WHAT IS THE PROBLEM OF ISUZU 4HL12 WHEN THE RPM ...

  • Tiny
  • vmandap
  • 2000 Isuzu Elf

What is the problem of isuzu 4HL1-2 when the RPM goes down to 1000 RPM the engine will shut off, I already check the module or computer box but its fine, also the injector is okey checked by the calibiration and they are set at 800 RPM, fuel line are good also the fuel presure is fine, and the electrician already check the wiring and everything is okey but the engine still turning off when RPM goes down to 1000, Can somebody help me to this Engine Trouble?
i just replace the piston without pulling down the engine recondiyion the cylinder head after, the engine start the trouble just come out, I've already Break-in the engine for three week at1500 RPM but when I bring it down to 800or lower to it 1000, the engine will automatically turn off, if there is anybody encounter tjis kind of engine trouble please share me the sollution.

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Saturday, January 5th, 2013 AT 8:11 AM

8 Replies

  • Tiny
  • KHLow2008
  • Expert
  • 41,997 posts

Check the valve clearances. Have the compression tested.

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Saturday, January 5th, 2013 AT 7:54 PM
  • Tiny
  • vmandap
  • Member

Already checked, the piston is newly replace with new one, and piston ring. Valve clearance also okey, the compresion test 420 PSI

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Sunday, January 6th, 2013 AT 12:32 AM
  • Tiny
  • KHLow2008
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Did you check for trouble codes?
Were the timing for camshaft installed correctly?

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Sunday, January 6th, 2013 AT 7:29 AM
  • Tiny
  • vmandap
  • Member

Yes, I checked trouble codes and timing of camshaft correctly installed still the same problem, I pull out the wiring of camshaft sensor, and the engine run normal, will it be possible if I will not replace the camshaft sensor and leave it unconnected to the wiring will not cause any trouble to the system?

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Tuesday, January 8th, 2013 AT 11:21 PM
  • Tiny
  • KHLow2008
  • Expert
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Something is wrong with the cam sensor and when it is disconnected, the engine computer would make compensation for it to run.

For petrol engine a fault with the camsensor would normally result in non starting as the fuel injectors would not be working. As to diesel engines, I am not sure as to the reaction from the engine computer when the cam sensor is disconnected for long periods.

You would have to test the sensor and the pick up point at cam to see if there are any damages. If everything is good, I would point to the camsensor or camshaft timing.

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Wednesday, January 9th, 2013 AT 1:28 PM
  • Tiny
  • vmandap
  • Member

Ive already change the camshaft sensor with a good one but when I connected the wiring it appears again with the same problem the engine shut down at 1000 RPM or lower than 1000RPM but over 1000RPM its okey.

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Friday, January 11th, 2013 AT 11:31 PM
  • Tiny
  • KHLow2008
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  • 41,997 posts

Try another computer to see if it works.

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Wednesday, January 23rd, 2013 AT 2:16 PM
  • Tiny
  • reyose19
  • Member

Doesyour engine is ok now? I know

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Sunday, March 22nd, 2015 AT 4:18 AM

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