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91 Civic LX low compression

Discussion in '4th Generation Honda Civic (1988-1991)' started by 91LXDriver, Dec 8, 2017.



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  1. 91LXDriver

    91LXDriver New Member

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    I have a 91 Civic LX with 187,000 miles on the original engine. I've discovered the poor performance is due to low compression in all 4 cylinders, 1-135, 2-141, 3-139, 4-143. I believe it's the rings. My question is can i, or is it possible, to replace the stock rings only or do I have to completely rebuild the engine?
     
  2. boofoo

    boofoo Respected Registered VIP

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    Nobody should draw the conclusion of low compression without you mentioning the precise conditions of the test.

    My first impression is that the compression numbers are fine.

    Please update your other threads.
     
  3. 91LXDriver

    91LXDriver New Member

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    Warm engine, spun 7-8 times, all plugs out. The numbers indicated represent an average with and without oil in each cylinder. The compression test with the oil was near normal, without the oil the tests for each cylinder were considerably lower. Also there is, in my opinion, excessive blow by in the block...
     
  4. boofoo

    boofoo Respected Registered VIP

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    No mention of test being done at WOT or disabling the fuel injectors.​

    Post the numbers with or without oil added separately for comparison of each cylinder.
     
  5. 91LXDriver

    91LXDriver New Member

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    Couldn't find my notes on first test so I reran test. I posted the previous info from memory. Fuel injectors disabled, without oil, #1-190, #2-185, #3-175, #4-185....with oil #1-195, #2-190, #3-180, #4-190....; so upon running the new test and comparing the numbers to the service manual these are near normal numbers. So now I'm perplexed as to the lack of performance, the only thing I have yet to replace is the catalytic converter.
     
  6. boofoo

    boofoo Respected Registered VIP

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    CEL codes?

    Last full ignition system tune up?

    Last time fuel filter replaced?
     
  7. 91LXDriver

    91LXDriver New Member

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    CEL codes???

    Plugs, wires 18 months ago, New distributor, cap, and rotor 2 years ago,
     
  8. boofoo

    boofoo Respected Registered VIP

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    Check engine light = CEL

    How many miles it 2 years?

    Ignition timing? Condition of plugs?

    Last time fuel filter replaced?

    More details about poor performance?
     
  9. 91LXDriver

    91LXDriver New Member

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    No cell codes......

    The only 2 things I can think k of is I still need to check fuel pressure and the alternator. The alternator light comes on upon starting the engine and at idle when headlamps are on.
     
  10. boofoo

    boofoo Respected Registered VIP

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    How do you know with certainty?

    Have you replaced the fuel filter?

    This is very informative. Measure voltage across the battery posts with the engine idling with or without the headlights on. Post the readings.
     
  11. 91LXDriver

    91LXDriver New Member

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    Ignition timing seems normal. Plugs have light brown to grey appearance. Miles put on in 2 yrs less than 10,0000.
    Fuel filter replaced about same time the other tune up matters done.

    Performance... when a accelerating from a stop it has very little pep to it takes a long time to get up to speed .
     
  12. 91LXDriver

    91LXDriver New Member

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    I will conduct this test and repost the readings
     
  13. 91LXDriver

    91LXDriver New Member

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    I do not have a OBD reader for this year of the car
     
  14. boofoo

    boofoo Respected Registered VIP

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    Have you actually checked with a timing gun?

    The problem is likely the ignition timing and/or the alternator.

    Remove the cat and inspect with a flashlight to see if the cat is clogged or melted.
     
  15. boofoo

    boofoo Respected Registered VIP

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    An OBD code reader would be useless for a 91 Civic. Does the CEL turn on while driving?
     
  16. 91LXDriver

    91LXDriver New Member

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    Timing has been checked with the timing gun and following the service manual instructions on how to check the timing. And because of previous fuel injector issues I routinely drive the car in a manner and able to see the ECU flashing lights if they appear . There is been no trouble codes since replacing the main relay and the fuel injectors a few months back . I'll check the alternator battery is you had described later and I'll have to pull the exhaust to get to the catalytic converter at a later time . I don't have time to conduct these other two testers I have to be at work in about an hour and 1/2 .
     
  17. civteck

    civteck Respected

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    Still would like to see fuel pressure at idle and under load.

    Sent from my boujea ass phone
     


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