Valve adjustment and misfires/low compression
08-26-2016, 07:31 PM
#22
The car has maybe 500 to 1000 miles since the first valve adjustment. I took the car to a third shop today and I'm pleased with the plan of action thus far. I will report to you all in the future regarding results once work is complete.
08-26-2016, 07:32 PM
#23
08-27-2016, 07:30 AM
#24
Having a history of failing emissions does raise and eyebrow. However if it ran good for 500-1000 miles before the first valve adjustment. Then after that the cel came within two weeks (200 miles??), there is a strong correlation betwween your issues and the work the first shop performed.
08-27-2016, 11:46 AM
#25
Having a history of failing emissions does raise and eyebrow. However if it ran good for 500-1000 miles before the first valve adjustment. Then after that the cel came within two weeks (200 miles??), there is a strong correlation betwween your issues and the work the first shop performed.
08-31-2016, 04:02 AM
#26
Registered User
I originally posted this on the Warning for DBW Cars thread because I am wondering if perhaps this is related to the problem Billman posted about.
I am re-posting it in perhaps a more visible thread, but with edits and an update, at the suggestion of cosmomiller. I'm looking for feedback from some knowledgeable folks as we work toward a solution (and hopefully soon; I miss my car). First is what happened. Then is where we're at in our heads after some back-and-forth with a very knowledgeable good friend and some thinking and talking.
We have a stock '06 with 65K on it. Owned 14 mos., no issues so far. Until last week, when the check engine light came on, went off, came on again. Took it to Honda dealer where I've had all my Hondas serviced for 15 years. Computer diagnostic showed codes for #2 misfire. Since swapping coils and plugs, didn't fix, they did a leak-down test and found 65-75% leakage on #2. Valve adjustment revealed that "valves are inspec at this time." Honda TechLine told the shop techs that the head needed to be replaced for valve damage. "Tech found that the stored history shows that the damage occurred after the car was running 55 seconds at an operating temperature of 172 degrees. Tech found that the RPMs were at 3951 at 18 mph causing damaage to the valves on cylinder #2."
In conversation, the service adviser said it was a bent (or burnt--might have misunderstood him--David thinks burnt) valve, but they didn't get that specific in the summary. The consensus of the shop foreman, technician, and service adviser was that over-revving just after start-up or a missed shift did it.
Both cosmomiller and my experienced sports-car friend David said they see no way this engine damage could be related to driving 18 mph at 4K rpm no matter how cold the car was or how long that went on; that it's coincidental. That makes sense to me. Looks most likely that there was some valve-related problem lurking in there that just made itself known when that CEL came on. The consensus so far, small though it may be, is that next step needs to be getting the head off and the valves thoroughly inspected by a competent shop, and that replacing the head with a factory head at $6,050 is definitely not called-for. David said:
"Taking off the head is typical grease monkey stuff that can be done by many. The forums probably know who has the best machine shop and you can just sent it UPS.
Putting it back together is higher level work. Not genius but competent. Need to torque the bolts down gradually and in a particular order. Need to get the timing ...chain...right or you will have 16 ...bent valves...if screwed up...but you'll find the right person for assembly and machining and none of that bad stuff will happen.
I would not put a brand new factory head on the car if just one is messed up.
The machine shop should probably check everything, lap the seats, replace the retainers because you're there and those can [have unwanted sex with] you if they break from fatigue. That's about it."
I think at this point the most important thing is to find the right shop to work on the head. I am in Wilmington, NC. If I can't get a solid enough rec for someone local, I guess we will have to look into flatbedding the car to Raleigh or somewhere. Would love to avoid that cost if possible but not worth risking a less-than-perfect repair.
Thanks,
Phillip
I am re-posting it in perhaps a more visible thread, but with edits and an update, at the suggestion of cosmomiller. I'm looking for feedback from some knowledgeable folks as we work toward a solution (and hopefully soon; I miss my car). First is what happened. Then is where we're at in our heads after some back-and-forth with a very knowledgeable good friend and some thinking and talking.
We have a stock '06 with 65K on it. Owned 14 mos., no issues so far. Until last week, when the check engine light came on, went off, came on again. Took it to Honda dealer where I've had all my Hondas serviced for 15 years. Computer diagnostic showed codes for #2 misfire. Since swapping coils and plugs, didn't fix, they did a leak-down test and found 65-75% leakage on #2. Valve adjustment revealed that "valves are inspec at this time." Honda TechLine told the shop techs that the head needed to be replaced for valve damage. "Tech found that the stored history shows that the damage occurred after the car was running 55 seconds at an operating temperature of 172 degrees. Tech found that the RPMs were at 3951 at 18 mph causing damaage to the valves on cylinder #2."
In conversation, the service adviser said it was a bent (or burnt--might have misunderstood him--David thinks burnt) valve, but they didn't get that specific in the summary. The consensus of the shop foreman, technician, and service adviser was that over-revving just after start-up or a missed shift did it.
Both cosmomiller and my experienced sports-car friend David said they see no way this engine damage could be related to driving 18 mph at 4K rpm no matter how cold the car was or how long that went on; that it's coincidental. That makes sense to me. Looks most likely that there was some valve-related problem lurking in there that just made itself known when that CEL came on. The consensus so far, small though it may be, is that next step needs to be getting the head off and the valves thoroughly inspected by a competent shop, and that replacing the head with a factory head at $6,050 is definitely not called-for. David said:
"Taking off the head is typical grease monkey stuff that can be done by many. The forums probably know who has the best machine shop and you can just sent it UPS.
Putting it back together is higher level work. Not genius but competent. Need to torque the bolts down gradually and in a particular order. Need to get the timing ...chain...right or you will have 16 ...bent valves...if screwed up...but you'll find the right person for assembly and machining and none of that bad stuff will happen.
I would not put a brand new factory head on the car if just one is messed up.
The machine shop should probably check everything, lap the seats, replace the retainers because you're there and those can [have unwanted sex with] you if they break from fatigue. That's about it."
I think at this point the most important thing is to find the right shop to work on the head. I am in Wilmington, NC. If I can't get a solid enough rec for someone local, I guess we will have to look into flatbedding the car to Raleigh or somewhere. Would love to avoid that cost if possible but not worth risking a less-than-perfect repair.
Thanks,
Phillip
08-31-2016, 04:40 AM
#27
Is the engine apart, already? If not... I'd do another leakdown test & find out for sure, where the leak is occurring. Exhaust valves, intake valves, compression rings, etc.
My guess is, being a DBW S2000 --- the exhaust valves got burnt after being too tight lash, for too long time.
Good luck with fix!
My guess is, being a DBW S2000 --- the exhaust valves got burnt after being too tight lash, for too long time.
Good luck with fix!
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