Why isn’t my car reading it’s rpm?
It just started not reading it's rpm. Everything else seems fine. But I do need an oil change and probably an all around tune up. I'm a single mom though with very little savings.
My car has 190000 miles.
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
Hi There,
This could be related to a couple of possibilities. The [instrument voltage regulator]((https://www.yourmechanic.com/services/instrument-voltage-regulator-replacement) regulates the voltage supplied to the various gauges in your vehicle’s dash. When this is not working properly, this may cause the gauges in your dash to dim or flicker erratically or in some cases provide false readings.
This may also be caused by a faulty transmission speed sensor. The speed sensor reads the rotational speed of the reluctor wheel, located within the transmission. The speed sensor also controls the anti-lock braking system. Driving with a bad speed sensor usually causes the ABS to malfunction and can lead to loss of braking power and/or an accident. When this is not working properly, you may also notice the transmission hesitating to shift gears, erratic tachometer readings, the speedometer not working properly or the odometer not working properly. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.
How to Identify and Fix Common car Problems ?
Our sources include academic articles, blog posts, and personal essays from experienced mechanics :
You can check to see if you have faulty wiring by using a voltmeter. Keep your engine idling and then test the wires with the voltmeter to see if there are any inconsistencies. Your mechanic can easily perform this test for you. If the wires are fine, then the gauge itself might be damaged and may need to be replaced.
If your RPM starts fluctuating, there might be issues with the engine`s combustion process, a communication gap between the IAC and the ECU, or it can be a worn-out spark plug.
If the RPMs are too high, try dropping it down a gear. This can solve the problem quickly and easily. Depending on what equipment the engine is hooked up to, you may be able to control the RPMs with gears. If the RPMs are too high, try dropping it down a gear.
If your engine revs up as you press down on the gas but your vehicle doesn`t accelerate as much as you`d expect, you may be dealing with transmission slipping. If you`ve ever tried to accelerate on ice, where your engine revs but your vehicle goes nowhere, you know the feeling.
The shaft RPM sensor is typically mounted to the tail shaft of the machine being monitored. The sensor is mounted in the EZ 1 Mag mounting bracket assembly, which attaches to the tail shaft with a 1/2″-13 UNC tapped hole.
In most cases it`s due to clogged exhaust or fuel pump, that requires a quick clean by a professional. Or usually a bad spark plug that is stopping your engine working to full power. Either way you should get the car checked out by a professional to fix the loss of power.
The answer is the crankshaft, which is spun by the motion of the pistons moving up and down in the cylinders as the spark plugs fire and detonate the fuel that`s fed to the engine. The pistons are connected to the crankshaft by rods.
In order to operate at a suitable RPM, a transmission makes use of gears; the gears vary how much torque and angular velocity is transmitted from the engine to the wheel, therefore allowing the RPM to remain below redline while also providing maximum horsepower.
Why does my car not accelerate when I push the gas? A car not accelerating properly can be caused by a number of things. It could be due to the throttle body, gas tank, spark plugs, or the ECU. It could also be because you have a dirty air filter or a clogged fuel filter.
Start the engine and read the screen on the tachometer.
While holding the tachometer, ask a friend to get into the vehicle and turn the key in the ignition. Once the engine starts, the tachometer will begin displaying the number of RPMs the engine is running at.
Most cars should idle between 600 RPM and 1,000 RPM. Cars that idle below 600 RPM or above 1,000 RPM may have a mechanical issue that you need to address. Additionally, if the RPM jumps around when idling, this also may be a sign of a bigger problem.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
Sounds as if the car is not going into gear. I have RPM reading odometer, not sure what it should be reading when driving on freeway.
ANSWER : Hello and thank you for contacting YourMechanic. Watch the tachometer (rpm gauge) as the vehicle is in motion. When driving, you should see the tachometer go up and then go down a little when the transmission shifts gears. For 4 cylinder engines with a 4 speed transmission, the RPM’s will be at 3,000 when driving at 70 mph on the highway. This is a normal condition for your vehicle and you should be okay. If you are very concerned about the noise or begin experiencing drivability problems, have a professional, like one from YourMechanic, diagnose the car sound and determine if any adjustments are needed.
After driving awhile, when idling, RPM drops below 500 & car stalls. Happens rarely but RPM fluctuates, and drops suddenly.
ANSWER : If you are having a stalling problem then you may have a computer code stored in memory. I suggest having the computer scanned to see if there is any codes stored and diagnose them as needed. The intake hose and air filter should be inspected for leaks in the hoses and dirty or leaking air filters. If the air filter is dirty or leaking then have the mass air sensor cleaned. If you still need help, have a mechanic diagnose the stalling issue for you and let you know exactly what repairs should be done.
I put the wrong key in my car and a few weeks later my car just shut down and it will not start I believe it’s the computer but…
ANSWER : Hi there. What had happened is the wrong key set the security to the vehicle. This is to prevent the vehicle from starting with the wrong keys. Try removing the battery cables (+) and (-) for 13 minutes. During that time, put the original key in the ignition and turn it on. Activate everything in the car even though there is no power. Then remove the key and hook up the battery cables. The computer should have reset and reset the security. If the security is still being tripped, then I recommend seeking out a professional, such as one from Your Mechanic, to help you
Replaced alternator on car 2 times each time shows it’s charging 14v let car run for a little bit then test drive and car voltage
ANSWER : There are reports that the replacement alternators will not communicate with the engine computer and will not charge correctly. I recommend using only the manufacturer approved replacement part. It can be new or remanufactured but approved for use in the vehicle. Some lower cost alternators on the aftermarket will have charging problems since they will not communicate with the ECM on the vehicle and will stop charging.
Should I buy this car for $1700
ANSWER : Prior to buying any car, drive the car around and listen for any noises. Then do an inspection on the vehicle to make sure that it is safe to drive. All cars will need maintenance, but if the car was kept up, then the maintenance should be to a minimum.
Rear battery isn’t charging.
ANSWER : If you had the key on for an extended period of time without the engine running, you may have run the accessory battery down. It really should last longer than a car wash though, so maybe it needs replacing. Your car has high-output alternator and a power management module that decides where to draw the power and where to send the charging voltage according to need. So if everything in the system is working, the battery really should be able to hold up for a few hours. When the battery voltage gets really low, things just start to go haywire and the car may start to act as though it was haunted. By contacting Your Mechanic, you can have a technician come to your home or office to check out your Mercedes and let you know it you need a battery replacement or other charging system service.
Why isn’t my car reading it’s rpm?
ANSWER : Hi There,
This could be related to a couple of possibilities. The [instrument voltage regulator]((https://www.yourmechanic.com/services/instrument-voltage-regulator-replacement) regulates the voltage supplied to the various gauges in your vehicle’s dash. When this is not working properly, this may cause the gauges in your dash to dim or flicker erratically or in some cases provide false readings.
This may also be caused by a faulty transmission speed sensor. The speed sensor reads the rotational speed of the reluctor wheel, located within the transmission. The speed sensor also controls the anti-lock braking system. Driving with a bad speed sensor usually causes the ABS to malfunction and can lead to loss of braking power and/or an accident. When this is not working properly, you may also notice the transmission hesitating to shift gears, erratic tachometer readings, the speedometer not working properly or the odometer not working properly. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.
Battery and oil light come on when trying to start car, take keys out try again car starts no problem and lights go away
ANSWER : Of course, don’t switch gears without being fully stopped, unless your Owner’s Manual or the manufacturer has alternative advice. However, the gear shift issue has no relation to the no-start problem you are describing. Inasmuch as you only have 6,000 miles on the car, the "constant on and off" that you believe has occurred is meaningless in comparison to the expected total vehicle service life. That is, assume what you perceive as "constant on and off", during merely 6,000 miles, might be equivalent to using the car "normally" for three years. A new car should be trouble free for at least 5 years, unless there is a defect, so your "constant on and off" is not a causal factor for any fault on the vehicle. What you might have is a defect in the ignition switch, or perhaps the immobilizer system, but if the problem is not in the switch itself, clearly there is an electrical problem.
If your vehicle is under warranty, by law the dealer MUST repair the issue you are describing within a prescribed time frame and number of "attempts", otherwise the dealer will run afoul of Federal and state Lemon Laws that give you very specific rights, and recourse (contact an Attorney; we are Mechanics, NOT attorneys). Consequently, if the vehicle is still under warranty, to save yourself money do be sure to seek a resolution from the dealer. If the vehicle is not under warranty, obviously a certified Mechanic from YourMechanic could identify the electrical fault and resolve this for you. If you want to go that route, please simply request a no start diagnostic -electrical system and the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.
