The two new gauges (oil pressure, vacuum) in the performance package that's offered on the premium 2.3 and premium 5.0 2015 cars, what is the vacuum gauge suppose to tell you? I thought that was only for the 2.3 turbo, but it's also offered on the 5.0.

 

5L has the Vac gauge.
2.3L has a boost gauge.

Both have Oil Pressure gauge.


They show vacuum, boost and oil pressure

 

A Vacuum gauge tell you the vacuum(inHg) of the engine. Think the opposite of boost if you don't understand vaccum.

 

Depends on if your engine sucks or blows.

 

I think what he's asking (or at least what I'm asking) is what do I do with the information provided by a vacuum gauge. What does it mean when the engine is creating a lot of vacuum vs just a little or no vacuum? Is no vacuum even possible?

The boost gauge I get, but the vacuum gauge is a bit of a mystery.

 

It can tell you how the engine is running, assuming it's an actual vacuum gauge and reading realtime values, and not just some fancy idiot light like the coolant temp gauge.

There isn't any real need for it (especially in modern cars with all the sensors and electronics). I'm not sure why they put it in there, unless it's just to look cool. It can also be helpful in figuring fuel economy as it can show how much load the engine is under, but I don't really see how it would work any different the current MPG readouts in the dash.

ETA - the last time I was in a Uhaul truck it had a vacuum gauge with fuel economy readings on it. Basically showed roughly how economical you are driving at any given time. When you give it a lot of throttle the vacuum drops considerably, and less throttles increases the amount of vacuum. Instead of showing the amount of vacuum it just had a green/yellow/red zone for MPG (low vacuum = worse MPG).

 

The vacuum gauge is just a place holder, For the boost gauge when you add forced induction.

 

I hadn't thought about this much, till now...WTF-->Ford?? Adding a Ridiculous Gauge, no one will pay any attention to or understand (Maybe 1% will).

Guess when I have a friend with me and he/she asks, what's it for, I'll have to try & explain how useful & important it is-->

OR, if my friend is a 'Carguy', I'll ask "What do you think about these Gauges?" The expected answer will probably be something like, they are cool, or about time Gauges instead of Idiot Lights. Then I'll ask, "What does the Vacuum Gauge Do & Why do I need to Monitor it?"-->

 

 

Vacuum gauge is essentially the negative number extension if a positive number boost gauge and basically convey the same thing: the higher the pressure (or less the vacuum), the harder the motor's working, ergo: more fuel and air being burned, more power but less economy.

Many early "economy" gauges were little more than relabeled vacuum gauges.

 

if the gauges worked in real time that'd be pretty cool. No one knows if they'll work real time or not?

 

those questions will make his life hell.

 

A Vacuum gauge can tell you alot about your engine If you know how to read it Before cars were controlled by computers a vacuum gauge was a mechanics main tool for tuning in diagnosing engines.

 

Why make a different dash or wire in a different gauge. Keeps production costs down. If you ever add a blower, it's simple swap with no wiring change.

 

Vacuum gauges have been a valuable tool to mechanics for years. Even with modern computer controlled engines a vacuum gauge is still a valuable tool for diagnosing engine and transmission problems.*

Engine/Transmission Relations

An important part of transmission diagnosis is to make certain the engine operates properly. If the engine performance is incorrect, the transmission will receive the wrong information. Many times what is perceived as a transmission problem is in actuality an engine problem. The engine sends signals to the transmission through a vacuum line, throttle cable or both. These signals basically synchronize torque with transmission line pressure, shift feel and shift timing. Malfunctions in items like the air filter; spark plugs, EGR valves and other parts of the fuel, electrical and emission systems could result in improper transmission performance.

Vacuum Gauge Engine Performance Testing

A vacuum gauge shows the difference between outside atmospheric pressure and the amount of vacuum present in the intake manifold. The pistons in the engine serve as suction pumps and the amount of vacuum they create is affected by the related actions of:*
Piston ringsOther parts affecting the combustion process (emission devices, etc.).
Each has a characteristic effect on vacuum and you judge their performance by watching variations from normal. It is important to judge engine performance by the general location and action of the needle on a vacuum gauge, rather than just by a vacuum reading. Gauge readings that may be found are as follows:

Normal Engine Operation*
At idling speed, an engine at sea level should show a steady vacuum reading between 17" and 21" HG. A quick opening and closing of the throttle should cause vacuum to drop below 5" then rebound to 21" or more.

General Ignition Troubles Or Sticking Valves*
With the engine idling, continued fluctuation of 1 to 2 inches may indicate an ignition problem. Check the spark plugs, spark plug gap, primary ignition circuit, high tension cables, distributor cap or ignition coil. Fluctuations of 3 to 4 inches may be sticking valves.

Intake System Leakage, Valve Timing, Or Low Compression*
Vacuum readings at idle much lower than normal can indicate leakage through intake manifold gaskets, manifold-to-carburetor gaskets, vacuum brakes or the vacuum modulator. Low readings could also be very late valve timing or worn piston rings.

Exhaust Back Pressure*
Starting with the engine at idle, slowly increase engine speed to 3,000 RPM, engine vacuum should be equal to or higher than idle vacuum at 3,000 RPM. If vacuum decreases at higher engine RPM's, an excessive exhaust back pressure is probably present.

Cylinder Head Gasket Leakage*
With the engine Idling, the vacuum gauge pointer will drop sharply, every time the leak occurs. The drop will be from the steady reading shown by the pointer to a reading of 10" to 12" Hg or less. If the leak Is between two cylinders, the drop will be much greater. You can determine the location of the leak by compression tests.

 

Thank you for taking the time to spell it all out. BTW, can anyone tell me why you can't create a oil pressure gauge in the drivers customizing settings?

 

All '15 Mustangs have a vacuum "gauge" in the instrument cluster LCD screen.