John H

I just got a tuner and currently have the 87 tune loaded. I anticipate finishing off that tank of gas tomorrow and loading one of the higher octane tunes. Question: Is it necessary to pull the fuses for the fuel pump and stuff when just changing tunes, just like it was when I initially installed/used the tuner the first time?

Dysan

I've never pulled any fuses when I've loaded/changed my tunes.

Five Oh Brian

+1 / I've never had to pull fuses when loading or changing my tunes.

CO_VaporGT_09

Who told you to pull the fuses in the first place?

garyb900

NO!!!

mykee

nope dont need too

John H

Wow. Interesting. I read something on the SCT website when I was reading the instructions on how to load a tune. It said something about removing certain fuses that would draw a constant current with the key in the on position. This is all new to me so I didn't know that I didn't need to do that. Now I know. Thanks folks!

Five Oh Brian

I have been told not to have any accessories running while you're loading tunes, so I always make sure everything is off and the door is closed. But, you shouldn't have to pull fuses.

2k7gtcs

theedge67

I think it is just to make sure there is not a drop in voltage during the upload. I have heard of bad things happening when the voltage drops and the tuner quits mid-upload. Like, the tune is corrupted and you can't just start over, and it won't let you continue...you are stuck with a non functioning car.

NotQuik

My diablo for a friends tahoe also mentioned that it was a good idea to pull certain fuses.....so that's not the first time i've read that and to confirm on your original quesion....


No.

WaltM

No. I have loaded tunes several times and have never pulled a fuse. Just keep your accessories off and don't mess with anything while it's loading.

fdjizm

So i shouldn't be turning the headlights on and off, putting the windows up and down, running the radio loud and playing with the turn signals while i load my tune?

05YellowGT

As long as you know you battery is in good condition , I never pull any fuses. Like was said above they don't want any sudden draw on the system dropping the voltage while it's uploading ...

metroplex

It's not necessary, but it drains battery power and it puts unnecessary load on your electrical parts that do stay on during the flash.

In my 2000 Crown vic, flashing the PCM would cause the IAC (idle air bypass valve) and fuel pump to run continuously. The old 9100 blue flasher takes 5 minutes to flash, the newer XCal2 and other devices take about 1 minute to do it.

Also a word to the wise, your alternator will not fully charge the battery. It was not intended for this task, and generally will keep it charged to about 80-90%. I recommend using a battery charger during flashing. It's also a good idea to use a battery maintainer (like a Battery Tender) on the weekends or when you're not using the car. The Tender will keep the battery fully charged.

John H

Good information here. Thanks everyone!

WaltM

Pretty much it.

BEW119

In the SCT book, it refers to pulling the e fan fuse, so they don't come on when uploading. I have never had the fans come on when the engine is off. But I have pulled the fuse on occasion out of fear of not getting a start and a corrupt file.

05YellowGT

You didn't' say what type of tuner you have , but if you have an SCT X3 here's a link to the Brenspeed site. At the bottom of the page is a tunning video showing how to upload a tune. There was a sticky on this before the crash. If you have one of the old X2's there's a video for it to in the tech section ...

http://www.brenspeed.com/3000.html

John H

It is the x3 that I have. Thanks for that link. I'll check it out once I'm able to get on the computer later.