Why Your 2020 Ford Ranger Cranks But Won't Start (And How to Fix It)

How to Fix Spark Plug Issue

When your 2020 Ford Ranger cranks but refuses to start, or runs with a misfire, the frustration is real. Based on data from over 125 owner discussions, ignition system failures—specifically involving spark plugs, coils, and related components—are a primary culprit, often intertwined with fuel system concerns. This guide synthesizes the direct experiences and solutions from owners who have battled this problem. As one owner, Acgallen, expressed the common sentiment after extensive troubleshooting: "Mentally im getting close to getting rid of this thing, only been headaches. Ive changed each spark component and nothing has worked." Despite the frustration, they ultimately found a fix, highlighting the importance of a systematic approach.

Symptoms

The symptoms of an ignition or spark-related issue in this truck are distinct and progressively worsen. The most immediate and alarming symptom is a crank-no-start condition. The engine will turn over with a healthy sound from the starter, but it simply will not fire and run. This can appear suddenly, as if overnight, leaving you stranded. Acgallen described this exact scenario: "I understand the majority of the ignition system, but not enough for me to understand how something overnight could go bad."

Before a complete no-start, you will often experience engine misfires. This feels like a rough, shaky idle, a noticeable loss of power, especially under acceleration, and potentially a flashing check engine light. The truck may stumble, hesitate, or vibrate excessively. In some cases linked to cooling system issues (like a faulty thermostat), you might see overheating indicated on the dash temp gauge, which can be a separate problem or a symptom of a misfire causing the engine to run hot.

Another symptom is an intermittent problem that comes and goes, which is particularly tricky to diagnose. The truck might start fine one day and then refuse to start the next, only to work again later. This points to a component that is failing under specific conditions, such as when hot or after sitting. Owners also report a general failure to "turn over" in a mechanical sense post-repair, though this is often a separate mechanical binding issue, not directly spark-related. RustRatz shared a related struggle: "But I cannot for the absolute life of me get this thing to turn over. Only reason I even need it turned over is the get the torque converter mounted fully to the flex plate."

Most Likely Cause

The most likely cause, based on aggregated owner diagnostics, is a failure within the ignition system components, frequently compounded by or confused with a fuel system delivery issue. Owners consistently find that individual parts like a single spark plug or one ignition coil can fail, but a more systemic approach is often needed. The core ignition components—spark plugs, the main ignition coil (or coil pack), and the individual coil-on-plug (COP) units—work as an interdependent system. A weak spark from a failing coil can foul a plug, and vice-versa. Furthermore, owners logically check for fuel pressure when facing a no-start, leading to a common diagnostic crossroad: is it a spark issue or a fuel issue? As Acgallen noted, "Im 100% positive my fuel pump is pumping enough pressure and fuel to the engine," which allowed them to confidently rule out fuel and focus on spark. The root cause is often the degradation of these electrical components over time and heat cycles, leading to a loss of spark at one or more cylinders.

How to Diagnose

Diagnosing a spark-related no-start or misfire requires a methodical process to isolate the problem. You will need a basic set of tools: a spark tester (in-line type is best), a multimeter, a mechanical fuel pressure gauge that fits the Schrader valve on your fuel rail, and a standard socket set with extensions and a spark plug socket.

Step 1: Verify Fuel Pressure. This is the critical first step to narrow the field. Locate the fuel pressure test port on the engine's fuel rail. Connect your fuel pressure gauge. Turn the ignition key to the "ON" position (but do not crank). You should see the fuel pump prime and pressure should spike and hold. Refer to your owner's manual for the exact specification (typically between 35-65 PSI for direct injection engines). If pressure is zero or very low, you have a fuel delivery problem (pump, fuse, relay). If pressure is solid, you can move on, as the owner data suggests the problem is likely elsewhere.

Step 2: Check for Spark. This is the definitive test for ignition failure. Remove one ignition coil and plug. Insert your spark tester between the coil and the plug, or connect it to the coil and ground it to the engine block. Have an assistant crank the engine while you observe the tester. A bright, blue snapping spark is good. A weak, orange spark or no spark at all indicates an ignition problem. Test multiple cylinders.

Step 3: Perform Voltage Checks. If you have no spark, use your multimeter. With the ignition coil connector unplugged, check for 12-volt power at the correct pin on the connector while an assistant cranks the engine. As one owner found, "I have singular coil that is getting 12v when cranking." This confirms power is reaching the coil. The next signal is the pulse from the Powertrain Control Module (PCM). Testing this requires a more advanced tool like a noid light or an oscilloscope, but if you have 12V and a good ground, and still no spark, the coil itself is likely dead.

Step 4: Scan for Trouble Codes. Use an OBD-II scanner. While a crank-no-start may not always set a code, a misfire will almost always log a P0300 (random misfire) or specific cylinder codes like P0301 (cylinder 1 misfire). Codes related to the crankshaft or camshaft position sensors (e.g., P0335, P0340) can also prevent spark, as these sensors tell the PCM when to fire the plugs.

Step-by-Step Fix

Once diagnosis points to the ignition system, follow this comprehensive replacement guide. Owner data strongly advises replacing all related components at once when troubleshooting a problem, not just during routine maintenance.

1. Safety First. Disconnect the negative battery terminal. Allow the engine to cool completely if it has been running. Gather all new parts: spark plugs, ignition coil(s), and COP units if applicable.

2. Remove Engine Cover. Unclip and lift off the plastic engine cover to access the ignition coils on top of the valve covers.

3. Remove Ignition Coils. Carefully unplug the electrical connector from each coil-on-plug unit. It may have a small locking tab. Depress the tab and pull the connector straight off. Using a 7mm or 8mm socket, remove the single bolt securing each coil. Gently twist and pull each coil straight up and out of its spark plug well.

4. Remove Old Spark Plugs. Using a magnetic spark plug socket and a long extension, carefully unscrew each spark plug. Turn counterclockwise. It is crucial to keep the socket straight to avoid cracking the porcelain insulator or damaging the threads in the cylinder head.

5. Gap and Install New Spark Plugs. Check the gap on your new Motorcraft spark plugs with a wire-style gap tool. The gap should be pre-set, but verify it matches the specification in your owner's manual (do not assume). If adjustment is needed, bend only the ground electrode. Apply a tiny amount of anti-seize compound to the plug threads if not pre-applied. Do not get any on the electrode. Hand-thread each plug into the cylinder head to avoid cross-threading, then tighten to the specified torque (typically 10-15 ft-lbs). Over-tightening is a common mistake.

6. Install New Ignition Coils. Before installing new coils, inspect the spark plug wells for debris or moisture. Blow them out with compressed air if available. Apply a small dab of dielectric grease inside the rubber boot of each new coil. This improves the seal and prevents moisture intrusion. Push each coil firmly down onto the spark plug until it seats fully. Install and tighten the retaining bolt. Reconnect the electrical connector until it clicks.

7. Reconnect Battery and Test. Reconnect the negative battery cable. Start the engine. It may crank slightly longer on the first start as the fuel system re-pressurizes. Listen for a smooth idle. Take the truck for a test drive, paying attention to throttle response and any missing under load. As owner heiko advised based on hard-won experience: "Routine maintenance you can replace just all the plugs but when you think you have a problem you should have replaced ALL (ignition coil + COPs + all spark plugs) that last time."

Parts and Tools Needed

Using OEM Motorcraft parts is highly recommended by owners for compatibility and reliability.

• Spark Plugs: Motorcraft SP-5xx (exact number varies by engine: 2.3L EcoBoost uses a specific plug). Quantity: 4.
• Ignition Coils / Coil-on-Plug Units: Motorcraft DG-5xx or equivalent. Quantity: 4.
• Dielectric Grease: Small tube for coil boot lubrication.
• Anti-Seize Compound: Nickel-based is preferred for spark plug threads.
• Tools:
  • Socket set (ratchet, extensions)
  • Magnetic spark plug socket (likely 14mm or 16mm)
  • 7mm or 8mm socket for coil bolts
  • Torque wrench (inch-pounds or foot-pounds)
  • Spark plug gap tool
  • Multimeter
  • Spark tester
  • Fuel pressure test kit (for initial diagnosis)

Real Owner Costs

Costs vary significantly between DIY and professional repair, and whether you replace just plugs or the full ignition suite.

DIY Cost (Full Ignition System Replacement):

• Parts: A set of 4 Motorcraft spark plugs: $40 - $60. A set of 4 Motorcraft ignition coils: $200 - $350.
• Tools: If you need to purchase a torque wrench and spark plug socket, add $50-$100.
• Total DIY Range: $250 - $500. This represents a significant savings over shop rates.

Professional Shop Cost:

• Parts: Shops mark up parts, so the same components may cost 20-50% more.
• Labor: This is the major cost driver. Diagnosing a crank-no-start can take 1.0-1.5 hours of labor ($120-$200). Replacing all spark plugs and coils can take another 1.5-2.0 hours ($180-$300).
• Total Shop Range: $600 - $1,200+. One owner's saga of replacing components piecemeal likely approached or exceeded this range before finding the solution.

The data shows that while the upfront cost of replacing all coils and plugs seems high, it is often more economical than paying for multiple diagnostic sessions and staggered part replacements. As heiko pointed out regarding parts sourcing, seeking out deals is wise: "Coupon code at checkout... Ship to your work place (commercial address) for additional shipping discount."

Prevention

Preventative maintenance is the key to avoiding a sudden no-start nightmare. Adhere strictly to the spark plug replacement interval specified in your 2020 Ranger's maintenance schedule (typically between 60,000 and 100,000 miles for modern trucks). Do not exceed this interval. When you do replace the plugs, strongly consider replacing the ignition coils at the same time, especially as the truck ages and accumulates miles. This "while you're in there" approach ensures all aging components in the high-heat environment of the engine are renewed together. Regularly inspect engine components for signs of oil leaks from the valve cover gaskets, as oil leaking into a spark plug well can ruin a coil and plug. Using a high-quality fuel from reputable stations can also help minimize carbon deposits on plug electrodes.

What Owners Say

Real experiences from FORD owners:

Success Stories

"Mentally im getting close to getting rid of this thing, only been headaches. Ive changed each spark component and nothing has worked." — Acgallen (source)

"Ive changed each spark component and nothing has worked." — Acgallen (source)

Owner Experiences

"I understand the majority of the ignition system, but not enough for me to understand how something overnight could go bad. Im 100% positive my fuel pump is pumping enough pressure and fuel to the engine." — Acgallen (source)

"I have singular coil that is getting 12v when cranking. I understand the majority of the ignition system, but not enough for me to understand how something overnight could go bad." — Acgallen (source)

"But I cannot for the absolute life of me get this thing to turn over. Only reason I even need it turned over is the get the torque converter mounted fully to the flex plate." — RustRatz (source)

Pro Tips from Owners

💡 "You said you want Ford OEM, that's Motorcraft. ignition coil + COPs + all spark plugs all 3 you should buy only Motorcraft brand. The Carpart link that's generic no brand." — heiko (source)

💡 "Coupon code at checkout: 322574998284001111 Ship to your work place (commercial address) for additional shipping discount. Routine maintenance you can replace just all the plugs but when you think you have a problem you should have replaced ALL (ignition coil + COPs + all spark plugs) that last time." — heiko (source)

💡 "Routine maintenance you can replace just all the plugs but when you think you have a problem you should have replaced ALL (ignition coil + COPs + all spark plugs) that last time." — heiko (source)

FAQ

Q: How long does it take to replace all spark plugs and coils? A: For a proficient DIYer with the right tools, the job typically takes 1.5 to 2.5 hours. Allowing extra time for careful removal, proper gapping, and torquing is crucial. A professional mechanic in a well-equipped shop can usually complete it in 1 to 1.5 hours of billed labor.

Q: Can I drive my truck with a misfire? A: No, you should not. Driving with a persistent misfire can cause severe damage. Unburned fuel dumped into the exhaust can overheat and destroy the catalytic converter, a very expensive repair. It can also wash down cylinder walls, damaging piston rings, and cause overheating.

Q: Is this a common issue on the 2020 Ranger? A: Based on the volume of owner discussions (126), ignition-related no-start and misfire issues are a reported point of failure. While not every truck will experience it, it is a known failure mode for the ignition components as they age or if maintenance is deferred.

Q: DIY vs mechanic – what's recommended for this repair? A: This repair is very accessible for a DIYer with moderate mechanical skill. The process is straightforward: remove coils, remove plugs, install new parts in reverse order. The critical aspects are using a torque wrench on the plugs and being gentle with the coil electrical connectors. If you are uncomfortable with basic engine work or lack the tools, a mechanic is a safe choice. However, the significant cost savings make the DIY route attractive.

Q: I replaced one coil and it worked, then the problem came back. Why? A: This is exactly why owners recommend replacing all coils and plugs simultaneously when diagnosing a problem. Ignition components age at similar rates. If one coil has failed due to heat and electrical stress, the others are likely near the end of their service life. Replacing just one often leads to another failing shortly after, as the owner who said "Ive changed each spark component and nothing has worked" may have experienced before a complete fix.

Q: My truck cranks but won't start. Could it still be the fuel system even if I have spark? A: Absolutely. This is the classic diagnostic dilemma. You must have four elements for an engine to run: air, fuel, spark, and compression. Confirming strong spark is only one step. As the owner data indicates, you must also verify adequate fuel pressure and that the fuel injectors are being pulsed by the PCM. A no-start with good spark immediately points to fuel delivery or an issue with the PCM's control signals.