Fuel Doctor dissected

[dkjones96]

The fuel doctor is an $80 device that claims to improve engine and transmission performance while increasing fuel economy. The site reads as such:

# The FD-47 was developed after years of research into engine dynamics that has yielded incredible results. It is an Electronic Current Regulator and De-magnetizing device that dramatically improves engine and transmission performance.
# Our product can be used in a car or truck that has 12-24 volt systems using gasoline, diesel, LPG or NGV. The FD-47 cannot be used in electric vehicles or hybrids with electrical assist.
# Our product will not damage your engine or electrical components. Test labs and field testing show a dramatic improvement in engine and transmission wear. The FD-47 will not damage your battery or the other electronic systems in the vehicle including audio systems, emissions performance, phone connections, etc.
# Our device will dramatically reduce the total emissions of the car through better gas mileage and reduced wear on the engine and its components. Our revolutionary product is an environment friendly device that significantly reduces your total emissions. Each year using our product, you will reduce the pollutants your vehicle emits into the air by over 1,000 pounds.

I decided today to take one apart and see just what is inside. I found two Zener diodes, 3 resistors, 2 capacitors 3 leds, and one unidentified empty sounding grey box labeled D4(as in diode).







According to the litereature it is supposed to even out dips in power usage. A good battery and alternator shouldn't need that and the two capacitors being 220uF and 47uF I don't see enough capacitance to make any real difference. MAYBE with a couple Farads of capacitance under the hood I could see it but not in this case. Especially through the 2 amp fuse it has.

[theclencher]

A useless fe device? Say it ain't so!!!

I WANNA BELIEVE!!!!

[BEEF]

did you burn $80 to test this?

[dkjones96]

Heeeeeeeeeck no. It was a gift but I wasn't at the show to see who was passing them out so I've got no real details about the person that gave it to us.

[bobc455]

I'm guessing the capacitors are just part of a circuit to make the lights blink (an RC circuit or something)

[Jay2TheRescue]

Heck, I could have made a flashing LED with a 555 timer...

[dkjones96]

Don't even need that anymore!

5mm Red Blinking LED

It has a low battery indicator on it which I assume is set off by one of the two Zener diodes. Once the voltage falls below its threshold it stops shorting the LED and it can light. At least, that's how I'd have done it.

And the normal one probably lights because they put that LED in series with its Zener so over 12 it shorts and the led lights and under 12 it stops.

[theholycow]

I think last year someone dissected a nearly identical device with a different name and it was pretty much the same. Does anyone remember that thread?

[Jay2TheRescue]

Yeah, the blinking LED... I haven't done many electronics projects in quite some time, so I'm not up on the "new" stuff available. Besides, using a 555 is like "Kickin' it old skool", "Cuz that's how I roll".

-Jay

[JoeBob]

In my former life as a manager at the 'shack, I sold a number of those blinking LEDs. IIRC, they came out late '80s or early '90s, right after I got bored one day and built a 555 LED blinker.

[Ford Man]

Did you test it before disecting it? I would have had to plug it into the cigarette lighter for a couple tanks just to satisfy my curiosity. Some of these fuel savers actually hurt gas mileage. The ones that hook up to the IAT sensor makes it send false signal to ECU telling it that the intake air is cooler than it actually is and we all know cold air makes a car run richer.

[Jay2TheRescue]

Yeah, I built one of those 555 LED flashers in the 7th grade (mid 80's)

[dkjones96]

It wasn't destroyed in the dismantling process. I left it at work but intended to run it anyways since it can't hurt anything... Or so I hope.

[markweatherill]

That grey box must be the plasma generator. Either that or the anti-gravity condenser.

[Jay2TheRescue]

It just might be a miniaturized flux capacitor.

[theholycow]

Originally Posted by Jay2TheRescue

It just might be a miniaturized flux capacitor.

[Greyg]

I'm thinking about installing a Heisenberg compensator on my mini-van.

[Jay2TheRescue]

That sounds cool.

[JanGeo]

It works on the principle that every time you look down to the right where the unit is plugged into the lighter plug you slightly lift your foot off the gas pedal thus saving fuel . . . other than the little black box being a source of energy from another parallel universe it does very little other than tell you when your battery is low by helping to run it down a little.

[Scott]

I undestand the theory, if you smooth out pulses in the electrical system, the shock will not go back to your fuel injectors and create a lean or rich condition that has to be compensated for. My Focus pules the lights a little at idle, every Ford I have even owned pules at idle, so it seems idle my be slightly effected, but that is at idle.

Now my Ford has high loads on it battery cables, if I dont keep them clean and greased with the head lights on and A/C on, there is not enough energy to keep the solenoids awake in the transmission and it will jump into first on the freeway, talk a bout a hay ride. As long as my terminals are clean, no problem.

Now where this device might help is in the electric clutch engaging the A/C magnetic clutch, there is probably the largest cycling pulse going through your electrical system. The pulse or surge is high and I dont think a little cigarette lighter capacitor will absorb and smooth that large amp pulse.

[BEEF]

I don't think that a 220uf cap is really going to make that big of a difference with pretty much anything. most large sound systems require a farad or more to really do much as far as current capacity and you usually have a 4 gauge (or bigger) wire going to it.

this is 220uf or better 0.00022 farads and it has a 2 amp fuse on it so it can only supply that much back through the system.

either way, It is a gimic to make someone money (and not the end user)

for your issue, I would either buy a bigger battery or alternator.

[theholycow]

Originally Posted by Scott

it will jump into first on the freeway,

[JoeBob]

What this thing reminds me of is the little auto electrical system tester R'oshack used to sell back in the '80s and '90s with a red, yellow and green LED to tell you how much voltage was reaching your cigarette lighter.

[Jay2TheRescue]

Its not surprising... The lighter socket is a very powerful power source...

Remember this?


http://www.thinkgeek.com/gadgets/car...ts&cpg=oggdgt1

[JoeBob]

Yes....Don't they still have those?

[Jay2TheRescue]

Yes they do. Click on the link under the picture if you'd like to buy one. Its only $24.99.

-Jay