I have a good battery but my fuel pump is bad. if I get a boost off will the car crank?
my dashboard lights come on but when you turn the key on over it doesn't crank.
My car has 217812 miles.
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
Hi there. You could try to jump start your car, but if the fuel pump is broken, the added electricity will not help. A car will not start for multiple reasons, ranging from a damaged fuel pump, bad battery or battery cables, faulty ignition system component or a bad starter. It’s probably a good idea to have a professional mobile mechanic come to your location and complete a car is hard to start inspection first, to determine what is causing this issue, so the right repairs can be made.
How to Identify and Fix Common car Problems ?
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Electrical issues: Electrical faults are also significant contributors to fuel pump failures. The most common electrical issues are rusted connectors, loose connectors, or melted wiring and connectors.
As you may know, the fuel pump does in fact receive power from the battery, however it is highly unlikely that the fuel pump would continue to run when the power to the car is off causing the battery to drain.
Dead car battery: A dead battery is the most common reason why a car won`t start. If you have a battery tester, check your battery to see if it`s weak. If you don`t have one, try to jump start your car with jumper cables.
The ignition circuit, which includes the ignition switch, controls power to many components, including the fuel pump and relay. If there is an issue with the switch or the circuit, perhaps a wiring problem, then power to the fuel system may be cut off.
Irregular resistance within the fuel pump motor can lead to your car slowing down and being unable to accelerate. Failing to accelerate is a good sign that your vehicle`s fuel pump needs inspection.
A Bad Crankshaft Position Sensor
The crankshaft position sensor monitors the position and rotational speeds of the crankshaft. Without the crank sensor, the engine control module (ECM) wouldn`t know when to fire the fuel injectors and ignite the spark plugs.
One of the easiest ways to determine if the lack of fuel may be the cause of a non-starting engine is to spray some aerosol carburetor cleaner directly into the throttle while the engine is being cranked. If the engine starts, runs a few seconds and dies, it has spark and compression but is not getting any fuel.
The throttle position sensor (TPS) is usually connected to the throttle plate shaft in the throttle body. The TPS reads the angle of the throttle valve and transmits an electrical signal to the PCM. The PCM uses this real-time signal to help calculate or modify fuel injector pulse width, controlling air/fuel mixture.
Electronic Control Unit (ECU)
The ECU is the brain of the operation. It uses engine RPM and signals from different sensors to meter the fuel. It does this by telling the fuel injectors when and how long to fire. The ECU often controls other functions like the fuel pump and ignition timing.
The most common reason a pump fails is wear on the pump from improper lubrication or over-use. The best way to explain a failed fuel pump due to wear and tear is to explain what other reasons may have lead to a failed pump: Most fuel pumps are lubricated by the fuel in the tank itself.
Because fuel pumps constantly run whenever the ignition is turned on, they can eventually wear out and weaken over time. A weak fuel pump may still pump fuel, but the vehicle may experience difficulty starting from the lack of pressure.
A voltage of at least 12.5 – 13.0 volts must be present when the engine and pump are running. If the measured voltage at the terminals or the plug of the pump is significantly lower than the on-board voltage, e.g. lower than 11 volts, there is a malfunction.
It is also important to note that if you drive a car with a bad or dead alternator, you run the risk of damaging critical electrical components such as the water pump, power steering, and fuel pump.
Bad Fuel Pump, Fuel Pressure Sensor Can Trigger `Check Engine` Light, P0087 Code. Your car`s “Check Engine” or “Service Engine Soon” light can flash on for more than 1,400 different reasons.
If the fuel pump relay has an issue while the vehicle is operating it will cut off power to the fuel pump, which will cause the engine to stall. A faulty relay may allow the vehicle to be restarted a short while later, while a completely failed relay will not.
The electric fuel pump on a vehicle with a spark ignition engine is controlled by a fuel pump relay. The engine control module (ECM) activates the relay when operating conditions are correct. For safety purposes, the fuel pump relay is only activated when an engine speed signal is received by the ECM.
If either due to a faulty crank sensor, or ecu, the crank sensor signal is not being read, the ignition and fuel pump systems will not power up.
A camshaft position sensor is an electronic device that does what it suggests — monitor the camshaft position and speed — and feeds that data to the vehicle`s engine control module (ECM). The ECM needs this data to control how much fuel enters the combustion chamber and ignition (spark) timing to ignite the fuel.
Bad Spark Plug Or Broken Distributor Cap/Rotor
If you have a good battery and enough fuel in the gas tank and your car still won`t start, chances are you have a bad spark plug. Why? A bad spark plug will prevent fuel ignition, and the vehicle won`t move.
If there is no sound when you turn the key, but the lights and accessories work, it could be the stater relay or starter solenoid. However if there is no sound at all, not even a click, it`s probably your battery.
Fuel pump failures tend to be sudden and unpredictable, with few symptoms to warn the motorist that trouble is brewing. And the higher the mileage on the vehicle, the greater the risk of a fuel pump failure.
Electrical issues: Electrical faults are also significant contributors to fuel pump failures. The most common electrical issues are rusted connectors, loose connectors, or melted wiring and connectors.
By itself, a high-flow fuel pump will not increase power, but it will provide the ability to increase power by providing a higher flow of fuel to the engine when major engine upgrades are performed.
Look into the fuel pump to see the filter, which will look like a screen. Don`t try to remove the filter, but instead use a clean paint brush to sweep away any debris blocking the filter. You can dip the paint brush in new gasoline to make it easier for the debris to stick to the bristles of the brush.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
Just replaced my fuel pump but its not getting any power tested fuel pump relay and fuel fuse both good tested the wires all good.
ANSWER : You need to look at the theft light on dash to make sure it comes on and goes off when you turn the key to the on position. If light comes on and stays on then your theft system is causing the fuel pump to not be engaged. I recommend you check the theft system and then scan the computer for theft system codes. You may need to reprogram the keys to work or you have an bad sensor for the ignition key in the steering column.
Car sounds like its not getting fuel cranks normal. Fuel pump is working. Fuses and relays good. crank no start. No codes
ANSWER : Hi There,
Try starting the car and if it does not start, turn the key off and then pull one of the spark plugs out to see if it is wet with fuel. If the spark plug is dry, then you know you have a fuel supply problem. If the spark plug is wet with fuel, I would suggest next checking for spark issues such as a failed ignition coil. Ignition coils are prone to randomly failing and causing the car to not start without warning as you describe. I would suggest having a professional from YourMechanic come to your location to take a look at your vehicle.
Try starting the car and if it does not start, turn the key off and then pull one of the spark plugs out to see if it is wet with fuel. If the spark plug is dry, then you know you have a fuel supply problem. If the spark plug is wet with fuel, I would suggest next checking for spark issues such as a failed ignition coil. Ignition coils are prone to randomly failing and causing the car to not start without warning as you describe. I would suggest having a professional from YourMechanic come to your location to take a look at your vehicle.
Car is not getting fuel. I changed fuel pump and checked the fuel pump relay. It was in good condition. What else could it be?
ANSWER : This may likely be related to the fuel pressure regulator. This is a unit that helps to maintain the fuel pressure in the system. When this is not working, this may cause an erratic fluctuation in the fuel pressure or in some cases, no fuel pressure at all. If you’d like assistance with this repair, I would recommend having an expert from YourMechanic come to your location to diagnose the issue firsthand and service your fuel pressure regulator as necessary.
Car want start unless boosted, alternator good and battery good, while boosted the car crank in the key off position.
ANSWER : You should request a starter circuit diagnostic to get this resolved. If you want to attempt to diagnose it yourself, first perform a load test on the battery just to be sure that the battery is not an issue. If the battery happens to be discharged when you attempt that test, suspect a parasitic current draw in your car’s electrical system which is depleting the battery while the car is off, thus making it impossible to start the car at next use. If the battery does pass a load test and yet there is no starter operation with the key held in the "start" position, the procedure is to test for power and voltage drops to the starter motor/solenoid. If there is no power, or a large voltage drop is measured, then the electrical circuit supplying the motor has a fault. That circuit begins at the battery and includes grounds, wiring (some of which is very heavy cabling), fuses, relays, the ignition switch, neutral start switch, and terminations. Basically, with a fully charged battery, and with the key held in the "start" position, the starter is either getting power or it isn’t. With the key in the "start" position, if the starter motor is getting power but the starter doesn’t work, then the starter is condemned and replaced. Note that starters can and sometimes do develop intermittent faults due to bad spots on the armature. The bottom line is if there is battery voltage to the starter (and no excessive voltage drop) and yet the starter doesn’t work, it’s dead. If you want these steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request a starter circuit diagnostic and the responding certified mechanic will get this taken care of for you.
With regard to the power steering issue, in 2014 GM recalled many vehicles, including your model, to address problems with the power steering system. Depending on the vehicle GM was to replace either the power steering motor, the steering column, the power steering motor control unit or a combination of the steering column and the power steering motor control unit. You should check to see if the required repairs were made on your vehicle but, if not, whether you are still eligible. If you are not covered for the repairs, YourMechanic will diagnose and resolve the issue for you if you request a power steering warning light diagnostic. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.
Car will crank but no start… Fuel pump not coming on. New pump, relay, etc. Will start when hot wire runs from pump wires to bat
ANSWER : There are a couple of approaches to take here – either start from the battery and work "towards" the fuel pump, fuse box, ignition switch, fuel pump relay, and wiring connections in between. Or, as you have done, start at the pump with 12v, and move backwards towards the battery. This will require a GM service manual, or wiring diagram at least, with connection locations as well.
I would recommend having a certified technician from YourMechanic diagnose this starting issue, get an accurate assessment of damage and cost estimate for repairs. YourMechanic.com can dispatch a mobile, professional mechanic to your location for this repair.
Engine crank, no coil spark, fuel pump does not kick in.
ANSWER : Hi there. There could be multiple issues causing your lack of spark problem, ranging from a minor electrical short in the main relay to an issue with your ECU. In order to know for sure, you should have a professional mobile mechanic complete an electrical problems inspection.
I changed the fuel pump in my car thinking that it was the problem, but I’m still not getting power to my fuel pump.
ANSWER : If there is access to a wiring diagram, you can disconnect the fuel pump harness and install a test light in between the power and ground circuits and turn the key to accessory or try to start the vehicle and if the test lamp lights up, the circuit is not the problem and you may have picked up a faulted new fuel pump. IF you can hear the fuel pump power up and there is no fuel pressure at the fuel rail, the fuel filter may be clogged. Consider hiring an experienced technician like one from YourMechanic who can come out for a closer inspection of the vehicle to run a few tests and offer a more personal diagnosis of your fuel system concerns.
the car is acting like its getting to much fuel. changed the fuel pump, fuel filter, and the fuel pump relay.
ANSWER : There could be a few things contributing to your problem. You are correct that clogged or sticking fuel injectors and possibly the fuel pressure regulator could be faulty. A plugged catalytic converter can also cause the vehicle to bog down. A failing throttle position sensor can cause the symptoms you describe as well. I suggest having a certified technician, like one from YourMechanic.com, do a few tests to determine the exact cause of your starting concern.
