Use Your “Ignition Inner Child” to Resolve No Spark Diagnosis
As noted in this article by Andrew Markel on UnderhoodService.com, in the old days, no spark conditions were solved relatively easily by throwing some parts at the problem. But, with modern ignition systems driven by any number of modules, resolving these complaints has grown more difficult as systems have increased in complexity. That spells the need to adopt new approaches as these systems evolve.
Markel suggests that it is important that technicians retain their curiosity and a learning mindset. “Sometimes, your curiosity has led you in the wrong direction and cost you time, or it has led to a comeback. But, hopefully, your curious inner child is still growing, fueled by new knowledge and experience. The most important thing to feed your inner child is information to ask questions that form a proper diagnostic procedure.”
In keeping with a common theme in these articles, he suggests that technicians start with a good wiring diagram, understand the theory of operation for the vehicle under service and lean into your service information in order to solve these cases effectively and efficiently. He notes that ignition system design can vary greatly by manufacturer, such that a one size fits all repair strategy likely will be ineffective. He also provides examples of how quick fix diagnostic tricks could be more harmful than helpful. It’s a nice, brief and insightful look at this area of service.
Addressing F-150 No Crank / No Start Issues
Now, we move from no spark diagnosis to no crank / no start conditions on late model (2017-2020) Ford F-150s, with a quick primer on UnderhoodService.com. The article first identifies expected customer complaints stemming from this problem as well as the trouble codes that could be set. The article then narrows its focus to trouble codes related to network communication issues that can appear in relation to a no crank / no start on these vehicles (U0140, U0155, U0253, U0401 and/or U0452).
The article prescribes a diagnostic routine that starts with a first step inspection of the TCM, its connecting harness and all related grounds. It then lists out an additional five steps, depending on what is found in step 1. These steps include assess the operation of the Transmission Range Sensor and a battery reset procedure. Considering that this (no crank / no start) complaint is one of the most common vehicle issues seen on the popular passenger vehicle in the US, this article is a great bookmark candidate for future reference.
What About a Diesel No Start?
The factors involved in the starting event on a diesel vehicle are quite different than those of a gasoline powered vehicle. But, our old friend Pete Meier from VehicleServicePros.com says that shouldn’t scare techs away from servicing these vehicles with no start complaints. In this edition of The Trainer, Pete digs into diesel no start diagnosis.
First, he walks through the components involved in the diesel starting event as well as the operating process involved in these systems. He then demonstrates a quick test that can be done with a scope to ensure that the vehicle has consistent compression across all cylinders. He goes on to explain the critical role that the battery plays in proper diesel ignition performance – many of the operational steps are dependent on an adequate supply of power, which means that insufficient voltage can significantly impact ignition performance.
Then, he connects a scan tool and reviews all of the relevant codes and messages in key areas related to drivability and the ignition system. He identifies the ones of greatest relevance to the problem at hand and how he would move on to follow-up testing of those particular functions. For someone looking to gain a greater understanding of diesel starting and the diagnostic process related to it, this episode provides a great introduction.
Alternators and No Start
As we have discussed in previous articles, the starting system is like a 3-legged stool, where the legs of the stool are the battery, the starter and the alternator. A problem with any one of these components can quickly create knock-on problems in the other two. Proper alternator function is critical to the starting event because of the alternator’s direct impact on battery State of Health (SoH) and State of Charge (SoC). A successful start can only be achieved when the battery has enough reserve capacity and sufficient voltage to power the starting event.
This article, by Andrew Markel on UnderhoodService.com, provides a comprehensive look at modern alternator function, the factors that impact alternator function and testing techniques for proper alternator assessment. He starts by contrasting the way it used to be (basic electrical systems with simple alternator output expectations) with the way it is today (complex systems with computer-controlled alternator output dependent on a variety of inputs). He breaks down alternator operation (speed, belt slippage) and identifies how it could be easy to misdiagnose a low battery condition, for instance assuming inadequate alternator output when in fact the root cause is a parasitic draw. He finishes with testing tips. It is a great breakdown of this critical component.
Honda Voltage Problems
We’ll wrap up with a quick TSB highlighted on AutoServiceProfessionals.com. This TSB addresses potential customer complaints on a variety of 2016-2017 Honda vehicles. As noted, “While driving, the customer may experience flickering interior/exterior light, multiple indicators coming on, jerky steering and/or other voltage-related fluctuations.”
This one is a nice complement to the alternator article referenced above. The TSB outlines a repair procedure for these situations. It’s a relatively simple fix, but if you’re not aware of it, you might end up replacing parts unnecessarily. Another good one for a bookmark, considering the popularity of these vehicles.
Your Friend in the Fight
No start diagnosis is no easy task. But, equipping yourself with quality tools can help you tackle these challenges more effectively and efficiently. One critical tool in this fight is a quality battery and system tester. The SOLAR BA327, Digital Battery and System Tester with Integrated Printer, tests a wide variety of 6 Volt and 12 Volt vehicle battery types, including Flooded, AGM, Spiral Wound, Gel Cell, Start-Stop AGM and Start-Stop EFB batteries. It also provides the ability to test the starting system and charging system (12V/24V).
The BA327 is packed with features to deliver accurate analysis. It utilizes micro-load technology and temperature compensation to ensure that each battery tested is done so with precision. It provides battery pass/fail assessment and a numerical result of battery health (based on any of a number of available testing criteria – CCA, DIN, JIS, EN, IEC), along with an IR value, which allows fleets and other captive service environments to track battery health over time.
The BA327 also delivers convenience and efficiency for today’s shop. It features 10’ cable reach, allow the operator to easy access the testing points of vehicles of any shape or size. It has an adjustable backlit screen, allowing clear viewing in all environments. It features multiple languages and has a counter that tracks the number of battery tests and system tests performed, enabling the shop to ensure the tester is being used consistently. It is packaged in a handy storage case and ships with batteries, paper and side post adapters.
Have you ever faced a really difficult no spark or no crank situation that had you stumped?
How did you solve it and how did that impact the way you handled these situations from that point forward? Do you have any go-to diagnostic steps you’d like to share with our readers? We love to hear about it in the comments below.