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I have spark, fuel and compression but no start

I have spark, fuel and compression but no start

Gap spark plugs are a critical part of your engine. They allow air and fuel to mix, creating the power that makes your car go. But what about when they go bad? You need a qualified mechanic to diagnose and fix your gap spark plugs so you can continue using them safely and efficiently. With proper care, gap spark plugs can last for years without the need for service.

When you have spark, fuel, and compression but no start, it’s probably because your piston rings are bad. Piston rings are what keeps the air and fuel in the chamber so it can combust. The good news is that replacing them is pretty simple. So, what can I do when I have spark, fuel, and compression but no start?

First, you will want to drain your oil and remove the valve cover. This will give you access to the top of the cylinder head and the camshafts. Remove as many parts as you need to get to the piston rings. For most cars, this means removing the intake manifold, timing belt and chain, front cover, water pump, and harmonic balancer pulley.

Piston rings are a crucial part of an engine, which is why it’s important to keep them in good working condition. If one of your piston rings is damaged, it can prevent your car from starting or running properly. A damaged piston ring can also cause other engine problems, including damage to the engine block and oil leakage.

I have spark, fuel and compression but no start

Why have I got a fuel pressure but no start?

Not having the car start when it should be frustrating, especially if you have fuel pressure.

You can check fuel pressure at the rail using a gauge or by turning your key and watching the needle on your dash. If it doesn’t read within the manufacturer’s specifications, you may have a bad fuel pump, filter, or regulator. You likely won’t get a check engine light for this kind of problem until later down the road.

So, to check fuel pressure, you will need a Fuel Pressure Gauge Kit. Using this kit is easy: just install the gauge in the fuel line after removing the gas cap. Turn your key and watch the pressure readout on the gauge. If it doesn’t fall within manufacturer specs, then you likely have one of three problems: bad fuel pump/filter/regulator.

To fix this, you will need to either replace or clean your fuel filter.

How to replace the fuel filter?

Replacing a fuel filter in your car can seem intimidating, but it’s really not so scary. It’s something most people can do successfully with a little help from their manual and a couple of basic tools.

Here’s how to change your fuel filter:

  1. Locate the fuel filter in the engine compartment and loosen the clamps that hold it in place.
  2. Gently pull the end of the hose off of the fuel filter, then repeat on the other side.
  3. Remove the old filter and replace it with your new one. Be sure they’re facing opposite directions—the arrow on your new filter should be pointing toward your engine, which is also where both ends of the hose should be attached to their respective ports.
  4. Tighten those clamps back up.
  5. Start your car to make sure your new fuel filter is working properly and you are good to go.

How to clean fuel filters?

To clean your car’s fuel filter, you’re going to follow these easy steps:

  1. Disconnect the negative battery cable.
  2. Unscrew the fuel filter’s retaining screws and pull it away from the fuel line.
  3. Pry apart the retainer rings of both ends of the filter and carefully remove them.
  4. Remove the element inside the filter and discard it.
  5. Soak a new element in gasoline for 15 minutes before reinstalling it, then reattach the retaining rings and screw on the new filter.
  6. Carefully reconnect the fuel line, making sure that you secure it tightly but do not over-tighten it (this will prevent leaks).
  7. Reconnect the battery cable and start your car to make sure everything is running smoothly.

What sensors can cause a car not to start?

If your car doesn’t start, it could be because of any of these sensors:

1. ABS sensor

ABS stands for the anti-lock braking system. The sensors detect any sort of skidding, allowing your brakes to respond appropriately. If this sensor is faulty or damaged, it may prevent your car from starting altogether.

The most common type of ABS sensor is a wheel speed sensor.  There are four on each car, and they’re all located on either side of the rear axle, near the wheels. If you have trouble starting your car and find they’re covered in dirt or mud, clean them off and see if that does get things going again.

2. Barometric pressure sensor

The barometric pressure sensor determines the air pressure in the tank. This is how the car knows how much fuel is in the tank and sends this information to your dashboard. It also helps with more advanced operations like starting up the engine when it’s cold outside.

When the air pressure outside is low, more oxygen can enter the combustion chamber during the combustion process. As a result, more air and fuel can be mixed together, and therefore you get greater fuel efficiency.

However, if this does not happen, starting problems may arise, such as rough idle on cold startups or engine stalling (rough idling). Because of that, automakers are now responding to these problems by returning to a less sophisticated air flow meter in order to reduce costs.

3. Camshaft position sensor

The camshaft position sensor, also called a magnetic pick-up, tells the car’s computer how far your valves are open. This information is sent to the engine control module (ECM).

The ECM gets this information from the camshaft position sensor and tells the electronic fuel injectors how much fuel to put into the cylinders when you start your car.

If there is a problem with the camshaft position sensor, the computer will not get the correct information from it, and the car may not start.

4. Engine coolant temperature sensor

An engine coolant temperature sensor is a device used to monitor the temperature of the engine coolant in an automobile. A car will not start if there is a problem with the sensor through the wiring that connects it to the engine management computer or the computer itself.

5. Intake air temperature sensor

If your car turns over and has a spark but still will not start, it could be an intake air temperature sensor. This is the sensor that senses how hot the engine is to determine if it is too cold or too hot to start.

6. Knock sensor

A knock sensor transmits a voltage signal to the engine control module (ECM). This enables the ECM to modify the ignition timing and prevent engine damage due to knocking. When this sensor is faulty, the timing of the vehicle’s engine will be incorrect and automatically shut off. This can lead to the vehicle not starting.

Can a blown a fuse cause a car not to start?

Yes, a blown a fuse can cause your car not to start. Fusible links and fuses protect wiring from power surges and overheating.  If the connection point becomes corroded or rusted, you may blow a fuse if trying to start the car.

When a fuse is blown, your vehicle’s electrical system is shut down, and you’ll experience failures of the components that depend on that circuit. If there’s no power to necessary systems such as fuel pumps, air conditioning, and windshield wipers, it’s likely due to a blown a fuse in your car.

Can a 02 sensor stop your car from starting?

A Faulty 02 sensor can cause your car not to start. This can be very frustrating for any driver.

The 02 sensor is responsible for monitoring the air-fuel mixture inside the engine chambers and relaying information back to the computer, which then either adjusts fuel flow rates or ignition timing depending on what area the sensor reports is requiring more attention.

Your oxygen sensor will not stop your car from starting. It may, however, cause your car to stall or run poorly while you’re driving, so it’s important to replace it regularly.

Also known as the O2 sensor, this little guy measures the amount of oxygen present in your exhaust. It then sends that information to your car’s computer so it can adjust the fuel-to-air ratio.

If the O2 sensor isn’t working properly, it won’t be able to tell if there’s too much or too little oxygen in the exhaust and won’t be able to make any adjustments to help keep your engine running smoothly.

So if you notice a rough idle or other signs of poor performance, such as reduced gas mileage or trouble accelerating, check your O2 sensor first, and it may just need a replacement.

Can mass airflow sensor cause no start?

Yes, the mass airflow sensor is responsible for measuring the amount of air entering your engine. Because it affects the air-to-fuel ratio in your engine, bad readings from the MAF sensor can cause your car to stall or not start.

The MAF sensor has a delicate wire that can easily be damaged by dirt, dust, or debris. A dirty MAF sensor will give incorrect readings to the computer, and it can cause stalling or no-start issues.

Your MAF sensor may also need to be replaced if it’s damaged by a rear-end collision or if you’ve been driving through extremely deep water.

Can you clean a fouled O2 sensor?

You can clean a fouled O2 sensor, and you should. A fouled sensor is generally caused by oil or coolant leaking onto the sensor and contaminating its ability to measure oxygen levels in your exhaust. Cleaning a fouled sensor is actually pretty simple:

  1. Remove the faulty O2 sensor from its location on the exhaust pipe
  2. Use a wire brush or sandpaper to lightly sand the exterior of the sensor
  3. Wipe away any grit with a cloth (make sure it’s clean)
  4. Reattach the O2 sensor to the exhaust pipe
  5. Take your vehicle for a drive to confirm the authenticity of the work you did.

Lexus won’t start but has power.

If your Lexus won’t turn over, but the dashboard lights and other electronics work normally, then the problem is most likely due to your battery or one of the connections that are located in the starter circuit.

The first thing to check is the battery. You can do this by testing for power at both of the battery terminals. If you have power at both terminals, then your battery is OK. If you have power at only one terminal, then you probably have a bad battery.

If it shows power at both terminals, then you should check all of the connections to the starter and solenoid. If these are loose, corroded, or damaged in some way, this will affect your ability to start your car.

The next step is to test for voltage at the starter solenoid control wire. This usually requires removing a wire from one of the terminals on the starter solenoid and inserting a voltmeter probe into it while someone attempts to start the car.

If you get voltage on this wire while attempting to start the car, then most likely, you will need to replace your starter motor.

Car won’t start after a new battery installed

Your car won’t start after installing a new battery because there is something wrong with the alternator.

The alternator generates power for the engine and electrical systems. When the alternator is not working correctly, it will eventually drain the car’s battery.

If your car does not start after installing a new battery, try charging your battery for at least two hours before trying to start your car again. If it still does not start, you will need to have your alternator replaced.

Honda civic won’t start but has power

If your Honda Civic won’t start but has power, you may have a problem with your starter. The starter is the part of your car that gets everything going: it’s what makes the engine turn on so you can get moving. A problem with the starter means a problem with your whole car.

It’s normal for there to be some trouble starting every now and then, and the first time you try to start your car in the morning, it might take a second or two to get going.

But if this is happening all the time, or if it seems like there’s no power getting to the engine at all, it’s time to go to a mechanic and have them check out the starter.


I have spark, fuel and compression but no start, and what could be the cause? We have the right answer to the question on this page. There are several reasons that could happen, and we have taken the whole time to explain in detail what you can do.