If when you turn the key the engine turns over normally but will not start, there can be any number of reasons for this problem.

Some basic checks will need to be done to diagnose this problem.

1. Do you have fuel pressure.

Some cause of low or no fuel pressure are a plugged fuel filter, faulty pump relay, blown fuse, bad fuel pump. Different makes and models require different fuel pressures to start. Refer to a manual for the proper pressure for your application.

2. Is there sufficient spark at all the spark plugs.

No spark can be caused by many things. A faulty sensor, computer, ignition module, etc. Spark on some spark plugs can be caused by faulty ignition coil, spark plug wires or the plugs themselves.

3. Do the injectors fire and spray fuel into the engine.

No "Fuel Injector Pulse" can be caused by a faulty computer, wiring, or a computer. Pulse can be tested with a special test light. If the test light blinks, then the injector should fire. If not, then a plugged or failed injector is the cause. There are several special tool / tests to check the injector system.

4. Is the engine mechanically capable of starting.

Checking the internal components of the engine is required. Check for compression, see if the internal parts such as the Camshaft are turning, etc. There are also many tools to do these tests.

Question: Car cranks but wont start or stay running. Changed sparks plugs,coils ,crankshaft position sensor, camshaft senor.

Answer: You need to tell us what make and model vehicle you are asking about. This could be many different things wrong with your vehicle, and some are make and model specific. In general, you need to know if you are getting spark and fuel. Just changing all these parts does not help since we don't what the engine is missing.

If you have spark, then you need to find out if you have fuel pressure and fuel injector pulse signal. If no fuel pressure, there could be a bad fuel pump. If no fuel injector signal, this could be a bad PCM. Is the theft or security light on? If so then that is where your problem is.

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Comments (31)
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  • Guest - Melissa d Norris

    2004 ford e450 v10 class c motorhome.... cranks but won't start...we have 1. Changed the crankshaft sensor 2. changed the PCM 3. Camshaft sensor 4. Replaced the fuel Pump 5. Replaced the computer (again) 6. changed the ignition switch 6. checked the Mass air flow sensor. Have also check relay , fuses and wires.
    we have placed Noid light on Fuel injectors... it will flash ONE time only when cranking, until you turn the key off and do it again, then repeats the one time only. any Ideas????

  • Guest - rick

    2004 buick rendevoue starts cold when hot cranks but wont start intermittently no spark

  • Guest - Miranda Price

    I have a 1999 murcury Tracer that will crank but want stay running . its not fuel pump or regulator changed filter its getting spark checked all plugs and wires bought a new battery. And my check engine light has never came on. Could someone please throw out any new ideas I can try

  • Guest - Bruce

    Have a 2006 Buick Rendezvous 3.5 motor fuel pumps running fuel pressure it's good new plugs new wires no fuel coming out of return will not crank

  • Guest - Anna

    I have a 2001 Ford F150 Super Crew Lariet. I have replaced the Battery last week, but it tries to start and then does nothing, then I wait a few minute's and do it over again, sometimes it starts and other times I doesn't. Don't want to be taken advantage of because of being a woman, need to know what direction to go in

  • Guest - Rick

    I have a Buick Allure 2005 will not start. Installed new fuel pump checked fuel relay. The fuel pump is not turning on. Car cranks over no problem will run till all fuel is out of the fuel line then cranks but no fire. I can tell the fuel pump is not running. But changed it anyway. Nothing on the diagnostics. Can't find any electrical break but have not traced wires all the way to the fuel pump. Any help??

  • Guest - Jack

    In reply to: Guest - Rick

    You need to check for power and ground to the pump to decide what side of the circuit to diagnose. Purple wire should be hot, black should be ground.

  • Guest - John

    02 Monte Carlo no injector pulse 3400

  • Guest - bob

    In reply to: Guest - John

    You need to determine if the problem with no fuel injector pulse is because there is no power feed to the injectors, or no ground side. A fuse supplies 12 volts to the injectors, the ECM control the ground side.

  • Guest - John

    No injector pulse

  • Guest - Megan

    I have a 97 Chevy suburban k1500 4wd 5.7 vortec I have checked all fuel module coil changed crank sensor and still not starting or getting spark what do I do

  • Guest - Timberly

    I have a 99 lesabre no spark were should i start is it possible the plate under the coil packs is bad

  • Guest - ProMechanic

    In reply to: Guest - Timberly

    It depends on what engine you have. If you have the 3800 V6, then the crank position sensor behind the crankshaft pulley is most common. If you have the 3400 V6, most common is the ignition module.

  • Guest - Gwen

    I have a 98' Buick Lesabre. It cranks but wont. I check the fuel pump,starter,battery,spark plugs. I wondering if its a sensor. Can someone give me advice.

  • Guest - Jimmy

    In reply to: Guest - Gwen

    Cranks but won't start here what sounds like an electrical shock coming from the glove compartment??

  • Guest - L. Denny

    2008 HHR - I don't know much about the history of this vehicle - as I'm looking into buying it off of a friend for a reasonable price. However - at first we thought the battery was completely shot. Took it to my shop - charged it, put it back in - engine now cranks - not will not start. We have absolutely no knowledge on this car or its specifications other than browsing the owners manual. I understand there are many fuses correlated with major engine (fuel) functions. What kind of tools are exactly needed to check these troubleshooting ideas? I'm not a mechanic. My husband isn't either. I can hear the fuel pump 'hum' when switching the key to 'on' position (but not cranking it). Can anyone help me with step by step instructions (for amateurs) on troubleshooting steps one by one? Thanks!

  • Guest - DeWayne

    I have a 2006 chevy hhr 2.2 i have no fire no injecter action and the security light gose ok as soon as it comes on.

  • Guest - Tommy

    Thanks for the info. Great site.

  • Guest - steven la fortune

    My 98 buick turns over fine but will not start got spark got fule every thing seems fine but np start dam it im going crazy help me please help me only 80 k on this car help me

  • Guest - joe

    [quote]07 Nissan quest wont start new crank and cam sensors and no fire on sparkplugs please HELP.

  • Guest - joe

    07 Nissan quest wont start new crank and cam sensors and no fire on sparkplugs

  • Guest - Stan

    In reply to: Guest - joe

    If there is no spark, maybe the ignition module went bad.

  • Guest - tim

    04 Buick lesabre turns over but will not start..fuel pump is working..there is fire coming the coil packs..though it does sound like the timing is or has jumped..

  • Guest - Techjk

    In reply to: Guest - tim

    Well, all an engine needs to start is fuel pressure, spark, injector pulse and compression. Check that the fuel pressure is good. Just becuase you hear the pump does not mean it has enough pressure. Timing chain may have jumped or broke. Check compression.

  • Guest - Ted

    That could be a million things Melissa. You need to find out if the engine has spark, fuel pressure and fuel injector pulse. Which ever one is missing, that system needs to be diagnosed.

  • Guest - melissa

    1998 chevy venture, cut off yesterday while i was at a stop light and will not start back. It turns over but wont start. what is wrong.

  • Guest - Alyss Washington

    In reply to: Guest - melissa

    Im having similar problem Melissa I have replaced ALTETNATOR battery fuel pump all that goes wit them IM HAVING NEW STARTER INSTALLED as well as wat goes wit it.. I'll bookmark and let u know if my 02 Chevy venture starts..... She tries to but JUS won't kick all way over

  • Guest - johnny

    2005 dodge stratus 2.7 cranks ok has fuel presher.neen steep by step. trouble shooting.

  • Guest - Tony

    In reply to: Guest - johnny

    Step by step? Ya, get a manual. Check for spark, if none, diagnose that system. Does it have fuel injector pulse signal? If not diagnose that system. Is the fuel pressure high enough? If not diagnose that system. Does the engine have an internal prolem like low compression from a timing chain that jumped? Diagnose that system. See a pattern here?

  • Guest - bob

    1998 Chevy Cheyenne 4x4 305 engine turns over but will not fire. Has fuel, started out being hard to start ondamp or wet days, then progressed to not firing at all. Suspect faulty coil or distributor. Please help if you can.

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