AP1 with 90k miles low compression
#1
AP1 with 90k miles low compression
I've had my AP1 for just about over a year and it had 69,000 miles when i got it. After driving it for approx 16,000 miles (85,000 on the odometer) the CEL comes on when i was very low on fuel. Went to pepboys to scan the codes and there were 3 codes: 301, 302 and 300.
So now, i try to figure out what caused the CEL to come on.
Step 1: changed the spark plugs with some ngks, deleted the codes then a few days later, CEL came back on.
Step 2: deleted code, switched coil pack #1 with #3 deleted the code again but it came back on a few miles later. Scanned it, now misfire on cylinder 1, 2 and 3. I thought it was the coil pack so i purchased 1 new coil pack and changed the one that i thought was faulty. As usual i deleted the code and guess what, it comes back on again. Now with a random misfire code. I switched the new coil pack to every single old one but the light kept on coming back.
Step 3: Compression Test. The numbers were:
Cyl #1: 130 PSI (dry) 190 PSI (wet)
Cyl #2: 100 PSI (dry) 130 PSI (wet)
Cyl #3: 220 PSI (dry)
Cyl #4: 200 PSI (dry)
The tests above were done at 90,000 miles.
Im a bit worried that i might have to rebuild/change the bottom end.
Any suggestions on what other options i have? Any other more conclusive tests that i should do? Thanks in advance for your response(s).
So now, i try to figure out what caused the CEL to come on.
Step 1: changed the spark plugs with some ngks, deleted the codes then a few days later, CEL came back on.
Step 2: deleted code, switched coil pack #1 with #3 deleted the code again but it came back on a few miles later. Scanned it, now misfire on cylinder 1, 2 and 3. I thought it was the coil pack so i purchased 1 new coil pack and changed the one that i thought was faulty. As usual i deleted the code and guess what, it comes back on again. Now with a random misfire code. I switched the new coil pack to every single old one but the light kept on coming back.
Step 3: Compression Test. The numbers were:
Cyl #1: 130 PSI (dry) 190 PSI (wet)
Cyl #2: 100 PSI (dry) 130 PSI (wet)
Cyl #3: 220 PSI (dry)
Cyl #4: 200 PSI (dry)
The tests above were done at 90,000 miles.
Im a bit worried that i might have to rebuild/change the bottom end.
Any suggestions on what other options i have? Any other more conclusive tests that i should do? Thanks in advance for your response(s).
#3
Moderator
Yes cylinder 1 and 2 are real bad.
Get someone whos knows engines to do a leakdown test. The right guy will tell you if you have scored walls, bent intake, or bent exhaust valves.
I think you have burned/bent valves in at least cylinder #2.
You're best bet right now is check your valve clearances. There is a moderate to fair chane you could cure it with a valve adjustment. If if you dont, you will have at least found your underlying issue that burned the valves (tight clearance) This is important, so as not to repeat history
Get someone whos knows engines to do a leakdown test. The right guy will tell you if you have scored walls, bent intake, or bent exhaust valves.
I think you have burned/bent valves in at least cylinder #2.
You're best bet right now is check your valve clearances. There is a moderate to fair chane you could cure it with a valve adjustment. If if you dont, you will have at least found your underlying issue that burned the valves (tight clearance) This is important, so as not to repeat history
#4
Billman250, are you saying that based on the "wet" test results there is still a chance that the problem that my engine's has is coming from the head?
Here are some facts that might help diagnosing the problem:
Oil consumption is at about 1/2 quart every 1200 miles
The car is bone stock and i've personally never tracked it.
It gets an average of 24mpg/28 hwy mpg.
I don't feel much of a powerloss and the engine is fairly quiet.
Vtec engages just fine.
Doesn't smoke at all.
It has a VERY slight(very few people notice it) misfire while idling
Here are some facts that might help diagnosing the problem:
Oil consumption is at about 1/2 quart every 1200 miles
The car is bone stock and i've personally never tracked it.
It gets an average of 24mpg/28 hwy mpg.
I don't feel much of a powerloss and the engine is fairly quiet.
Vtec engages just fine.
Doesn't smoke at all.
It has a VERY slight(very few people notice it) misfire while idling