Really appreciate the run down. For anyone else trying to watch this and study for the ASE A1 - the answer they're looking for is put the clamp on the positive wire going to the starter. I'm not saying the negative is wrong - that's just what the ASE is looking for.
It really depends. On some vehicles it is a quick process to remove the fuel pump fuse. Many vehicles might tie in other systems to that same circuit. As a process, I review the electrical diagram and look for the quickest and easiest process.
Great video on relative compression test. It can indicate many failure modes that will not show on a scanner b/c of mechanical failure. In my opinion, best to use a fuel injector to identify a cylinder and then follow firing order. Too many older engines have wasted spark ignition on mirrored cylinders, so its a 50/50 guess on which cylinder to check for more diagnostics. Again, great video
It will. Any amp clamp with the correct range should work. You can also get similar (less pronounced) information with a oscilloscope measuring battery voltage.
So this test gives no actual compression read in terms of psi/kpa? But a wave form of "compression/ignition" (in amps?) That is used to give a relative idea of the entire compression state?
That is right, the test provides no actual compression data. The reading shows us how each cylinder is performing relative to another. It is a quick test help us understand if a misfire is compression related.
If I can hear/feel a limp while cranking, what is this test telling me that I don’t already know? At that point, I’m doing a compression test on all cylinders followed by a leakage test to get a full health report on that engine, to assure nothing is missed. I’m sure glad all these scopes weren’t around, and they weren’t shoving this garbage down our throats way back when I went to school
How does an electronic amperage test tell you anything about cylinder mechanical compression tho? I thought your wave form there only demonstrated spark (and combustion?) Or is the combustion itself signaling compression?
When compressions is present, the starter motor must work harder to continue rotating the engine. With an amp clamp, we can see these rises in current usage and equate them to compression events.
![Compression Test with a Scope [PicoScope, Autel MP408, Micsig, & Autel Ultra]](http://i.ytimg.com/vi/w8CyhpWXG5E/mqdefault.jpg)
![Compression Test with a Scope [PicoScope, Autel MP408, Micsig, & Autel Ultra]](/img/tr.png)
![FIND MISFIRES FAST! [How To Check Misfire PicoScope 2204A Automotive Diagnostics] Mechanic Mindset](http://i.ytimg.com/vi/MOLj5vGIDsg/mqdefault.jpg)
Really appreciate the run down. For anyone else trying to watch this and study for the ASE A1 - the answer they're looking for is put the clamp on the positive wire going to the starter. I'm not saying the negative is wrong - that's just what the ASE is looking for.
Thanks for watching and adding to the discussion.
Thank you Adam. Good job. Have a blessed and safe week to you and your family.
Thanks, you too!
Very clear and helpful. Thanks a lot
Glad it was helpful!
Just what I wanted to see .. you are a winner
Thanks for watching!
good clear demonstration, thanks
Thank you for watching!
Fantastic informative video thanks 👍
KNOWLEDGEABLE Adam 's Analysis
Tutorial very helpful 👌👏 👍thank you
Adam 's Analysis
From Nick Ayivor from London England UK 🇬🇧
Much appreciate your time, but unplugging the fuel pump fuse is more easier? Or depends?.
Thank you so much
It really depends. On some vehicles it is a quick process to remove the fuel pump fuse. Many vehicles might tie in other systems to that same circuit. As a process, I review the electrical diagram and look for the quickest and easiest process.
@@AdamsAnalysis bless you 🙏
Or remove the starter relay and crank it there
Great video on relative compression test. It can indicate many failure modes that will not show on a scanner b/c of mechanical failure.
In my opinion, best to use a fuel injector to identify a cylinder and then follow firing order. Too many older engines have wasted spark ignition on mirrored cylinders, so its a 50/50 guess on which cylinder to check for more diagnostics.
Again, great video
Thank you ❤
i have the hantek cc-65 amp clamp, will that work if i set it right?
It will. Any amp clamp with the correct range should work. You can also get similar (less pronounced) information with a oscilloscope measuring battery voltage.
So this test gives no actual compression read in terms of psi/kpa? But a wave form of "compression/ignition" (in amps?) That is used to give a relative idea of the entire compression state?
That is right, the test provides no actual compression data. The reading shows us how each cylinder is performing relative to another. It is a quick test help us understand if a misfire is compression related.
If I can hear/feel a limp while cranking, what is this test telling me that I don’t already know? At that point, I’m doing a compression test on all cylinders followed by a leakage test to get a full health report on that engine, to assure nothing is missed. I’m sure glad all these scopes weren’t around, and they weren’t shoving this garbage down our throats way back when I went to school
How does an electronic amperage test tell you anything about cylinder mechanical compression tho? I thought your wave form there only demonstrated spark (and combustion?) Or is the combustion itself signaling compression?
When compressions is present, the starter motor must work harder to continue rotating the engine. With an amp clamp, we can see these rises in current usage and equate them to compression events.
@@AdamsAnalysis thx this is really helpful and useful info.
Way to go adam
Thanks!
❤
nice
i have an ampclamp but not like this one ,KAIWEETS KC 601
Very expensive test ! picoscope + laptop .. the itester carscope is better and faster 🙂