Why are you telling me this?
Are Vacuum Gauges Obsolete?
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Originally Posted By: mightymousetech
Originally Posted By: Trav
Engines today pull the same amount of vacuum as they did a 100 years ago,
Except on a large number of cars these days that don't have vacuum due to no throttle body, ...
Then there are engines which do have throttle bodies, but work through CVT or e-CVT transmissions and electronic control systems to maintain relatively constant near-ideal vacuum level even with varying power demand.
I used a vacuum gauge on my Mazda, but haven't bothered installing it on the Prius, because manifold vacuum is nearly constant, except at very light loads or when it's idling to warm up. Besides, I can see MAP (essentially the same information) on my Scan Gauge.
Originally Posted By: Trav
Engines today pull the same amount of vacuum as they did a 100 years ago,
Except on a large number of cars these days that don't have vacuum due to no throttle body, ...
Then there are engines which do have throttle bodies, but work through CVT or e-CVT transmissions and electronic control systems to maintain relatively constant near-ideal vacuum level even with varying power demand.
I used a vacuum gauge on my Mazda, but haven't bothered installing it on the Prius, because manifold vacuum is nearly constant, except at very light loads or when it's idling to warm up. Besides, I can see MAP (essentially the same information) on my Scan Gauge.
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Still an important tool for me - if I have a running issue and no codes, then plug in the vacuum guage for an idea of how the engine is running.
The CVT is not controlling engine vacuum when the car is not moving. You can check the MAP sensor with a vacuum gauge.
http://autoditex.com/page/manifold-absolute-pressure-sensor-map-sensor-20-1.html
http://autoditex.com/page/manifold-absolute-pressure-sensor-map-sensor-20-1.html
You can use your vacuum tool to verify that the vacuum brake booster still functions properly. I saw someone waste a lot of money on a Ford 6.0 PSD because they assumed that a stiff brake pedal was caused by a failed brake booster. After replacing the booster, they then discovered that the belt driven vacuum pump had failed.
I guess not needed for modern cars.
But I use mine for my '68 L36 Corvette Roadster (mostly original), '65 4-4-2 (very original), my friends' older work trucks, etc.
They tell you what your engine likes.
But I use mine for my '68 L36 Corvette Roadster (mostly original), '65 4-4-2 (very original), my friends' older work trucks, etc.
They tell you what your engine likes.
Originally Posted By: Trav
Why are you telling me this?
Not telling you, it was for anyone else who might be thinking of the post on flat cam lobes. I kinda figured you were on top of the vac gage to spot flat cam lobes.
Smoky
Why are you telling me this?
Not telling you, it was for anyone else who might be thinking of the post on flat cam lobes. I kinda figured you were on top of the vac gage to spot flat cam lobes.
Smoky
Originally Posted By: Trav
Originally Posted By: ctrcbob
Things of the past..
1. Timing Light.
2. Dwell Meter..
3. Points.
4. Condenser (really a capacitor).
5. Distributor.
6. Ignition Coil.
7. Spark Plug Wires.
8. Feeler gauge. (Some people still use to gap spark plugs).
9. Carburetors. (Named for French word for fuel -Carburants).
Probably many others that I can't think of at the moment.
(I was going to mention "Wet Clutch" [vice the more common Dry Clutch] but there are still some vehicles, (motorcycles) that use a Wet Clutch). (My next door neighbor restored a 1950 or 1951 Hudson That used a Wet Clutch).
Feeler gauges are still used for valve clearance, ring end gap, surface flatness, etc so definitely not obsolete.
A strobe in the form of a common timing light can be used to check for sticking valves, also not obsolete not just as commonly needed.
Ignition coil, every gasoline engine has one or more unless its a magneto.
Every automatic transmission and many AWD transfer cases use wet clutches.
You can replace many parts of a gasoline engine with other parts of newer technology but its still a 130 year old + design.
Basically there is no such thing as a modern gasoline engine if you think about it. Its like a modern incandescent bulb. LOL
Some people still use feeler gauges to gap plugs too. I would never put a plug in without checking the gap. And almost all systems still use an ignition condenser.
On my Gen Coupe with a Boost gauge it reads the vacuum too in -psi. The Torque app will convert this to "Hg.
Originally Posted By: ctrcbob
Things of the past..
1. Timing Light.
2. Dwell Meter..
3. Points.
4. Condenser (really a capacitor).
5. Distributor.
6. Ignition Coil.
7. Spark Plug Wires.
8. Feeler gauge. (Some people still use to gap spark plugs).
9. Carburetors. (Named for French word for fuel -Carburants).
Probably many others that I can't think of at the moment.
(I was going to mention "Wet Clutch" [vice the more common Dry Clutch] but there are still some vehicles, (motorcycles) that use a Wet Clutch). (My next door neighbor restored a 1950 or 1951 Hudson That used a Wet Clutch).
Feeler gauges are still used for valve clearance, ring end gap, surface flatness, etc so definitely not obsolete.
A strobe in the form of a common timing light can be used to check for sticking valves, also not obsolete not just as commonly needed.
Ignition coil, every gasoline engine has one or more unless its a magneto.
Every automatic transmission and many AWD transfer cases use wet clutches.
You can replace many parts of a gasoline engine with other parts of newer technology but its still a 130 year old + design.
Basically there is no such thing as a modern gasoline engine if you think about it. Its like a modern incandescent bulb. LOL
Some people still use feeler gauges to gap plugs too. I would never put a plug in without checking the gap. And almost all systems still use an ignition condenser.
On my Gen Coupe with a Boost gauge it reads the vacuum too in -psi. The Torque app will convert this to "Hg.
Originally Posted By: Smoky14
Originally Posted By: Trav
Why are you telling me this?
Not telling you, it was for anyone else who might be thinking of the post on flat cam lobes. I kinda figured you were on top of the vac gage to spot flat cam lobes.
Smoky
Misunderstood, I don't remember posting in that thread that's why I was wondering. Your right, it can be useful in diagnosing a bad lobe.
Originally Posted By: Trav
Why are you telling me this?
Not telling you, it was for anyone else who might be thinking of the post on flat cam lobes. I kinda figured you were on top of the vac gage to spot flat cam lobes.
Smoky
Misunderstood, I don't remember posting in that thread that's why I was wondering. Your right, it can be useful in diagnosing a bad lobe.
Originally Posted By: SHOZ
Originally Posted By: Trav
Originally Posted By: ctrcbob
Things of the past..
1. Timing Light.
2. Dwell Meter..
3. Points.
4. Condenser (really a capacitor).
5. Distributor.
6. Ignition Coil.
7. Spark Plug Wires.
8. Feeler gauge. (Some people still use to gap spark plugs).
9. Carburetors. (Named for French word for fuel -Carburants).
Probably many others that I can't think of at the moment.
(I was going to mention "Wet Clutch" [vice the more common Dry Clutch] but there are still some vehicles, (motorcycles) that use a Wet Clutch). (My next door neighbor restored a 1950 or 1951 Hudson That used a Wet Clutch).
Feeler gauges are still used for valve clearance, ring end gap, surface flatness, etc so definitely not obsolete.
A strobe in the form of a common timing light can be used to check for sticking valves, also not obsolete not just as commonly needed.
Ignition coil, every gasoline engine has one or more unless its a magneto.
Every automatic transmission and many AWD transfer cases use wet clutches.
You can replace many parts of a gasoline engine with other parts of newer technology but its still a 130 year old + design.
Basically there is no such thing as a modern gasoline engine if you think about it. Its like a modern incandescent bulb. LOL
Some people still use feeler gauges to gap plugs too. I would never put a plug in without checking the gap. And almost all systems still use an ignition condenser.
On my Gen Coupe with a Boost gauge it reads the vacuum too in -psi. The Torque app will convert this to "Hg.
I use a wire gauge on plugs and usually nothing on precious metal electrodes unless its obviously been bashed. Plug manufacturers are specifically telling installers not to gap.
I guess they had too many pucks knocked loose. To be honest I never had any problem either way.
Originally Posted By: Trav
Originally Posted By: ctrcbob
Things of the past..
1. Timing Light.
2. Dwell Meter..
3. Points.
4. Condenser (really a capacitor).
5. Distributor.
6. Ignition Coil.
7. Spark Plug Wires.
8. Feeler gauge. (Some people still use to gap spark plugs).
9. Carburetors. (Named for French word for fuel -Carburants).
Probably many others that I can't think of at the moment.
(I was going to mention "Wet Clutch" [vice the more common Dry Clutch] but there are still some vehicles, (motorcycles) that use a Wet Clutch). (My next door neighbor restored a 1950 or 1951 Hudson That used a Wet Clutch).
Feeler gauges are still used for valve clearance, ring end gap, surface flatness, etc so definitely not obsolete.
A strobe in the form of a common timing light can be used to check for sticking valves, also not obsolete not just as commonly needed.
Ignition coil, every gasoline engine has one or more unless its a magneto.
Every automatic transmission and many AWD transfer cases use wet clutches.
You can replace many parts of a gasoline engine with other parts of newer technology but its still a 130 year old + design.
Basically there is no such thing as a modern gasoline engine if you think about it. Its like a modern incandescent bulb. LOL
Some people still use feeler gauges to gap plugs too. I would never put a plug in without checking the gap. And almost all systems still use an ignition condenser.
On my Gen Coupe with a Boost gauge it reads the vacuum too in -psi. The Torque app will convert this to "Hg.
I use a wire gauge on plugs and usually nothing on precious metal electrodes unless its obviously been bashed. Plug manufacturers are specifically telling installers not to gap.
I guess they had too many pucks knocked loose. To be honest I never had any problem either way.
Originally Posted By: Trav
Originally Posted By: SHOZ
Originally Posted By: Trav
Originally Posted By: ctrcbob
Things of the past..
1. Timing Light.
2. Dwell Meter..
3. Points.
4. Condenser (really a capacitor).
5. Distributor.
6. Ignition Coil.
7. Spark Plug Wires.
8. Feeler gauge. (Some people still use to gap spark plugs).
9. Carburetors. (Named for French word for fuel -Carburants).
Probably many others that I can't think of at the moment.
(I was going to mention "Wet Clutch" [vice the more common Dry Clutch] but there are still some vehicles, (motorcycles) that use a Wet Clutch). (My next door neighbor restored a 1950 or 1951 Hudson That used a Wet Clutch).
Feeler gauges are still used for valve clearance, ring end gap, surface flatness, etc so definitely not obsolete.
A strobe in the form of a common timing light can be used to check for sticking valves, also not obsolete not just as commonly needed.
Ignition coil, every gasoline engine has one or more unless its a magneto.
Every automatic transmission and many AWD transfer cases use wet clutches.
You can replace many parts of a gasoline engine with other parts of newer technology but its still a 130 year old + design.
Basically there is no such thing as a modern gasoline engine if you think about it. Its like a modern incandescent bulb. LOL
Some people still use feeler gauges to gap plugs too. I would never put a plug in without checking the gap. And almost all systems still use an ignition condenser.
On my Gen Coupe with a Boost gauge it reads the vacuum too in -psi. The Torque app will convert this to "Hg.
I use a wire gauge on plugs and usually nothing on precious metal electrodes unless its obviously been bashed. Plug manufacturers are specifically telling installers not to gap.
I guess they had too many pucks knocked loose. To be honest I never had any problem either way.
Actually they say not to use a wire gauge on the puck style plugs. And gapping is easily done by bending the electrode with a needle nose. My Gen Coupe plugs use to come gapped to .043" which is the factory manual spec. But it will misfire under load so they dropped that down to .030" and the new plugs come gapped close to this.
Originally Posted By: SHOZ
Originally Posted By: Trav
Originally Posted By: ctrcbob
Things of the past..
1. Timing Light.
2. Dwell Meter..
3. Points.
4. Condenser (really a capacitor).
5. Distributor.
6. Ignition Coil.
7. Spark Plug Wires.
8. Feeler gauge. (Some people still use to gap spark plugs).
9. Carburetors. (Named for French word for fuel -Carburants).
Probably many others that I can't think of at the moment.
(I was going to mention "Wet Clutch" [vice the more common Dry Clutch] but there are still some vehicles, (motorcycles) that use a Wet Clutch). (My next door neighbor restored a 1950 or 1951 Hudson That used a Wet Clutch).
Feeler gauges are still used for valve clearance, ring end gap, surface flatness, etc so definitely not obsolete.
A strobe in the form of a common timing light can be used to check for sticking valves, also not obsolete not just as commonly needed.
Ignition coil, every gasoline engine has one or more unless its a magneto.
Every automatic transmission and many AWD transfer cases use wet clutches.
You can replace many parts of a gasoline engine with other parts of newer technology but its still a 130 year old + design.
Basically there is no such thing as a modern gasoline engine if you think about it. Its like a modern incandescent bulb. LOL
Some people still use feeler gauges to gap plugs too. I would never put a plug in without checking the gap. And almost all systems still use an ignition condenser.
On my Gen Coupe with a Boost gauge it reads the vacuum too in -psi. The Torque app will convert this to "Hg.
I use a wire gauge on plugs and usually nothing on precious metal electrodes unless its obviously been bashed. Plug manufacturers are specifically telling installers not to gap.
I guess they had too many pucks knocked loose. To be honest I never had any problem either way.
Actually they say not to use a wire gauge on the puck style plugs. And gapping is easily done by bending the electrode with a needle nose. My Gen Coupe plugs use to come gapped to .043" which is the factory manual spec. But it will misfire under load so they dropped that down to .030" and the new plugs come gapped close to this.
When I go to look at an MG for possible purchase(whether for me, or if I'm looking at one for someone else), I always bring my Mighty Vac and-provided that the owner is okay with me doing it. It's a great diagnostic tool to get a snapshot of engine condition. I'm hardly an expert at reading them, but I do have a general idea of what it should like at idle and can spot major problems pretty easily. I bring my compression gauge along also, although it doesn't tell as much as the vacuum gauge.
Granted that's an old car with an even older engine design, but the principle is there. If it's a 75 or later, I just pull the line going to the brake booster and plug the Mightvac in there. If it's a pre-75, I have to screw a fitting into the intake manifold(I carry the correct fitting with me), something which the owner may or may not be okay with.
I fitted a vacuum gauge in my own car, although it's damped somewhat to smooth out the fluctuations that you will see on a true diagnostic gauge. Of course, I fitted an old Smith's gauge to match the rest of the instruments in the car. The one marked in numbers is actually a bit difficult to find-the much more common one uses the exact same internal mechanics but has the scale calibrated in terms of fuel economy.
For quick and dirty on a modern car, it's easy enough to read the MAP sensor with a cheap USB OBD-II plug and laptop. With the right software, you can even have it generate a graph while you're driving that you can look at later. BTW, everything I deal with is still old enough to us engine vacuum for the brake servo-that remains a great place to connect your diagnostic vacuum gauge provided that you're working in the driveway/garage/shop and not actually driving the car.
Granted that's an old car with an even older engine design, but the principle is there. If it's a 75 or later, I just pull the line going to the brake booster and plug the Mightvac in there. If it's a pre-75, I have to screw a fitting into the intake manifold(I carry the correct fitting with me), something which the owner may or may not be okay with.
I fitted a vacuum gauge in my own car, although it's damped somewhat to smooth out the fluctuations that you will see on a true diagnostic gauge. Of course, I fitted an old Smith's gauge to match the rest of the instruments in the car. The one marked in numbers is actually a bit difficult to find-the much more common one uses the exact same internal mechanics but has the scale calibrated in terms of fuel economy.
For quick and dirty on a modern car, it's easy enough to read the MAP sensor with a cheap USB OBD-II plug and laptop. With the right software, you can even have it generate a graph while you're driving that you can look at later. BTW, everything I deal with is still old enough to us engine vacuum for the brake servo-that remains a great place to connect your diagnostic vacuum gauge provided that you're working in the driveway/garage/shop and not actually driving the car.
many years ago i started using a vacuum gauge to keep my MPG under control. i ran it a few different mopar engines , the mild stock kind. i tryed to not let the vacuum get below 10. now i have an 08 Avalon. it has only a tach. and if i keep it under 2,000 RPM in reg driving. it gets very good MPG.
With OBDII, watching the Load value is the king of the sensors. It basically takes rpm and air flow and comes up with % load. This will tell you in another way what the vacuum is telling you.
Most Naturally Aspirated engines get around 90% at peak torque. Forced Induction motors, it all depends on what's cramming the air in. With my stock turbo and a tune on my Gen Coupe see over 200% easily. It depends on the air temp.
You have to monitor Absolute Load to get to see over 100%, just Load is limited to 100%
Most Naturally Aspirated engines get around 90% at peak torque. Forced Induction motors, it all depends on what's cramming the air in. With my stock turbo and a tune on my Gen Coupe see over 200% easily. It depends on the air temp.
You have to monitor Absolute Load to get to see over 100%, just Load is limited to 100%
Originally Posted By: Trav
The CVT is not controlling engine vacuum when the car is not moving. You can check the MAP sensor with a vacuum gauge. ...
Assuming you're referring to my previous post ...
True, but unless the engine is cold, when the car is not moving the engine is normally* stopped, so vacuum is zero. If the MAP sensor malfunctions, I'd probably be warmed by obvious symptoms and a code.
*It's possible to make the engine idle when it's warm and the wheels are stopped, by doing a special chicken dance to enter a diagnostic mode. So far, I've used that trick only once, to re-warm the engine for an oil change.
The CVT is not controlling engine vacuum when the car is not moving. You can check the MAP sensor with a vacuum gauge. ...
Assuming you're referring to my previous post ...
True, but unless the engine is cold, when the car is not moving the engine is normally* stopped, so vacuum is zero. If the MAP sensor malfunctions, I'd probably be warmed by obvious symptoms and a code.
*It's possible to make the engine idle when it's warm and the wheels are stopped, by doing a special chicken dance to enter a diagnostic mode. So far, I've used that trick only once, to re-warm the engine for an oil change.
Originally Posted By: CR94
Assuming you're referring to my previous post ...
True, but unless the engine is cold, when the car is not moving the engine is normally* stopped, so vacuum is zero. If the MAP sensor malfunctions, I'd probably be warmed by obvious symptoms and a code.
*It's possible to make the engine idle when it's warm and the wheels are stopped, by doing a special chicken dance to enter a diagnostic mode. So far, I've used that trick only once, to re-warm the engine for an oil change.
So whats the problem hook a vacuum gauge up? The scan tool will not tell you everything. That has nothing to do with CVT it has to do with start/stop.
Assuming you're referring to my previous post ...
True, but unless the engine is cold, when the car is not moving the engine is normally* stopped, so vacuum is zero. If the MAP sensor malfunctions, I'd probably be warmed by obvious symptoms and a code.
*It's possible to make the engine idle when it's warm and the wheels are stopped, by doing a special chicken dance to enter a diagnostic mode. So far, I've used that trick only once, to re-warm the engine for an oil change.
So whats the problem hook a vacuum gauge up? The scan tool will not tell you everything. That has nothing to do with CVT it has to do with start/stop.
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