Normally, I would cover anything related to the use of ANY Oscilloscope over at THIS Link:
https://gmtnation.com/forums/threads/how-to-use-pico-2204a-hantek-1008c-oscilloscopes.20423/
But with a contemporary issues in Recent Threads involving a P0014 (and a P0016) as well as a P0306, THIS Video affords Us THE PERFECT Opportunity to Answer the Question:
“Can We Diagnose our COPS (Coil Over Plugs) AND Our EFIs (Electronic Fuel Injectors) at the SAME Time, WITHOUT HAVING TO REMOVE ANYTHING FROM A RUNNING MOTOR? ...Right at the Power Distribution Center?"
Yup…! (Well... Perhaps One, Little Fuse...) :>)
And HERE is WHY…
Take a look at THIS Partial Diagram (Screen Print) of the GM 4.2L LL8 PCM-to-Engine Bus Harnessing for the COPs and the EFIs. Notice how they SHARE A COMMON POWER SOURCE ONLY ON THE PINK WIRE(s)?:
Next … We can observe how they ALSO Share Only One Fuse in the Power Distribution Center:
Fuse #28
So… If We remove Fuse #28 and transpose in a 'Fuse Buddy' (Red Wire Loop) with a 15 AMP Fuse installed…
We can encircle the Red Wire Loop with a Low Amperage 'Amp Clamp' and after Plugging the Tool’s BNC Connector into any Open Channel of ANY Oscilloscope (No Attenuator Required)
... and after "Zeroing Out" the Amp Clamp, We can then read the Wave Forms as Low Amperage Draws (Converted as Voltage Over Time to Amps within the Software and by making the correct Tool Selection) and Discover:
"What is Happening?"
within the Pink Wire(s) leading from the PCM to ALL of the COPs and ALL of the EFIs at the same time:
Now… by looking at the Combined Wave Forms on Screen:
...We can see that the Taller Spikes represent the COPs Firing Line:
....We can also see a Missing Tall Spike along the Firing Line of the Coil Over Plugs:
...and if you look at the Shorter, adjacent Spikes... We can identify WHEN the EFIs are Firing:
….and since we have a P0306 Code… Have a Look at THIS Image and Count the Sequence 1-6:
As you can see… We can instantly observe The Absence of a Primary HV Spike at COP #6...but perhaps even MORE Important is that:
NOW We Know WHY our Catalytic Converter gets SO DAMNED HOT and Why we will soon have to Replace it if We Do NOT solve "The Riddle of The Misfires".
And So… After Replacing the Inoperative COP… Please Observe the "Known Good Coil On Plug - EFI Oscilloscope Wave Form" for the GM 4.2L LL8 Engine Below:
Finally... We can Clear the P0306 Code with NO RETURNS as now, the Engine Runs Smoothly.
Please Observe the Source Video for this Pictorial Training Story:
And if anyone can think of a Better Way to perform these Combined COP & EFI Diagnostics on a Running Engine...By ALL Means...Do Add Those Ideas to This Thread! :>)
Automotive Oscilloscope Diagnostics... FTW
https://gmtnation.com/forums/threads/how-to-use-pico-2204a-hantek-1008c-oscilloscopes.20423/
But with a contemporary issues in Recent Threads involving a P0014 (and a P0016) as well as a P0306, THIS Video affords Us THE PERFECT Opportunity to Answer the Question:
“Can We Diagnose our COPS (Coil Over Plugs) AND Our EFIs (Electronic Fuel Injectors) at the SAME Time, WITHOUT HAVING TO REMOVE ANYTHING FROM A RUNNING MOTOR? ...Right at the Power Distribution Center?"
Yup…! (Well... Perhaps One, Little Fuse...) :>)
And HERE is WHY…
Take a look at THIS Partial Diagram (Screen Print) of the GM 4.2L LL8 PCM-to-Engine Bus Harnessing for the COPs and the EFIs. Notice how they SHARE A COMMON POWER SOURCE ONLY ON THE PINK WIRE(s)?:
Next … We can observe how they ALSO Share Only One Fuse in the Power Distribution Center:
Fuse #28
So… If We remove Fuse #28 and transpose in a 'Fuse Buddy' (Red Wire Loop) with a 15 AMP Fuse installed…
We can encircle the Red Wire Loop with a Low Amperage 'Amp Clamp' and after Plugging the Tool’s BNC Connector into any Open Channel of ANY Oscilloscope (No Attenuator Required)
... and after "Zeroing Out" the Amp Clamp, We can then read the Wave Forms as Low Amperage Draws (Converted as Voltage Over Time to Amps within the Software and by making the correct Tool Selection) and Discover:
"What is Happening?"
within the Pink Wire(s) leading from the PCM to ALL of the COPs and ALL of the EFIs at the same time:
Now… by looking at the Combined Wave Forms on Screen:
...We can see that the Taller Spikes represent the COPs Firing Line:
....We can also see a Missing Tall Spike along the Firing Line of the Coil Over Plugs:
...and if you look at the Shorter, adjacent Spikes... We can identify WHEN the EFIs are Firing:
….and since we have a P0306 Code… Have a Look at THIS Image and Count the Sequence 1-6:
As you can see… We can instantly observe The Absence of a Primary HV Spike at COP #6...but perhaps even MORE Important is that:
NOW We Know WHY our Catalytic Converter gets SO DAMNED HOT and Why we will soon have to Replace it if We Do NOT solve "The Riddle of The Misfires".
And So… After Replacing the Inoperative COP… Please Observe the "Known Good Coil On Plug - EFI Oscilloscope Wave Form" for the GM 4.2L LL8 Engine Below:
Finally... We can Clear the P0306 Code with NO RETURNS as now, the Engine Runs Smoothly.
Please Observe the Source Video for this Pictorial Training Story:
And if anyone can think of a Better Way to perform these Combined COP & EFI Diagnostics on a Running Engine...By ALL Means...Do Add Those Ideas to This Thread! :>)
Automotive Oscilloscope Diagnostics... FTW