OTC 6589 Electronic Ignition Spark Tester - Simply Insert Into Spark Plug Wire Being Tested and Ground the Clamp then Crank/Start Vehicle and View Results

Excellent tool, I don't even consider using a screwdriver or additional spark plug to test coils, a real test anymore. Coils sometimes like to get weak over time, and cause occasional misfires. You can't really test if it's 20% weaker than its supposed to be. It will still appear to be a good spark. Unless you use the OTC spark tester, it requires the coil to output a much higher voltage. Similar to under high load conditions. Sounds like I'm trying to sell this tool, but it saved me a lot of time today on a Ford 5.4 with 4 coils that didn't pass on the tester. They all had decent spark but not enough apparently. Replaced all 4 of the ones that tested bad, and now it runs great. There's no other way I would have known that. The only issue I've had with it is the end that snaps into the spark plug wire kept unscrewing over time, a little loctite should keep it in place though. Also the porcelain can get dirty, I use brake cleaner and a clean paper towel or q-tip to wipe it clean again. I bought this about 2 years ago, it's helped me a lot but really saved me today. I paid $13.84 here on Amazon. Paid for itself over and over. Edit 2021: the clip fell off recently, since it's really only hung by a small metal tang. Problem is, the spring flew somewhere and now I can't use the clip anymore. In order to ground it, I have to attach a small jumper wire to it now. Which I had to do that occasionally anyway, since cars have so much plastic. I'll probably find another spring eventually, and cut it down if I have to.

I’m not a professional mechanic, but I pretend to be one. We’ve all done it before—using jumper cables or vice grips or any other means of grounding out a sparkplug to check and see if it has spark. Well, that’s basically what this thing is. I’ve only used it once (on a ’96 Toyota with coil on plugs) and it worked like a champ. I don’t know if the shape of the porcelain and the gap it has to jump affects how loud the “pop” of the spark is, but you don’t even have to see the spark to know it’s working—you can hear it. I know there are some comments about this unit not working with older style ignitions, but let’s be serious. If you’re working on a 65 Ford, you probably just hold the spark plug in your hand and crank the engine to see if it’s working. We’ve all done it….at least once to our little brother. It’s a little on the pricey side, but as long as you don’t drop it on a concrete floor or throw it against the wall, it should last you many years (or 100,00 miles, whichever comes first). Very happy with my purchase and I wouldn’t hesitate to buy again.

I own an automotive repair facility that employs 3 other technicians and I have been using spark testers for over 30 years and I have tried them all: 1. The plastic encapsulated ones (not reliable or accurate) 2. The "In Line" type - NEVER - NEVER USE THESE!! It only takes around 10,000 volts to "light" those up - but todays cars need upwards of 50,000 volts so you'll have a "light" but not enough volts to fire the spark plug. 3. I have had 2 OTC 6589's in my box for 20 years - they ALWAYS work AND tell the TRUTH! Yes, I have played around with the others and ALL OF THE DIFFERENT STYLES OF THE FIRST 2 I LISTED HAVE CAUSED ME TO MISS A DIAGNOSTIC. (Hence - cost me productivity time & money) But, when I am in doubt, I grab my OTC and PROVE IT! I NO LONGER USE OR ALLOW IN THE SHOP ANY OTHER SPARK TESTER THAN AN OTC. When I am diagnosing a V-6, V-8 or V-10 motor, I use 2 of these at the same time - one on each side of the motor. Sadly, I dropped one and it being porcelain - it broke (just like a regular spark plug would) So I just ordered 2 more today to keep in my shop. By the way--- the KD 2757 that "LOOKS" the same as the OTC one DOES NOT!!! They changed the design and it is now "plastic encapsulated" and not as accurate. (Same design as the KD 2756) Yes - the OTC is more expensive but this is truly a case of " YOU GET WHAT YOU PAY FOR!" Update: Something I forgot to mention - the clips on these are as heavy duty as they could make them with the amount of material they have to work with. I don't use the clips on the tester itself (yes, they break) I use a 3 foot jumper wire I made out of common "lamp cord" with alligator clips on each end. (it's flexible, heavy duty and rated for 25 amps) (also see: Kastar Hand Tools (KAS1138) 2 x 30' Magnetic Retractable Test Leads - 10 amp rating) I clip one end of the jumper wire to the spark tester clip and the other end to the CLEAN Negative post on the battery - not any metal on the engine itself. If you don't "KNOW" that you have a good ground (rust, corrosion, bad ground from battery to engine block) then you could make a false diagnostic not due to the spark tester operation but because you didn't have a good ground path for the current. Whenever I am testing electrical, I NEVER ground to the frame or body - I always run a jumper wire to the battery negative post - and make sure the negative battery post is clean!

This tester is nice. It doesn't break the bank and if you get spark you know everything is good. It takes the guess work out of having to measure the spark etc from other testers. If you don't get spark and you have it properly grounded you know something is wrong. I read a few reviews before purchasing this at least one of which complained about the spring mechanism that clamps the tester to said ground. Truth be told on my fist use YES it did come apart because the spring popped out but it is simply because the clamp is not very big and the spring has no real groove to rest in. IMO this is not an issue as it can be put back together VERY simply and does NOT break when this happens. In fact in my case I was testing the coil on a 2002 civic and it was difficult to get it clamped to any nearby ground anyway. It worked better without the spring and me just holding it. That said I gave it 4 stars for this reason. It can be a little hard to get it grounded depending on your car and style of engine. But all in all it worked flawlessly and was a quick way to diagnose my misfire. I would say on the next version maybe make a larger clamp connection or maybe include an extension for the ground. But all in all a great cheap device!

Chevy Vortec engines need special equipment like this to test the spark plugs. It is cheap and reliable. Remove the spark plug wire from the spark plug and install it on the tester's spark plug. Clip the clip to a reliable ground, preferably a wire connected to the battery negative. See the solid spark when the engine runs. Use the information gained to determine if you have problems in the ignition.

Tis only works if tou have spark plug wires. So you can see if you have a spark. I recently had a bad wasted spark problem and wanted to see if both sides of the coil were working. And this helped. I also did see the multiple spark problem with a scanner but still wanted to confirm this way. It can be used on older classics cars. (Hopefully we are talking about using on big block chevys)

Used on my ford to test weak coil packs worked great

The main "plug" of the tester works well for automotive coil, but the clip is poorly designed and constructed. First, the spring for it can move around and fall out (and get lost), which then allows the moving half of the clip to detach. Second, the other half of the clip which is welded to the plug body isn't terribly durable, and given the tester is designed to work by clipping to some solid ground point, it's pretty easy to break off if it's remotely knocked around.

His quality tool works amazingly for hei and dis systems and is a necessity

Excelente producto, muy útil

Hasta el momento lo eh usado una sola vez , cumple con su función .

This is a great spark tester. I used it to diagnose my ignition coils on an older car. Simple to use, and feels very sturdy. The one failing, which is mentioned in a lot of reviews, is the clip used for grounding it. It is simply too flimsy. Mine sheared right off the third or fourth time I used it! That said, I don't think the clip is necessary at all. The best way to ground it is to use your jumper cables. Much more convenient, and felt way more secure in use. Your engine cranking will tend to shake that little built-in clip right off the ground point. I would recommend this to anyone who maintains their own car. It is an inexpensive addition to your tool kit.

I do own several spark testers and own a Lisle one where you connect it to the coil and the top of the spark plug and a bulb lights when you have spark. I have found that the one i have it sometimes gives a false reading so have been lead down the wrong path. I was told to get this one so i ordered it but before even using the tool i noticed the spring clamp spot welded to the side doesn't look secure. I can see this breaking off with constant use but when i did use it the first time i can say this is a great spark tester even on vehicles today doesn't matter the age. It's simple to connect and sturdy. However, third time using the test, the clip used for grounding broke off. I was faced with two challenges, 1. to tack weld it back on or 2. use a jumper cable to ground it. Since i am not the greatest welder i went with option 2 as seems more sturdy for a ground method and now can used right off your negative battery cable. Just beware that it will take a little longer to crank the end and many shake a bit more and only run it for a few seconds. The clip is the weakest part of the tool and wish it was more sturdy otherwise i am happy and it does the job i need it to is check for spark as it's a sparky situation.