Following a suggestion made on another forum, I have ordered an OTC vacuum gauge to check my V6 1MZFE engine. Have been doing research to learn what various reading indicate. You don’t hear much about vacuum gauges these days. I was wondering if ECM’s and OBD code readers have made them obsolete? As some of you know from my other posts, I am chasing a cabin vibration. My car is idling and running fine with excellent fuel trims and no codes. I willlet you know what the vacuum gauge tells me.
Are Vacuum Gauges Obsolete?
- Thread starter artbuc
- Start date
- Status
I think they still have a place in a tool box, even though there seem to be less vacuum lines in use now. I think the problem today with "some" techs is if the scanner doesn't point to a code they're lost and don't know how to use tools like a vacuum gauge, to actually troubleshoot an engine.
As long as pistons keep going up and down the vacuum gauge will remain one of the most valuable tools in the box if you know how to use it.
Engines today pull the same amount of vacuum as they did a 100 years ago, its true there are not as many vacuum operated systems as there were at one time, distributor advance, choke pull offs, heat risers, etc but that's not the point of using the gauge which is to measure manifold and in some cases ported vacuum. Testing vacuum operated components can be done with a hand held vacuum pump.
With the gauge connected in just a couple of minutes you can tell if the engine has a bad cat, worn rings, valves, guides, and all sorts of other things. You made a wise purchase, practice using it and get a feel for what an engine in good condition looks like.
https://www.motor.com/magazine-summary/mastering-the-basics-reading-a-vacuum-gauge/
http://www.onallcylinders.com/2015/05/08...ngine-problems/
Engines today pull the same amount of vacuum as they did a 100 years ago, its true there are not as many vacuum operated systems as there were at one time, distributor advance, choke pull offs, heat risers, etc but that's not the point of using the gauge which is to measure manifold and in some cases ported vacuum. Testing vacuum operated components can be done with a hand held vacuum pump.
With the gauge connected in just a couple of minutes you can tell if the engine has a bad cat, worn rings, valves, guides, and all sorts of other things. You made a wise purchase, practice using it and get a feel for what an engine in good condition looks like.
https://www.motor.com/magazine-summary/mastering-the-basics-reading-a-vacuum-gauge/
http://www.onallcylinders.com/2015/05/08...ngine-problems/
Just wondering. Where would be a good place to hook up to physically check the intake manifold vacuum.
Any port behind the throttle plate. You can T in if you have too, just remove a hose put another hose on the end of the T and the gauge in the middle. Before the throttle plate will be ported vacuum which is very low at idle but increases with RPM.
Vacuum gauges are not obsolete. They will tell you many things about engine operation like Trav stated. I learned how to use one when I started working on cars well over 50 years ago. My vacuum gauge is still one of the valuable tools in my tool box. I own a 1963 Studebaker Avanti that has one built into the instrument panel and my 1962 Studebaker Hawk has one added to the panel. If you watch the gauge when driving and keep the vacuum above 10 inches, the fuel economy can improve by two or three MPG.
I used a vacuum gauge to tune the distributor after my timing light died. My old BMWs had an "econo-meter" that behaved similarly, but was totally electrical
A modern engine is still nothing more than an air pump. A computer controlled pump but the basics still apply. On board computers and diagnostics are just another tool in the tool box. A vacuum gauge and compression tester are still essential tools for me.
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).
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).
They still all apply to my "present" as I don't (won't) own any of the new fangled stuff
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
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
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, like my 1er.
Pretty much all BMW and Mini are like this now.
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, like my 1er.
Pretty much all BMW and Mini are like this now.
Last edited:
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, like my 1er.
Pretty much all BMW and Mini are like this now.
Don't have accessible vacuum but they create a vacuum nonetheless. Like diesels, blowers, some tunnel rams, big cams vacuum may be too low to get meaningful reading, vacuum pumps are common on these engines.
Its not like new engines are causing the tool to become less useful, there were always some. Most will continue to have intakes and plenums.
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, like my 1er.
Pretty much all BMW and Mini are like this now.
Don't have accessible vacuum but they create a vacuum nonetheless. Like diesels, blowers, some tunnel rams, big cams vacuum may be too low to get meaningful reading, vacuum pumps are common on these engines.
Its not like new engines are causing the tool to become less useful, there were always some. Most will continue to have intakes and plenums.
JHZR2
Staff member
My BMW doesn't have vacuum the same way - it's all valve operation. Forget exactly how, but the throttle plate is rarely/barely in use.
So a vacgauge on my car isn't of much use other than as a boost gauge
So a vacgauge on my car isn't of much use other than as a boost gauge
Originally Posted By: NHGUY
Chrysler's "Fuel pacer" was a vacuum gauge without a gauge.It lit the left fender mounted turn signal indicator when you stomp down too much.GM in the 70s had the "econominder" gauge.
Mercedes and BMW also had that up until the 1990s, the MPG gauge is still in the latter but probably working off an algorithm. It was a direct vacuum line to the intake plenum.
There's still vacuum in new cars - even in throttleless BMWs and Toyota's Valvematic system. It's supplied externally in some cases to work the brake booster but also EVAP also needs vacuum to operate(routing vapors into the engine while purging the canister).
Chrysler's "Fuel pacer" was a vacuum gauge without a gauge.It lit the left fender mounted turn signal indicator when you stomp down too much.GM in the 70s had the "econominder" gauge.
Mercedes and BMW also had that up until the 1990s, the MPG gauge is still in the latter but probably working off an algorithm. It was a direct vacuum line to the intake plenum.
There's still vacuum in new cars - even in throttleless BMWs and Toyota's Valvematic system. It's supplied externally in some cases to work the brake booster but also EVAP also needs vacuum to operate(routing vapors into the engine while purging the canister).
It's not just BMW valvetronic that bucks the trend, MOST cars now are using aggressive miller timing as well (also called atkinson cycle, but atkinson is specific to 'expansion ratio' and his original design was an epicyclic piston stroke, so I don't like using 'atkinson' for miller valve timing events like some others in the industry)
Not to say that a vacuum gauge would be useless on the newer valve timing regimes intended to slash pumping losses, but you wont be able to interpret the data the same way as in the past. All you'd really be able to see is when the miller valve timing is active, to what degree and when the vacuum pump is being used. Not useless info, just totally different context.
Not to say that a vacuum gauge would be useless on the newer valve timing regimes intended to slash pumping losses, but you wont be able to interpret the data the same way as in the past. All you'd really be able to see is when the miller valve timing is active, to what degree and when the vacuum pump is being used. Not useless info, just totally different context.
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, like my 1er.
Pretty much all BMW and Mini are like this now.
How is the intake regulated?
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, like my 1er.
Pretty much all BMW and Mini are like this now.
How is the intake regulated?
Originally Posted By: Trav
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, like my 1er.
Pretty much all BMW and Mini are like this now.
Don't have accessible vacuum but they create a vacuum nonetheless. Like diesels, blowers, some tunnel rams, big cams vacuum may be too low to get meaningful reading, vacuum pumps are common on these engines.
Its not like new engines are causing the tool to become less useful, there were always some. Most will continue to have intakes and plenums.
Refer this all back to the thread about how do tell if cam lobes are gone. Vacuum gage can tell you a whole bunch if you can just read it.
Smoky
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, like my 1er.
Pretty much all BMW and Mini are like this now.
Don't have accessible vacuum but they create a vacuum nonetheless. Like diesels, blowers, some tunnel rams, big cams vacuum may be too low to get meaningful reading, vacuum pumps are common on these engines.
Its not like new engines are causing the tool to become less useful, there were always some. Most will continue to have intakes and plenums.
Refer this all back to the thread about how do tell if cam lobes are gone. Vacuum gage can tell you a whole bunch if you can just read it.
Smoky
- Status
Similar threads
