A digital tachometer is more precise and shows the engine speed in actual numbers rather than looking at the needle. It looks like a digital clock. You might see a number like 2,000 or 2,147 on the display.
A low number like a 1 or 1. 3 on an analog or digital display can indicate a problem with the tachometer.
The manual will probably tell you to start by checking the fuse for the tachometer. If it’s blown, that’s likely what’s wrong with the tachometer. If you feel comfortable doing so, you can change the fuse yourself. Pick up a new one at an auto parts store or order one online. If you are handy, you can use the manual to find the tachometer and check it out for yourself. Take a look at the wires on it. If they look frayed, damaged, melted, or burnt, the tachometer probably needs to be rewired. Call a mechanic if you need a new tachometer or wires. It’s always best to get an expert’s help. If you have some experience with automotive, you can try replacing the wires yourself first. Check an auto parts store to get the parts you need.
Follow the directions in the manual for the handheld tachometer to it attach to your engine. Turn on your motor and rev your engine so that it reads 1,000 RPM on the handheld device. If your engine tachometer is within 10% of the same reading as the handheld device, your tachometer works fine. If it’s outside of that range, you need to call a mechanic or try to troubleshoot the problem yourself.
Locate the tachometer probe (again, consult your manual) and insert it into the multimeter. Rev your engine. If the tachometer reading and the multimeter reading match (or are within 10% of one another), it’s working properly. [8] X Expert Source Audra FordinCertified Automotive Technician Expert Interview. 13 January 2022. If not, it’s time to troubleshoot. If you have absolutely no idea what you’re doing, call a friend for help or contact a mechanic. It’s okay to not know! It’s also possible that the tachometer isn’t the problem. If it tests okay, let the mechanic know you’ve already checked out that possibility. Describe the problem to them so that they can check your car or boat for other issues.
Don’t worry if the needle or digital reading goes up dramatically if you speed up quickly. It will adjust as your speed adjusts. Most tachometers show a “red zone” that indicates you’ve revved your engine too much. This typically happens when your RPM is 7,000-8,000. If you hit that area of the gauge, slow down.
