Battery Disconnect - ZR-1 Net Registry Forums

Perry Mitchell · 04-04-2021

I have read that disconnecting the battery for storage, the ECU will loose all it's tuning memory and that a low fused power wire should be installed to prevent this from happening.. I know the radio presets and the clock will be lost but what about the ECU? Also, would this be true for my '84 Corvette?

HAWAIIZR-1 · 04-04-2021

I have been doing this since 2003 on my C4 Zs and never had an issue of tuning memory loss; only clock/radio presets.

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Paul Workman · 04-09-2021

Perry, you may be thinking of clearing the codes stored in the ECM when disconnecting the battery. The calibration tables are not affected by disconnecting the battery. In fact, IIRC several places in the factory service manual (FSM) refers to disconnecting the battery for various reasons involving repair OR clearing old codes stored in memory.

For example, sometimes the FSM directs you to disconnect the battery to clear the (old) stored codes so that if a particular code reappears, you know it was logged after the battery was reconnected and not before.

Perry Mitchell · 04-10-2021

Thank you for the replies. Paul, what you said is true but I wonder why some car makers say to connect another power source to the car when replacing batteries. Is it to simply keep the radio and clock working? I know my 84 Corvette runs like poo after disconnecting the battery for a time until I take it for a drive to what I thought was to get the ECU back on line.

Corvette95 · 04-10-2021

The thing about battery disconnects and why I don't use them is the a//c programmer. This is just my opinion, but if you disconnect your battery, make sure your temperature is set to default 75 (this is good for storage as well to prevent blend door from sticking to the side of the heater box). Especially on the 90, it can take several minutes for the blend door to re-calibrate and sometime is fails. GM updated the 90 programmer for this very reason.

XfireZ51 · 04-11-2021

I typically disconnect (-) batt cable during the winter. What happens w fueling is that your BLMs get reset to 128. As u drive the car, you will eventually get back to the level of tune you were at b4 pulling the batt cable.

Dynomite · 04-11-2021

I use the Battery Disconnect Switch on everything including Corvettes even if I only park them for a few days

The Battery Disconnect Switch TIPS

Tractors, ATVs, Corvettes, Trucks, cars start up even over winter as if starting with a new battery.

The Battery Disconnect Switch also acts as a great theft deterrent

Perry Mitchell · 04-12-2021

Quote:

Originally Posted by XfireZ51

I typically disconnect (-) batt cable during the winter. What happens w fueling is that your BLMs get reset to 128. As u drive the car, you will eventually get back to the level of tune you were at b4 pulling the batt cable.

Thank you. Finally an explanation that makes sense to me.

04-04-2021	#1
Perry Mitchell Join Date: Nov 2018 Location: Washington Posts: 98	Battery Disconnect I have read that disconnecting the battery for storage, the ECU will loose all it's tuning memory and that a low fused power wire should be installed to prevent this from happening.. I know the radio presets and the clock will be lost but what about the ECU? Also, would this be true for my '84 Corvette?

04-04-2021	#2
HAWAIIZR-1 Join Date: May 2010 Location: Japan Posts: 3,582	Re: Battery Disconnect I have been doing this since 2003 on my C4 Zs and never had an issue of tuning memory loss; only clock/radio presets. Sent from my iPhone using ZR-1 Net Registry __________________ Craig "ZR-1 NO KA 'OI" "ZR-1 ICHIBAN" 1995 #228 Black/Black with Dunn Heads ZR-1 owner since September 2003 ZR-1 Net Registry Founding Member #0074 NCM Lifetime Member #2048

04-09-2021	#3
Paul Workman Join Date: Nov 2007 Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri Posts: 6,493	Re: Battery Disconnect Perry, you may be thinking of clearing the codes stored in the ECM when disconnecting the battery. The calibration tables are not affected by disconnecting the battery. In fact, IIRC several places in the factory service manual (FSM) refers to disconnecting the battery for various reasons involving repair OR clearing old codes stored in memory. For example, sometimes the FSM directs you to disconnect the battery to clear the (old) stored codes so that if a particular code reappears, you know it was logged after the battery was reconnected and not before. __________________ Good carz, good food, good friendz = the best of timez! 90 #1202 "FBI" top end ported & relieved Cam timing by "Pete the Greek" Sans secondaries Chip & dyno tuning by Haibeck Automotive SW headers, X-pipe, MF muffs Former Secretary, ZR-1 Net Registry

04-10-2021	#4
Perry Mitchell Join Date: Nov 2018 Location: Washington Posts: 98	Re: Battery Disconnect Thank you for the replies. Paul, what you said is true but I wonder why some car makers say to connect another power source to the car when replacing batteries. Is it to simply keep the radio and clock working? I know my 84 Corvette runs like poo after disconnecting the battery for a time until I take it for a drive to what I thought was to get the ECU back on line.

04-10-2021	#5
Corvette95 Join Date: Jan 2006 Location: Decatur, AL Posts: 1,119	Re: Battery Disconnect The thing about battery disconnects and why I don't use them is the a//c programmer. This is just my opinion, but if you disconnect your battery, make sure your temperature is set to default 75 (this is good for storage as well to prevent blend door from sticking to the side of the heater box). Especially on the 90, it can take several minutes for the blend door to re-calibrate and sometime is fails. GM updated the 90 programmer for this very reason. __________________ Corvette95 Registry and Forum (*************) 1989 C4 Conv Wht/Gry Auto Hardtop Top Flight SOLD 1995 C4 Coupe Purple/Blk 6 Speed 1989 C4 Conv Wht/Red Auto SOLD 1996 C4 Conv Black/Tan Auto SOLD 1994 C4 Coupe Wht/Blk SOLD 1995 C4 ZR-1 White/Gry #278 Dual Dunn Head SOLD 1986 C4 Coupe Black/Red 4+3 SOLD 1990 C4 ZR-1 Red/Red #0454

04-11-2021	#6
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,708	Re: Battery Disconnect I typically disconnect (-) batt cable during the winter. What happens w fueling is that your BLMs get reset to 128. As u drive the car, you will eventually get back to the level of tune you were at b4 pulling the batt cable. __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX

04-11-2021	#7
Dynomite Join Date: Aug 2009 Location: South Dakota/California Posts: 3,797	Re: Battery Disconnect I use the Battery Disconnect Switch on everything including Corvettes even if I only park them for a few days The Battery Disconnect Switch TIPS Tractors, ATVs, Corvettes, Trucks, cars start up even over winter as if starting with a new battery. The Battery Disconnect Switch also acts as a great theft deterrent __________________ Left Clickable links -Solutions- LT5 Modifications/Rebuild Tricks Low Mileage ZR-1 Restoration 1990 Corvette (L98) Modifications LT5 Eliminated Systems LT5 Added Systems LT5/ZR-1 Fluids 1995 LT5 SPECIFIC TOP END REBUILD TRICKS Last edited by Dynomite; 04-11-2021 at 04:16 PM.