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  • FIRST POST
    • mro
    • By mro 5th Jul 17, 7:05 PM
    • 595Posts
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    mro
    Difficult starting -checking Crank & Cam sensors
    • #1
    • 5th Jul 17, 7:05 PM
    Difficult starting -checking Crank & Cam sensors 5th Jul 17 at 7:05 PM
    Car is difficult starting first thing or after a period.

    Getting ECU fault codes for Crank & Cam sensors.


    Once it has started, maybe warmed up, it is running ok.

    Initially I had changed both Crank & Cam senors, car wouldn't start.


    So went back to old Crank sensor, still with new Cam sensor (as not easy to change this one back).

    So now car starts, but is difficult starting first thing or after period.


    Any ideas on testing Crank & Cam sensors & diagnosing this ?

    Thanks
Page 1
    • BeenThroughItAll
    • By BeenThroughItAll 5th Jul 17, 7:21 PM
    • 4,234 Posts
    • 3,565 Thanks
    BeenThroughItAll
    • #2
    • 5th Jul 17, 7:21 PM
    • #2
    • 5th Jul 17, 7:21 PM
    Car is difficult starting first thing or after a period.

    Getting ECU fault codes for Crank & Cam sensors.


    Once it has started, maybe warmed up, it is running ok.

    Initially I had changed both Crank & Cam senors, car wouldn't start.


    So went back to old Crank sensor, still with new Cam sensor (as not easy to change this one back).

    So now car starts, but is difficult starting first thing or after period.


    Any ideas on testing Crank & Cam sensors & diagnosing this ?

    Thanks
    Originally posted by mro
    Do you own an oscilloscope?
    • arcon5
    • By arcon5 5th Jul 17, 7:49 PM
    • 12,989 Posts
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    arcon5
    • #3
    • 5th Jul 17, 7:49 PM
    • #3
    • 5th Jul 17, 7:49 PM
    What was the actual error code and message
    • Alice Holt
    • By Alice Holt 5th Jul 17, 8:13 PM
    • 1,215 Posts
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    Alice Holt
    • #4
    • 5th Jul 17, 8:13 PM
    • #4
    • 5th Jul 17, 8:13 PM
    Could it be an old battery not spinning the starter motor to the necessary speed?

    Cold or Hot starting problems?
    • mro
    • By mro 5th Jul 17, 10:00 PM
    • 595 Posts
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    mro
    • #5
    • 5th Jul 17, 10:00 PM
    • #5
    • 5th Jul 17, 10:00 PM
    Do you own an oscilloscope?
    Originally posted by BeenThroughItAll
    No, just multimeter.
    • mro
    • By mro 5th Jul 17, 10:09 PM
    • 595 Posts
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    mro
    • #6
    • 5th Jul 17, 10:09 PM
    • #6
    • 5th Jul 17, 10:09 PM
    Could it be an old battery not spinning the starter motor to the necessary speed?

    Cold or Hot starting problems?
    Originally posted by Alice Holt
    That's what I thought, I knew in last few days my quite new battery, bought Dec 16, was getting iffy, wasn't holding charge or lasting when turning engine. Thought battery wasn't up to job, that its power/current was collapsing while turning engine. It is almost like the engine stops momentarily when cranking or misfires.

    So I changed/exchanged the battery yesterday, but still have problem starting first thing, starting when cold or after a period.
    • mro
    • By mro 5th Jul 17, 10:15 PM
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    mro
    • #7
    • 5th Jul 17, 10:15 PM
    • #7
    • 5th Jul 17, 10:15 PM
    What was the actual error code and message
    Originally posted by arcon5
    19 Incorrect Revs per Minute (RPM) signal (crankshaft sensor) Incorrect signal, check sensor

    92 Camshaft sensor Incorrect signal
    • BeenThroughItAll
    • By BeenThroughItAll 6th Jul 17, 1:46 PM
    • 4,234 Posts
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    BeenThroughItAll
    • #8
    • 6th Jul 17, 1:46 PM
    • #8
    • 6th Jul 17, 1:46 PM
    No, just multimeter.
    Originally posted by mro
    In which case, unless your multimeter has a pulse width function or frequency measurement function (which few do unless very high end or designed for automotive use) you'll be restricted to testing that the sensor has a resistance within the expected range, and unable to test that it is actually generating a waveform while the engine is cranked.
    • EdGasketTheSecond
    • By EdGasketTheSecond 6th Jul 17, 8:51 PM
    • 157 Posts
    • 78 Thanks
    EdGasketTheSecond
    • #9
    • 6th Jul 17, 8:51 PM
    • #9
    • 6th Jul 17, 8:51 PM
    Starting is most likely down to a deteriorated crank sensor. See if its resistance has gone higher than what it is supposed to be. Get a new one that actually works.
    • mro
    • By mro 6th Jul 17, 11:26 PM
    • 595 Posts
    • 612 Thanks
    mro
    Starting is most likely down to a deteriorated crank sensor. See if its resistance has gone higher than what it is supposed to be. Get a new one that actually works.
    Originally posted by EdGasketTheSecond
    At first I tried a new Crank sensor, but that did not seem to work, so I went back to my old Crank sensor, which was falling apart, wires shorting and I had to rewire.

    I returned the new Crank sensor to shop, which is being sent back to be checked and bought another one which I am trying, think 2nd one could be better, but not sure yet.


    I'm now wondering about compatibility issues and whether I need original Vauxhall sensors, as my car is 20+ years old from 1995.

    Problem is the new Crank & Cam sensors I bought were both showing in ECU fault codes, which does not bode well.
    • m_c
    • By m_c 7th Jul 17, 10:12 AM
    • 51 Posts
    • 28 Thanks
    m_c
    The fault codes could be symptoms and not faults, as some older Vauxhalls would show those faults whenever the engine was not running.


    Some vehicle detail would help.
    • mro
    • By mro 7th Jul 17, 11:36 AM
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    mro
    The fault codes could be symptoms and not faults, as some older Vauxhalls would show those faults whenever the engine was not running.


    Some vehicle detail would help.
    Originally posted by m_c
    It's a Vauxhall Cavalier 1995 2.0i CDX (X20XEV engine)


    I've put in another new Crankshaft sensor, but still getting difficult starting, although does seem better than previous new Crankshaft sensor I tried and have returned.


    The Camshaft sensor fault code strangely now seems to have disappeared for some reason.

    92 Camshaft sensor Incorrect signal ==>not getting this now
    • m_c
    • By m_c 7th Jul 17, 8:49 PM
    • 51 Posts
    • 28 Thanks
    m_c
    From what I remember, getting a crank shaft or camshaft sensor fault when the engine wasn't running was normal. They would disappear as soon as the engine was running.


    Personally, given your symptoms, I would be looking at the coolant temp sensor for the ECU. That failing would give the symptoms you describe. They had a habit of failing in a way the engine would think it was either hotter or colder than what it really was without triggering a fault, so fuelling would be wrong until the engine somehow started and entered closed loop mode. After which it would run fine.
    • AndyPK
    • By AndyPK 8th Jul 17, 7:21 PM
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    AndyPK
    Is it a Vauxhall 2.0 ?
    • AndyPK
    • By AndyPK 9th Jul 17, 9:35 PM
    • 2,113 Posts
    • 544 Thanks
    AndyPK
    cam sensors were very problematical on those engines.

    I think you get code 31 if its not running.

    Yeah I think the problem maybe else where.
    • mro
    • By mro 10th Jul 17, 12:55 PM
    • 595 Posts
    • 612 Thanks
    mro
    Is it a Vauxhall 2.0 ?
    Originally posted by AndyPK
    cam sensors were very problematical on those engines.

    I think you get code 31 if its not running.

    Yeah I think the problem maybe else where.
    Originally posted by AndyPK
    See post #12.

    It's a Vauxhall Cavalier 1995 2.0i CDX (X20XEV engine).


    The Camshaft sensor fault code 92 strangely now seems to have disappeared for some reason.

    92 Camshaft sensor Incorrect signal ==>not getting this now
    • mro
    • By mro 10th Jul 17, 12:59 PM
    • 595 Posts
    • 612 Thanks
    mro
    Saw something on Youtube about sensors like Air Mass Flow & Air Inlet Temperature, if they are faulty and you disconnect them, that can stop difficult starting, as ECU uses default settings.


    Tried disconnecting these 2 sensors one at a time, then both together, that didn't solve problem.
    • khcomp
    • By khcomp 10th Jul 17, 8:01 PM
    • 198 Posts
    • 82 Thanks
    khcomp
    Odd question: How long has the cambelt been on the car? If there's a problem with the belt's position or tension, its possible that the ECU will throw up camshaft & crankshaft sensor faults as they are not producing synchronised pulses...
    • mro
    • By mro 11th Jul 17, 12:19 AM
    • 595 Posts
    • 612 Thanks
    mro
    Odd question: How long has the cambelt been on the car? If there's a problem with the belt's position or tension, its possible that the ECU will throw up camshaft & crankshaft sensor faults as they are not producing synchronised pulses...
    Originally posted by khcomp
    Cam belt has just been changed, engine running lovely, nice, smooth & stable once it has started.

    It now seems pretty consistent, I keep cranking engine for say 10-15 seconds & it eventually starts.
    • Strider590
    • By Strider590 11th Jul 17, 7:08 AM
    • 11,285 Posts
    • 6,272 Thanks
    Strider590
    I assume you've done the obvious checks first? Spark plugs, leads, etc?

    ECU based diagnostics, even now can be hit n miss, but back in the mid 90's? I'd use a large pinch of salt.....
    Having the last word isn't the same as being right.......

    "Never confuse education with intelligence"
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