when getting ready to work on your rig, is so that the computer can reset itself?? I know, I know, there's electrical safety and as a former USAF aircraft mechanic, I thoroughly believe in being SAFE. So, if I'm working on electrical circuits or wiring or whatever, if it's electrical, MAKE IT SAFE, I understand that.
What piqued my interest in this was that I just noticed that the first thing they want you to do, no matter what it is that you're getting ready to install, step #1 in every instruction sheet I've gotten/read, from the air box to just today when I installed the MagnaFlow exhaust, step #1 is to DISCONNECT the battery cable. The MagnaFlow directions stated that besides the electrical safety aspect, the computer will reset itself and "notice" the upgrade, in this case, my new exhaust system. O.K. I guess that makes sense. Next time I do any upgrading step #1 will be to remove power from the vehicle to be safe....I mean so the computer can reset itself!!
I wonder how many of those upgrades that were installed by part time mechanics like myself, failed to work because the mechanic didn't disconnect the battery so the computer could "notice" the upgrade, like it states in the instructions?? Can that happen??

 

CYA. Companies don't want to get sued when your trucks runs over you when you short out the starter contacts with the wrench or wrist watch. Sure as heck someone would sue because they didn't make any installation as "idiot proof" as they could have.

 

FWIW , your computer is NOT going to "notice" a new exhaust , or an intake.

Dis-connecting the battery is in the instuctions for safety reasons only, as stated , so you can't sue someone when your working on your truck and it runs you over , or takes out the door on your shop , or the neighbours kid riding his bike past your house...

 

....or so the wife doesn't jump in it to run to the store while you're still under it.......

And most importantly........to keep your buddy from blowing the air horns while your hands are deep in the engine bay trying to reach that ratzafratzin' release latch on that daggum sensor plug so he can watch you hit your head on the hood just for kicks....

 

Ahhhhh.......That explains that big knot on your head

 

Oh, so that was YOU........ that also explains that big grin on your face........

 

LOL, as I just found out, even something as simple as changing filters can expose you to shorting out the starter.......

Computers? There only for those guys with too many valves........

 

"FWIW , your computer is NOT going to "notice" a new exhaust , or an intake."


I think that statement's wrong.....
You mean the ECM (Engine Control Module or "computer") won't adjust or even notice the increased air flow from say a new air intake?? Granted, an exhaust system doesn't do much performance wise or even increase the airflow out that much but you're telling me that the computer doesn't make adjustments for increased air flow say from a new high performance air intake??
I'm no Ace mechanic but I think that increased air flow IS recognized by the computer and minuscule adjustments are made constantly by the computer many times per minute depending on many different conditions happening both in and outside of the motor.

 

I think it depends on the actual vehicle. I have noticed a difference on many vehicles after disconnecting the battery EVEN WITHOUT MAKING ANY CHANGES. On most newer GM vehicles after you disconnect the battery the car/truck seems to run very bad untill it has been driven a while. I would think ANY change would be noticed even just putting in a new stock air filter.

A friend was a mechanic for Nissan and he has done some "tuneups" on cars just by resetting the computer and driving the car agressively after it was connected. It sure seemed to make a difference.

On DC products I don't know but I would think the same would apply (but not on my '95).

 

Depends on what you're doing. Sometimes they say to disconnect the battery even when you're working inside the cab because you might accidentally set off the airbag sensors, knocking you out... Is there any problem to just disconnecting the main pos. cable from the driver's side battery instead of the neg. cable? It's a lot easier to just disconnect the pos.

 

Disconnect ground first because... you can hit a lot more things working on the ground and not cause a problem. If you touch the body with the wrench you're using to remove the positive cable... big sparks fly!

 

"I think that statement's wrong....."
No, he is right. ISB's dont have an O2 sensor or a spark plug to monitor what is going on during and after combustion, they only monitor conditions before combustion. They don't have a learning capability, it just runs a program. unhooking the battery will do nothing more than erase codes and radio stations.

But, like say a high flow air filter and exhaust are added, it will start the fueling curve sooner because it sees boost sooner. All it knows is X amount of boost + X amount of throttle position + X amount of RPM = X amount of fuel + X amount of timing. Basically.

My 12 valve will do the same thing with its mechanical "program". It doesn't re-learn any thing by disconnecting the batterys.

-Kevin

 

I spit up a little coffee there...

 

My buddy was installing gauges in his truck. He was drilling something, I guess he went through the fuse box lid or something...started up the truck and it plowed forward into his trailer and the trailer into the wall of his shop. I don't know how he did it. :lol: