Care to Diagnose this engine with dead cylinder? 1988 Civic DX - D15B6 engine
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Joined: Mar 2004
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From: Dundas, ON, Canada
Care to Diagnose this engine with dead cylinder? 1988 Civic DX - D15B6 engine
Hello, thought I would give this board a try re. my girlfriend's 1.5L SOHC 16 valve civic.
Here is some info:
Car has always used lots of oil (external leaks as well as into the #1 cylinder) but ran well. Suddenly it runs very rough and with low power, and I suspected a badly oil fouled #1 plug as the reason. I was surprised by these results.
Compression test (185 psi is spec minimum)
Cyl 1 185 psi (oily plug)
Cyl 2 165 psi (whitish plug)
Cyl 3 0 psi (oily plug)
Cyl 4 185 psi (slight oily plug)
At idle, intake manifold vacuum fluctuates between 14 - 18 inHg (20 is normal) in rhythm with the engine, I assume during the #3 cylinder intake stroke. It levels out and increases to 20 at higher rpm.
I will be getting the gauge to do a cylinder leakdown test next week.
So far I am assuming one of the #3 intake valves is stuck open or broken.
QUESTION:
Could a bad intake valve cause both 0 compression and oil leakage into the cylinder, or is the piston ring likely shot as well?
Any other guesses at the diagnosis?
I have not done a valve adjustment / repair before but am a pretty good auto do-it-yourselfer. Any estimates on how long I should expect this repair to take?
Thanks for any comments.
Here is some info:
Car has always used lots of oil (external leaks as well as into the #1 cylinder) but ran well. Suddenly it runs very rough and with low power, and I suspected a badly oil fouled #1 plug as the reason. I was surprised by these results.
Compression test (185 psi is spec minimum)
Cyl 1 185 psi (oily plug)
Cyl 2 165 psi (whitish plug)
Cyl 3 0 psi (oily plug)
Cyl 4 185 psi (slight oily plug)
At idle, intake manifold vacuum fluctuates between 14 - 18 inHg (20 is normal) in rhythm with the engine, I assume during the #3 cylinder intake stroke. It levels out and increases to 20 at higher rpm.
I will be getting the gauge to do a cylinder leakdown test next week.
So far I am assuming one of the #3 intake valves is stuck open or broken.
QUESTION:
Could a bad intake valve cause both 0 compression and oil leakage into the cylinder, or is the piston ring likely shot as well?
Any other guesses at the diagnosis?
I have not done a valve adjustment / repair before but am a pretty good auto do-it-yourselfer. Any estimates on how long I should expect this repair to take?
Thanks for any comments.
Joined: Nov 2003
Posts: 1,060
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From: Colorado, USA
Re: Care to Diagnose this engine with dead cylinder? 1988 Civic DX - D15B6 engine (allanwayne)
Sorry, I don't know what will solve your problem besides a nice motor swap. I am sure others will follow me in here and actually diagnose this problem.
Good luck brotha.
Good luck brotha.
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Joined: May 2002
Posts: 9,814
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From: Granada Hills, Ca, USA
Re: Care to Diagnose this engine with dead cylinder? 1988 Civic DX - D15B6 engine (allanwayne)
You might as well skip the leak down test. If you have a 0 reading then either you have a broken vavle or a broken piston. It's going to be very obvious when you open the motor up. I say just take the head off and see what it is and use that money you saved by not buying the leak down tester toward repairs.
If it were readling low like90 or something then I would suggest the leakdown to find out if it were severe blowby on the rings or some bad valve seals or such. Reading 0 means that nothing is going on in the cylinder. You might as well not even ahve a piston in there.
PS - did you check the compression by first pulling out ALL the spark plugs and disconnection the fuel supply?
If it were readling low like90 or something then I would suggest the leakdown to find out if it were severe blowby on the rings or some bad valve seals or such. Reading 0 means that nothing is going on in the cylinder. You might as well not even ahve a piston in there.
PS - did you check the compression by first pulling out ALL the spark plugs and disconnection the fuel supply?
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