ALWAYS... ALWAYS... ALWAYS... unhook the NEGATIVE battery cable first. There's not conflicting story on this, this is how it is and is basic Mechanics 101. There are two reasons for this:

1) If you are wrenching on the positive terminal and happen to bump the body or any other metal part of the vehicle or engine, you have an instant arc welder. Since nearly every car manufactured today is "negative ground", meaning that the the negative battery terminal is attached to the body, frame, and engine, if you were to accidentally short your wrench while undoing the negative cable, nothing will happen. If you short across the battery terminals... well, it wouldn't matter which side you are working at that point. :yikes2:

2) If you remove the positive battery cable and it should happen to touch the negative battery terminal or body, there is a chance that you could cause a sudden capacitive discharge in any of the onboard electronics which could damage them.

After removing the NEGATIVE battery cable, many people say to turn on the headlight switch in order to induce a drain to discharge any residual stored voltage in any of the electronics, including the PCM. Since in most cases there is already about 300-500 mA of current draw on the vehicle's systems, not to mention additional load from the dome lamps (if the doors are still open) and the hood lamp (if it's not broken), turning on the headlights won't hurt but probably isn't necessary. I've always let it sit 10-15 minutes, but seriously doubt anything over 30 seconds is necessary. Considering that the KAM (Keep Alive Memory) is akin to the memory presets of your radio, you'll find out in short order how long it takes to clear the PCM.

Hope this helps.

Thats what I knew also (always negative first). I am glad you clarified for those who may be unsure because there are posts on other forums telling people to unhook positive and/or negative and I wanted to make sure if it was just negative or both posts.

I did the mod today and everything turned out great. Noticed a nice bump in throttle response. Great mod IMO!

-Lynn

Glad you liked the mod, Lynn. I'm not really sure I can feel any big change, but it was sure fun to do. And, it SEEMS like it should do better at high RPMs. :shrug:

I saw a post in another forum that talked about touching the positive cable to the negative post. It gave me a "queasy" feeling, but I couldn't really see any super harm. I DO like Bill's opinion though. From personal testing, there's a lot of things sucking current all the time, so very soon after you disconnect the negative cable, the whole system is going to be dead.

And, boy; if you should happen to touch a ground while unscrewing the positive terminal (with the negative still connected), the number of amps that would suddenly try to go through your wrench would probably light up a whole city! OK, not quite, but the spark and heat would be pretty scary!

- Jack

Once, I accidentally dropped a wrench across the batter terminals. It sparked and popped for a second till it welded to the terminals and literally meted the end of the wrench off, along with the battery terminals. It doesn't take much to melt lead.

Scared the begeezus out of me. Just luck the battery didn't explode (which I've had happen before, too). Nasty stuff... :yikes2:

Whenever I work on batteries I use a clean rag or shop towel and cover the opposite terminal. Cheap insurance! I also use plastic coated wrenches but rag works the best!

Depending on what vehicle you are working on, watch out and understand mfgs tsb and/or service proceedures on batteries. Some of the newer vehicles won't start until a code is entered into the radio or via a scan tool, after working on the battery.
Also follow Bill's post #131 in this thread.
Lars

That's a great tip about covering the other terminal, Lars! :thumbs up yellow:

Interesting about no-start conditions in some vehicles.

- Jack

I always use a fender cover now. Covers the battery and keeps the truck from getting scratched. It's a win-win!

Well, I cleaned my throttle body, went with a k&n and did the intake mod all in the same day so for me I did notice quite an improvment. Now I need something else to keep me busy with my truck without spending alot of money! I heard about the TPS mod/adjustment, any thoughts?

-Lynn

Quick question about the mod. :idea: I did this mod about 3 weeks ago, but I never un-hooked the negative terminal to reset the computer.:doh: By now has the computer learned to run with the extra air, or would it be in my best interest to reset the computer? :shrug: Thanks for any help!

Don't bother with the battery. There's really no reason to mess with it when doing the snorkel mod. All that's really happening is that the modest restriction is being alleviated allowing a little more flow at higher RPM. However, this mod DOES NOT AFFECT the Mass Airflow Sensor and doesn't significantly change AFR like a CAI does. The MAF sensor still accurately reflects the airflow into the engine and the computer handles everything from there.