# Interesting thing with plug in air pump **URL:** \ **Category:** General Discussion\ **Created:** [April 25, 2023, 5:03am UTC](https://community.cartalk.com/t/interesting-thing-with-plug-in-air-pump/190259 "2023-04-25T05:03:48Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![Barkydog](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/barkydog/32/2470_2.png) [@Barkydog](https://community.cartalk.com/u/Barkydog)\ **Post date:** [April 25, 2023, 5:03am UTC](https://community.cartalk.com/t/interesting-thing-with-plug-in-air-pump/190259/1 "2023-04-25T05:03:48Z")
So last night I got home. Right rear tire low pressure. Wife was heading out today so I put the PSI up to spec with powerpoint compressor. Started the car to check low pressure for right rear alert gone, and left rear now low pressure. So I was filling it up. Said hon give me my keys while the tire gets air pressure. She turned off the car, and the pump slowed down. Figured it was the difference between battery voltage and charging voltage, She started the car with her key, and during start compressor slowed then popped up after the car was started. I remember old time way to check battery was to listen to the turn signal and how much difference in blinks from engine running and engine off. I could tell I needed a new battery when the blinks were too slow. Nothing of a serious note hear, hope it makes you think of something. ---
**Author:** ![bing](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bing/32/4619_2.png) [@bing](https://community.cartalk.com/u/bing)\ **Post date:** [April 25, 2023, 6:11am UTC](https://community.cartalk.com/t/interesting-thing-with-plug-in-air-pump/190259/2 "2023-04-25T06:11:32Z")
It made me think of a volt meter. I keep one in each car and plug it in once in a wile to check charging voltage and battery voltage at rest. Then every few months or when I think of it will do a cca check. The guys at the tire shop say though, the right rear has the most problems. Debris from the side of the road is picked up by the front tire then thrown back to the rear where it sticks. ---
**Author:** ![jtsanders](https://avatars.discourse-cdn.com/v4/letter/j/c2a13f/32.png) [@jtsanders](https://community.cartalk.com/u/jtsanders)\ **Post date:** [April 25, 2023, 1:28pm UTC](https://community.cartalk.com/t/interesting-thing-with-plug-in-air-pump/190259/3 "2023-04-25T13:28:57Z")
DC voltage is slightly higher during battery charging when the engine is running and that may be the reason the pump slowed down when it ran on the battery alone. It slowed down a lot during restart because the DC voltage was momentarily applied to the starting system. When the starter was disengaged the car was in charging mode with about 14 volts available, about 17% higher than the 12 volts at rest. I wouldn’t worry about it. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [April 26, 2023, 12:00am UTC](https://community.cartalk.com/t/interesting-thing-with-plug-in-air-pump/190259/4 "2023-04-26T00:00:12Z")
Everything you noticed seems what I’d expect to happen. I can usually tell when my car’s battery is overly discharged by the sound the starter motor makes during cranking. Measuring the battery voltage before engine is cold-started, then after it starts is the best quick-test imho. I’ve heard of the blinker method, but never tried it. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [April 26, 2023, 10:49pm UTC](https://community.cartalk.com/t/interesting-thing-with-plug-in-air-pump/190259/5 "2023-04-26T22:49:32Z")
It happens to be time for the Corolla to do its 20-30 minutes of idling, keep everything in top shape until that as of now uncertain time when it’s finally allowed back on the road. It’s been sitting unused for about a month, the most recent idling exercise. Before cranking engine, I measured the battery voltage. 11.8 volts. Ooops, much too low! I didn’t even attempt to crank engine. Instead I connected battery charger. Battery was discharged enough even battery charger balked at getting its thing on, at first. ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [April 27, 2023, 4:12am UTC](https://community.cartalk.com/t/interesting-thing-with-plug-in-air-pump/190259/6 "2023-04-27T04:12:06Z")
> [@George\_San\_Jose1](#): > > It happens to be time for the Corolla to do its 20-30 minutes of idling, keep everything in top shape until that as of now uncertain time when it’s finally allowed back on the road. Operating the engine with no place to go, do your neighbors enjoy this? Keep exercising those pistons. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [April 27, 2023, 10:27pm UTC](https://community.cartalk.com/t/interesting-thing-with-plug-in-air-pump/190259/7 "2023-04-27T22:27:18Z")
> [@Nevada\_545](#): > > do your neighbors enjoy this? When most of the neighbor’s start their cars, I notice that some smoke comes out the exhaust pipe. Are you suggesting I should complain to them about it? ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [April 27, 2023, 10:30pm UTC](https://community.cartalk.com/t/interesting-thing-with-plug-in-air-pump/190259/8 "2023-04-27T22:30:43Z")
Most people drive away after starting the engine, they don’t race the engine for 30 minutes in the driveway. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [April 27, 2023, 10:35pm UTC](https://community.cartalk.com/t/interesting-thing-with-plug-in-air-pump/190259/9 "2023-04-27T22:35:10Z")
Among the near-by neighbors, they have 20 cars to match each one of mine, and they start and drive almost all of them 2 - 5 times per day. 30 minutes of idling the Corolla once a month is your main worry? Really? Sort of like worrying about running the lawn mower for 15 minutes. ---
**Author:** ![VOLVO-V70](https://avatars.discourse-cdn.com/v4/letter/v/8e8cbc/32.png) [@VOLVO-V70](https://community.cartalk.com/u/VOLVO-V70)\ **Post date:** [April 27, 2023, 10:38pm UTC](https://community.cartalk.com/t/interesting-thing-with-plug-in-air-pump/190259/10 "2023-04-27T22:38:54Z")
George , what are you - a one person watch committee ? Either get this pre-historic Corolla back on the road or quit gripping. ---
**Author:** ![bing](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bing/32/4619_2.png) [@bing](https://community.cartalk.com/u/bing)\ **Post date:** [April 28, 2023, 1:45am UTC](https://community.cartalk.com/t/interesting-thing-with-plug-in-air-pump/190259/11 "2023-04-28T01:45:18Z")
George is in California where nothing is allowed. I’m sure if there was a tail pipe problem, five cars from the clean air board would be arriving post haste, maybe even with weapons drawn. As far as the lawn mower goes, I though you couldn’t use those? ---
**Author:** ![Barkydog](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/barkydog/32/2470_2.png) [@Barkydog](https://community.cartalk.com/u/Barkydog)\ **Post date:** [April 28, 2023, 6:43am UTC](https://community.cartalk.com/t/interesting-thing-with-plug-in-air-pump/190259/12 "2023-04-28T06:43:39Z")
Not complaining bought a new single stage snowblower a year ago september.Manual says change oil after 20 hours. Now I was lucky to get 10 hours, even after running the gas out. Changed the oil in fall anyway, probably not up to 20 hours yet. SE Wisconsin, waiting for the mega snow next year. Mississippi river is flooding due to record snowfall and melt, take your chances and pay your dues! ---
**Author:** ![bing](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bing/32/4619_2.png) [@bing](https://community.cartalk.com/u/bing)\ **Post date:** [April 28, 2023, 7:36am UTC](https://community.cartalk.com/t/interesting-thing-with-plug-in-air-pump/190259/13 "2023-04-28T07:36:50Z")
I gotta go but I average about ten hours a year on mine. Change oil, new plug, run the gas out, touch up, inspect, and wax for next year. I get about 40 hours on the mower though. Bought a pressure washer and was supposed to wait for five hours to change oil. Waited two years a just changed it anyway. Most unused piece of machinery I ever bought. Otoh when you need it comes in handy. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [April 28, 2023, 11:19pm UTC](https://community.cartalk.com/t/interesting-thing-with-plug-in-air-pump/190259/14 "2023-04-28T23:19:28Z")
> [@bing](#): > > As far as the lawn mower goes, I though you couldn’t use those? Gasoline lawn mowers are still allowed. New lawnmower purchases may have to be electric, don’t know. As far as idling a Corolla for 20 minutes once a month to keep it lubed, compared to typical daily vehicle usage commonplace here, benign, I doubt anybody notices or cares. I’d guess my v8/carb-equipped truck uses more gasoline just starting the engine.