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Editor/Blog Designer: Roger Young
E-mail: roger@northwestvets.com

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Electronic Diagnostics

In December 2015, we purchased a Snap-On Vantage Ultra to up our electronic diagnostic capability. As the cars have advanced with more electronic components, we felt it was essential that we have the testing capability to be capable of running lab scope tests on the various components.

The Vantage Ultra has the capability of testing virtually any automotive electrical component and features a high-speed 2-channel lab scope and graphing meters. You can test everything from fuel injector amperage draw, rise time and pulse width, electric motors such as fuel pumps, fan motors and relays, switches, charging system including alternator ripple tests for open/shorted diodes, parasitic draw, ignition scope patterns (coil, plug wires, sparkplugs), ignition pickup patterns (both distributor and crank triggers), and amperage draw/voltage patterns of any electronic component, oxygen sensors, MAF sensors, crank/cam sensors, ABS sensors – the list is endless with the available optional accessories.

It is our hope that by testing the individual components in our cars, we can find potential problems before they show up on the track.

Snap-on has a video on the meter here and we’ve added snapshot patterns of various component testing, including MSD pickup and spark patterns below.

We also have a separate page devoted to MSD Troubleshooting. – Roger

VantageUltra_lg

 

Fuel Pump patterns:

Pattern showing Paul's fuel pump when first turned on, with amp spike initially

Pattern showing Paul’s fuel pump when first turned on,
with clean amp spike initially

 

Fuel pump motor pattern on Paul's Mustang

Fuel pump motor pattern on Paul’s Mustang showing 3.2 amp draw
and the good condition of the pump motor!

 

57 Fuel Pump Motor

57 MagnaFuel Pump Motor

 

Notice the MagnaFuel pump on our ’57 and Chevelle pulls nearly 3x the amperage as Paul’s Mallory pump shown above on this page. This graph above shows the high volume pump is drawing 9.5 amps vs the 3.2 amps of the Mallory street/strip pump. 

 

Ignition patterns:

Spark firing line from Pam's S-10, conventional electronic ignition

Spark firing line & coil oscillations from Pam’s S-10,
conventional GM electronic ignition

 

Firing line & coil pack pattern on 3.3 V-6 with distributorless ignition

Firing line & coil pack pattern on 3.3 V-6
with distributorless ignition

 

The following two patterns are from Paul’s Mustang with the MSD 6AL ignition. The upper photo captures four cylinders showing 4 to 5 sparks per cylinder for approximately 6ms, compared to the 2ms firing line shown above in Pam’s truck with the GM electronic ignition. The second photo below shows the MSD magnetic pickup pattern.

With the Snap-On Shop Stream software you can see all eight cylinders in a streaming video on your computer.

MSD secondary pattern showing 4 cylinders

MSD secondary pattern showing 4 cylinders

 

MSD pickup pattern showing three cylinders

MSD pickup pattern showing three cylinders

 

MSD 7AL-2 pattern, '57 Chev

MSD 7AL-2 pattern, ’57 Chev

 

Electric motors:

57 Cooling/Water Pump Motor

57 Cooling/Water Pump Motor

 

Below is using the basic multimeter function, showing only amp draw using the optional low-amp probe:

57 Headlight/Running Light Draw

57 Headlight/Running Light Draw

 

Charging System:

Pam's S-10 charging voltage and amperage test displayed. This shows the charging voltage is fine, but that the internal regulator is far too sensitive with a very wide range of amperage, from 3-amps to 43-amps. This indicates a coming alternator problem.

Pam’s S-10 charging voltage and amperage test displayed.
This shows the charging voltage is fine, but that the internal regulator is far
too sensitive with a very wide range of amperage, from 3-amps to 43-amps.
This indicates a coming alternator problem.

 

Alternator ripple pattern from Pam's S-10

Alternator ripple pattern from Pam’s S-10
shows the condition of the alternator diodes

 

Mass Airflow Testing:

Most cars with port injection have a mass airflow sensor (MAF). Below is a MAF frequency pattern off my Buick 3.3L V-6 at approximately 1500 RPM, which is good. When testing a MAF sensor, tap on it LIGHTLY while viewing the pattern which will commonly show a defective sensor by indicating a major dropout and a miss in the engine.

MAF

 

This handheld diagnostic tool allows us to see & capture images & complete data streams of problems that were once only available to a professional technician working in a shop with a $35K scope, such as the one we had in our shop and used before I retired.

Plus this tool is portable, updates can be downloaded online, and it allows us the capability for detailed testing in the field.

 

Roger Young, retired
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