Thus, you need to start the car (with ALL electrical systems off) and allow it to idle (not touching accelerator pedal) for approximately 15 min to allow the ECU(s) to re-learn the parameters.

 

My car is a 1994 348 spider with the Bosch Motronic 2.7 ECU. I have jump started the car, disconnected and reconnected the battery, etc. with no alternator or other issues whatsoever. Just reconnect the battery & drive off, no learning period, etc. Car runs just fine from the git go.

Is the "relearn period" an issue only with the Bosch Motronic 3.5 ECU?

Bonnieboy
1978 308 GTB & 1994 348 Spider.

 

Both 2.5 and 2.7 have learning periods and yes your car could run just fine after the battery was disconnected. Eventually the ECU's will fine adjust to optimize the air/gas mix but until the cycle ends, your car could run rich or lean.

 

I drained my battery because of letting the door open and the red door light kept burning...

A trickle charger is not helping.
Is my battery dead? Or will it "revive" when jump starting?

 

Do not jump. Ferrari electronics not robust and can cause other issues like air bag light. Disconnect battery and charge then reconnect