I recently drove a newer U-Haul truck for a friend who moved, and was inspired by the A-pillar mounted vacuum gauge to help people drive more efficiently. I've been thinking about doing something like this to my 05 Super Duty with 5.4 engine. I have the A-pillar mount and the gauge. What I'm unsure of it exactly what I need to pick up at Advance Auto (or similar), and how to tie this into my truck's vacuum system.

Can any of you provide me a photo or two of what I need to do under the hood and a brief description.

Thank you very much,

Matt

 

I have been driving my new to me 2010 5.4 Super Duty like I have an egg under the gas pedal. No matter how easy I drive, I can't get 13mpg local driving. I have not taken my truck on a long highway trip yet to see if I can break the 13 barrier. A vacuum gauge could be nice but it won't help me.

 

I installed a vacuum gauge in mine a few years back when I did gauges.

It didn't really help to increase my mileage but it did point out that I was already driving it about as good as I could to get decent mileage.

I do think it might be useful as my motor gets more & more miles on it to diagnose problems though.

 

They are good in that a baseline can be recorded for that motor. On gassers you want to make sure not to use plenum vacuum. They were a feature in some cars for a brief time in the 70s to try and save fuel. Even nice quality gauges aren't too spendy, cheap ones read the same. Larger face is probably best for accuracy.

 

So how exactly does a vacuum gauge help with fuel economy?

 

You watch the gauge while you drive. The object is to achieve the highest vacuum while accelerating and cruising by altering your driving style, which will net you the best fuel mileage.

 

It's a visual indication of engine vacuum, when a lead foot is behind the wheel, the vacuum drops to Zero. It's not really "necessary" probably that's why they aren't standard equipment anymore too. They do work if used carefully. Smooth steady acceleratiion, avoid braking and sudden starts, anticipate stops, etc.

 

I always figured it was something to do with the PCM controlling the mix of fuel and air in closed loop so it tried to set a stoichiometric mixture based on airflow read at the MAF. Manifold vacuum is roughly a guestimate of airflow in the sense that the higher vacuum is a result of less air is flowing in, meaning the PCM would put in less fuel to mix with the lower volume of air. But it's only a guess because the PCM won't run lean to the point where something is damaged.

 

It can be more of a big deal when going from the old pre-gas rationing
days of the lead foot to the post-gas rationing. I think you will see more
effect when doing it was a carbureted engine then the EFI Engines.
But in both cases the less foot in it the higher the vacuum will be and
less fuel that will be going in do to less air.

The key all comes down to take off and slowing down. If you can avoid
a full stop then that will save some too. It takes more energy to get that
mass of truck moving again than if you can coast a bit.

If I see a light that is or is going to be red I take the food off the throttle
and coast a bit instead of running up at full speed and hitting the breaks
then having to restart from a dead stop. Yes it does **** off some people
that are in a hurry to get to the red light and wait. But I say up yours.
If they want me to push it they can pay for my diesel.

Sorry if I got into rant mode.

Sean

 

some how i don't think it would help me since as far as i know the gas pedal is a on off switch right? off or smashed into the floor

 

Second part of the original post...

 

Thanks Psyclopse! I was getting ready to try and bring it around to the original question again!

 

You need a T-fitting for a vacuum hose. You'd cut the hose on your engine, install the T fitting, then hook up the vacuum gauge to the T port.

 

Just buy a Scanguage II and plug it in to the OBD II port and it does the same thing.

 

Or the much easier to read (In my opinion) Ultra-Guage. UltraGauge OBDII Scan tool & Information Center
Only real downside is that the U-G doesn't read our trans temp like the Scanguage will.