Amp clamp test for spark

[23 CHIEF]

Can a amp clamp on a multimeter be used to check if an engine is getting spark

 

[tamaraw]

You don't need any tools for that. Simply remove the plug from the cylinder head but leave it connected to the lead/coil. Set it so that the threaded portion grounds against something solid (ex: cylinder head, block, accessory bracket, etc.). Then crank the engine over with ignition power on; if there is spark, you will see it. You can also see the color and relative strength.

You may want to disable your fuel system (ex: pull injector/pump fuse or drain the carb bowl) if you don't want it to actually start running.

If you are working alone and can't reach the ignition, you can jump power from battery positive to the starter solenoid. It also helps keep cranking time down to a minimum rather than yelling at someone else to start/stop with some inevitable delay.

An amp clamp is typically for measuring AC current, not checking DC voltage. Although I think they are sometimes used to help diagnose ignition coil issues on newer coil on plug setups, not too sure about that.

 

[milky2k]

No, I don't think you can. I've not seen this technique before and there may be a reason. Ignition coils are high voltage but low amperage, the amp clamp may not be sensitive enough to register an amount that low and that fast. Maybe it will flicker trying to show a measurement but if it can't register a value then it would be hard to compare the performance against the other spark plugs. Automotive oscilloscopes use amp clamps all the time to measure and graph spark performance but that is dedicated hardware for that purpose. A quicker test was mentioned above. You may also use adjustable spark plug tester like the one below to give you and idea of the spark strength based on the max gap the spark can jump. Many auto parts stores will carry something similar.

https://www.amazon.com/dp/B0014WDFLY/?tag=atomicindus08-20

Also, it just occurred to me that removing the ignition coil and/or spark plug for the tests described above also gives you the chance to visually inspect the components and look for issues that stand out right away- worn boots, carbon tracking, oil, crud, etc in the spark plug cylinders.

 

[zendriver]

And inductive timing light works great.

Add ignition produces extremely low amperage so it’s doubtful that the clamp will work

 

[richfinn]

I just use an incandescent test light connected to ground for a basic spark check and either disconnect a HT lead/ or pull the coil out and see if the spark will jump a 10mm gap (approx) at the business end.

You can measure ignition coil primary current with an amp clamp/oscilloscope combo

Depending what type of ignition system your looking at there are multiple methods of testing for spark such as inductive probes for coil on plug.

 

[tamaraw]

Also, it just occurred to me that removing the ignition coil and/or spark plug for the tests described above also gives you the chance to visually inspect the components and look for issues that stand out right away- worn boots, carbon tracking, oil, crud, etc in the spark plug cylinders.

Exactly. Even if an amp clamp were able to indicate power on a spark plug lead, it wouldn't show if the color is orange (weak), if the plug is fouled, if the electrode is simply fubar, etc.

 

[lilredex]

Make up something like this...

 

[rockettauto]

Can a amp clamp on a multimeter be used to check if an engine is getting spark

Yes, but not a typical meter.

Needs to be a low current dc amp clamp.

Like such

https://www.amazon.com/dp/B094R6QMCZ/?tag=atomicindus08-20

In fact I'm not even sure if that one has the reaction time to show it. But it is kinda cool and I might have to buy it.

This meter will for sure, as will anything with inductive tach. Like has already been suggested, a timing light .

LCD Automotive Multimeter with Tachometer Kit

Amazing deals on this Lcd Automotive Multimeter With Tach at Harbor Freight. Quality tools & low prices.

www.harborfreight.com