I thought I'd share my experience with this great tool for the diy group. I used it on a non-MB but the diagnostic process is virtually identical for the Benz. I'm not affiliated with the company and I don't sell them, just a user review.

Our 2011 Silverado 5.3 (106k miles) has had a slight intermittent misfire for a long time. No CEL and not bad enough to stall or impact driveability, but still a noticeable bump at idle, you can see tach shift around a bit. I got tired of it and decided to do some investigation rather than start buying parts hoping for a fix.

• I started with a visual inspection, found some of the plastic wire loom was brittle from heat cycles. The wiring was fine so I simply installed new loom. No other obvious issues.
• I cleaned the throttle body and installed a new gasket as well. Also cleaned the MAF sensor. Air filter was new.
• This truck has CNP Coil Near Plug (MB has COP) - I had installed new plugs at 90k miles along with new plug wires (very short wires). The plugs were installed as normal maintenance and didn't really impact the slight miss. The miss seemed to happen at operating temp (closed loop).
• I ran some real-time scan data and observed the short and long term fuel trims, the O2 sensor readings and the MAP/MAF readings in particular. This is a key step as it can help point you towards a failing O2 sensor or vacuum leak, both of which will impact the fuel trims. In this case all readings were normal. If there was a vacuum leak, it would typically result in rich fuel trims at idle which would normalize as engine speed was increased. Fuel pressure was also within spec. I also figured fuel injectors were functioning well as the fuel trims did not indicate any fluctuations. So I figured air and fuel were ok at this point.

I started thinking about ignition. I don't have a picoscope to observe detailed ignition function but after some research I decided to get the GTC 505 analyzer.
Here's a couple of videos on it:

I took the GTC 505 and used the coil sensor on each of the coils. I was also able to use the HOLD function to retain each reading on the screen to compare all 8 cylinders to each other.
On a cold or recently started engine, all graphs showed normal. But as I drove the truck awhile and then re-tested all coils I hit paydirt. Coil #6 showed a noticeable drop in its secondary voltage reading. In other words, you could see the primary voltage ramp start off ok but then deteriorate slightly as the coil became heat-soaked. I then swapped this coil with another cylinder and the voltage discrepancy followed the coil. I also used the spark plug sensor on the plug wires and verified that any plug connected to that #6 coil was impacted by the drop in voltage. It was actually more of a voltage breakdown, but still resulted in a noticeable drop and what I considered to be the cause of the miss. I replaced that single coil and the misfire is no more! Just for grins I also used the spark plug probe on the control wire to each injector and the 505 showed the voltage pulses. This tool also automatically sets up the chart reading range limits which is nice, all readings therefore are contained within the screen.

I think for the cost (I paid $238) it's an excellent addition to the home workshop. Think about diagnostic shop costs and it doesn't take long to make it worth buying. My intent is to put a bit of an investment into tools that will help me diagnose most of the usual issues that are faced. I realize that there may be cases above my pay grade and that's ok. I do have the MB icarsoft scanner, a Konnwei 850 obd 2 scanner and I also ordered an Autel MD 808 Pro. This gives me 2 out of 3 scanners which can access vehicle modules, not just basic obd2 1-4 modes.

Comes in a carrying case:



Here's the tool turned on, you can see the primary selection menu of how to look at readings. It comes with a USB charger, flex shaft and 2 end sensors (coil and plug wire):



Here are the 2 sensors, the one on the grommet is for coils, the one on the wire is for plug wires:



All in all, I am really pleased with the usefulness of this tool, and like the title says - big thumbs up!

 

I like where your workshop is heading. If you want to keep this car, these tools will pay for themselves really soon plus you get the satisfaction of solving your car issues yourself.

 

I think that these will be a great addition related to about any vehicle we have, or will have.
My next acquisition will be a Hantek 1008C PC Oscilloscope - I want to be able to look at CAN wave forms on both the high and low speed bus, along with various voltage readings during operation. Example is that you can compare injector pulse voltage to battery voltage draw during cranking to help isolate a cylinder misfire issue. Or compare crank/cam sensor readings, especially critical on vehicles with cam phasers.
I've got all of the more usual stuff like fuel pressure tester, compression tool, spark tester, voltage probe/multimeter, etc. but I'm interested in getting into more of what to me is the more complex stuff. Very straightforward to someone like DiagnoseDan on youtube, but I'm inspired to learn.

 

Mud, thanks for the review. This looks like an interesting tool.

 

I use my 500 for tuning chainsaws also . One of the best pocket tools for simple trouble shooting.

 

This is a very good tool Mud. Thank you for bringing it up.
Even say a scanner can read a command for ignition pulse, that is on the low voltage side of the coil, the input.

This GTC505 reads the high voltage side of the ignition coil or the output.
I am curious, well noted that depending on where we place the GTC505 sensor on a COP and how deep* ( *far away from sensor ) is the high voltage ( secondary ) coil side, how does GTC505 actually define the KiloVolt voltage value ?
This is basically like a non contact voltage detector, but it is a meter instead with supposedly KiloVolt value.

I will email them and ask on how accurate is their 6.4 Waveform view , for the kilovolt value. Page 10. https://gtc.ca/pdf/manuals/GTC505EMN1906EN.pdf
I think it is a "mathematical" value based on typical known secondary side of the coil voltage output and since it is a non contact, it must be the secondary side magnetic pulse magnitude the sensor is reading.
I dont know the proper name to call their "mathematical" value, but it can't be real kilovolt value , probably not even to +-20% accuracy, very unlikely.
We need a contact type divider probe like this to get voltage reading that high https://www.fluke.com/en-id/product/...s/fluke-80k-40

Nevertheless, I agree, this is a must have tool based on the videos of what it can do.

 

Hi S-P, here's some observations, now that I've had and used this tool for a while.
All in all, it has proved its worth in finding several bad plug wires and 2.5 bad coils I'll explain...

I've found that placement of the coil probe just above where the plug wire attaches or directly centered on direct coils has yielded very consistent results. I've compared the reading to mfg spec and it has been consistent, when the coil is good. In cases such as our 2011 Silverado 5.3, I can also check the plug wire using the U-shape plug wire probe. My hobby is resto-mod stuff so I've also used it with success on conventional (older) ignition systems such as HEI and points-type ignitions. The ability to switch to digital, graph or comparison views plus seeing the burn time are great features for this inexpensive tool.

One key feature to me is the ability to see/record one cylinder, then move to the other cylinders and also store/record them, allowing for a comparison of all cylinders. So even if you're not certain of what the voltage spec is per coil, you are still able to quickly see whether all coil voltages are close to each other or if there is one coil not playing well with the others. I mentioned 2.5 coils - I found bad individual coils in 2 vehicles, and this was verified with use of scantool to see cylinder misfire data. Yes, you can certainly switch coils to verify but this tool allows you to do an initial diagnosis in 5 minutes.

On the ".5 coil" this was on our Silverado recently. I saw a very slight misfire on cylinder 2, which is front right bank on the engine. By slight I mean less than 10 misfire count, then back to 0, but you could occasionally feel a slight bump and the tach would nudge slightly. Most would probably ignore it. Fuel injector pulse width and duration was checked via scantool - that was fine. I used the GTC to compare all coils and found that the coil on #2 had a slight inconsistency on the voltage level and burn time. AHA I thought it's a bad coil so I swapped it with another cylinder and then re-checked. However, the pattern remained on that same #2 cylinder with the swapped coil. Turns out the answer was in plain sight. The alternator charge cable was laying right on that #2 coil. When I moved the cable away from the coil the inconsistency stopped and so did any misfires. No parts needed. Evidently the cable interfered with the coil.

For me this GTC is a very good diagnostic aid, fit for my budget and purpose. I would love to have a Pico scope but the Hantek has worked fine for me, so it's all relative to my needs and amount of use.
There are never enough tools though .....

 

Sweet info Mud, thak you very much on the 0.5 fault info
You meant alternator charged wire as in the POSITIVE cable... correct ?
I assumed the alternator ground is engine metal diretcly and not isolated type alternator requiring stand alone negative cable.

So a current of say 80 amps from your alternator, its magnetic field proximity was interfering with the low voltage side ( primary ) of the #2 coil, interesting.
Is yours the 4 wires type ? https://opensiuc.lib.siu.edu/cgi/vie...text=auto_pres
I think for some reason the alternator wire at high amperage created a bogus 5 volt ECM command pulse to the COP ..

You know I have not actually messed with today's modern ignition. My last messing around was when we still use spinning distributor ... LOL.
I was more into yacht diesel engine after that spinning distributor era.

Why I was so keen to know how many KiloVolts this GTC505 can really read based on non-contact was actually the itchy hand part of me.
I sometime go to places where they have 20KV/400V transformer feeding the building. We are a 3 phase 230/400V 50hz country. We are 230V single phase 2 wire excluding ground/earth/PE, unlike USA 110/220 single split phase.
So I was just thinking to read voltage value non-contact on the main 20kv wires hehehe, that was the naughty idea.
I dont want to get closer than 40cm to the 4 terminations of the 20Kv on the transformer, but I dont mind playing a bit with the main wire before they split to 4 cores.

Thanks again for the experience sharing, will keep that in mind.

 

Yes, that's the positive lead from alternator to battery, alternator case grounded through attachment to engine. As far as I recall it's a 2-wire connector.
I didn't film it or anything but I could physically pull that positive lead away from the coil and observe coil reading settle down; letting the lead rest back on the coil caused the reading to get erratic. Repeatable confirmation.