full time power source thats easy to tap into?

[RipperXX]

Ok so for the past month I have been trying to find this mysterious vacuum leak. I found some leaks via boost testing and fixed them but it didn't solve my problem, my electric autometer boost/vac (30-0-30) not only read very low vacuum it was not consistent. I narrowed it down I thought to the TB to intake manifold gasket, replaced it and still no improvement.


So today I went to Abel racing and borrowed a mechanical boost/vacuum gauge, unpluged my bov and plugged the line to the back of it and what do you know 19 in/hg even though my electric gauge said only 11 in/hg !!!


So I look on autometers website and noticed it said in there tech area that the red wire has to have consistent dedicated power during the starting process or the gauge might not calibrate it's self correctly. I remember reading that when I installed it and THOUGHT that the power wire to the cigar lighter had power ALL the time. Guess not. that or the MAP sensor or gauge is crap but I would like to think thats not the case since the setup cost $150 vs $45 mechanical gauge.


Soooooo does anyone know of a full time power source thats easy to tap into?

 

[smokem]

The obvious source would be your battery. Just run a wire with a in line fuse, or you could tap in to your radio. Either should work.

 

[brassc2007]

a accersory prong in the fuse block or direct to the batter with an inline fuse possibly

 

[grnchevyz]

The easiest wire to be using is the IGNITION wire in the ignition harness.

1. Remove lower steering column cover.
2. Locate ignition harness.
3. Use the Black/White wire. (heavier gauge wire)
4. Put an in-line fuse (2.5a or 5a depending if you want more than the gauge on that power wire)

That should solve it unless you feel adventurous and create a constant 12v source during acc/ign/crank as I have with relays...I can send you diags of that if you wish.

Hope that helps.

 

[AWD-TSI]

fuse tap in the fuse panel inside should do the trick. U said constant power right? That is what i would do. make sure you dont tap into any airbag fuses that could turn out bad. just use a DVOM to make sure. U Shouldn't need more than a 1-2 amp fuse.

 

[grnchevyz]

For the Autometer gauges to initialize properly they require a constant 12v during crank, not all the time. To avoid residual drainage (however little it may be) ignition power and NOT accessory power should be used. Most people use an accessory wire and during crank, it goes to 0v and the gauge does not initialize properly. Having 12v constant will not let the gauge initialize every time, it will initialize the first time you put power to it and that's it. Having it initialize each time is a good idea to ensure proper calibration.

Hope that helps!

 

[lacroixdp]

IMHO, the safest way to do it is to use a device they sell at Autozone called Add-A-Fuse. Here's what they look like:
Amazon.com: Littelfuse FHA200BP ATO Add-A-Circuit Kit: Automotive
Basically, you put this in place of one of your other fuses, and your new circuit has a dedicated fuse. Just cut the blue end off, solder your wire on and heat shrink wrap it and you're set! I think they are 9 bucks or so at Autozone. They make a blade-type one that you rig in another fuse, but I had my first Talon catch on fire from the previous owner sticking one in improperly.

 

[RipperXX]

IMHO, the safest way to do it is to use a device they sell at Autozone called Add-A-Fuse. Here's what they look like:
Amazon.com: Littelfuse FHA200BP ATO Add-A-Circuit Kit: Automotive
Basically, you put this in place of one of your other fuses, and your new circuit has a dedicated fuse. Just cut the blue end off, solder your wire on and heat shrink wrap it and you're set! I think they are 9 bucks or so at Autozone. They make a blade-type one that you rig in another fuse, but I had my first Talon catch on fire from the previous owner sticking one in improperly.

This defiantly sounds like the easiest solution. But which fuse should I replace with it? I ask because I just doubt that any would work. I am trying to keep wiring stupid simple so it was that or I was going to go with wiring it straight to the with a 1amp fuse and call it good. But I don't like the idea of that because I don't really want it to have power with the keys not even in the ignition.

 

[RipperXX]

Ok, ran out and got the "add a circuit" thing 15min before the store closed now I just need to know which fuse to replace with it.

 

[grnchevyz]

You need a digital voltmeter or a testlight.

1. Ground it.
2. Touch the power side to one of the fuses. (voltmeter should be 0v or light off)
3. Turn ignition on. (should read 12v or so or light on)
4. Put key in start (crank) position and see voltage remain 12v or light stay on.
5. Change fuse if #4 goes to 0v on crank.

Hope that helps.

Edit: i still think putting an inline fuse at the ignition harness would have been simpler/cleaner

 

[RipperXX]

^ thanks, I was hoping someone knew of one off the top of there head... Oh well maybe I will get lucky and find one in the first few tries, though with my luck it will be the last one I test.

 

[lacroixdp]

I think fuse #18 meets the requirements of being on while cranking, if memory serves. According to the electrical schematics, it's the backup light. Definitely check it with a test light though (I could be wrong as hell ) - they are $2.99 at Harbor Freight if you don't have one.

 

[RipperXX]

^ it worked, thank you!





Gauge now works perfectly.