91 Civic LX low compression

91LXDriver

New Member
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?
 

91LXDriver

New Member
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...
 


91LXDriver

New Member
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.
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.
 

91LXDriver

New Member
CEL codes???

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


91LXDriver

New Member
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.
 

91LXDriver

New Member
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?
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 .
 

91LXDriver

New Member
How do you know with certainty?

The ECU light there are no flashing codes

Have you replaced the fuel filter?
same time I did the other tuneup issues


This is very informative. Measure voltage across the battery posts with the engine idling with or without the headlights on. Post the readings.
I will conduct this test and repost the readings
 

91LXDriver

New Member
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 .
 

civteck

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

Sent from my boujea ass phone
 

91LXDriver

New Member
Checked the converter could see very little light pass through, it was rattling too, replaced it, a little better performance. Next to check alternator and recheck timing....
 

91LXDriver

New Member
Checked voltage per book instructions....at idle volts are 13.95 but go up to 14.10. With lights on voltage drops to 13.65 fluctuates a few tenths but never goes up over 14. With higbeams on it drops further 13.33....

Checked timing following the book, it looks like it's about 5 degrees further than it should be, I adjusted distributor as far as it could go...
 

91LXDriver

New Member
Replaced alternator, there was some noticeable improvement but not what I was expecting. Still sluggish from a stop. Next I'll check fuel pressure, I guess. I'm getting frustrated with this...
 

91LXDriver

New Member
Checked timing following the book, it looks like it's about 5 degrees further than it should be, I adjusted distributor as far as it could go to get it within 5 degrees, the only other thing I can think of is to pull the timing belt cover and check the timing marks there to see if it's correct....
 

MotorMo

Respected
In recent years I have seem several OBD 0 Civics with issues of ignition timing being off due to after market distributors being installed. They literally don't rotate as far as needed to get it with in spec. And confirmed that the TD# stamp was correct on the casing. Hard to find original distributor for these generations...
- But if your mechanical timing was off, the ignition timing would also be out, so check the basics- mechanical timing is critical. Good luck.
 

91LXDriver

New Member
In recent years I have seem several OBD 0 Civics with issues of ignition timing being off due to after market distributors being installed. They literally don't rotate as far as needed to get it with in spec. And confirmed that the TD# stamp was correct on the casing. Hard to find original distributor for these generations...
- But if your mechanical timing was off, the ignition timing would also be out, so check the basics- mechanical timing is critical. Good luck.
The original distributor self detonated almost 3 years ago, the replacement was from O'Reilly auto parts. This happened 6 months after the timing belt ripped to shreds on the highway at 70mph. So no the distributor is a replacement for the original.....
 


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