Idle Control System Troubleshooting - Next Steps
01-17-2016
#31
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Re: Idle Control System Troubleshooting - Next Steps
Well, back to this classic misfiring problem. Same car, ~ 12 months / 15k miles later following a mechanic job where the following were replaced/repaired: 3 bent/bad valves, head gasket, water pump, timing belt, intake manifold (used, but correct part). Beforehand, I replaced the: spark plugs, plug wires, distributor rotor, and ignition coil.
About 3 weeks ago, I got some random misfire codes and the CEL blinked a few times while misfiring. Unsure what to do, I ran two bottles of injector cleaner through the car and it seemed to go away. Yesterday, it started again. I decided I would do a dry compression test to try and eliminate the valves as the problem. The results:
Cylinder 1 ~ 90 psi
Cylinder 2 < 30 psi
Cylinder 3 ~ 115 psi
Cylinder 4 ~ 90 psi
I am not sure how this can possibly be in only one year since the valve job. Anyhow, I decided to check the plugs for fouling, and I found:
https://i.imgur.com/1pUWsZN.jpg
Pretty nasty for such a short time. These were NGK plugs that the mechanic used. I went ahead and swapped in new NGK Iridiums. The car still idles poorly (low, and shuddering). It doesn't seem to have helped. Still, I guess my next step should be to check the plug wire resistances and ignition coil voltage (resistance?). Any thoughts?
Forgot to add: the error codes were
P0300 Random misfire
P0301 Cylinder 1 misfire
P0302 Cylinder 2 misfire
P1399 Random misfire
About 3 weeks ago, I got some random misfire codes and the CEL blinked a few times while misfiring. Unsure what to do, I ran two bottles of injector cleaner through the car and it seemed to go away. Yesterday, it started again. I decided I would do a dry compression test to try and eliminate the valves as the problem. The results:
Cylinder 1 ~ 90 psi
Cylinder 2 < 30 psi
Cylinder 3 ~ 115 psi
Cylinder 4 ~ 90 psi
I am not sure how this can possibly be in only one year since the valve job. Anyhow, I decided to check the plugs for fouling, and I found:
https://i.imgur.com/1pUWsZN.jpg
Pretty nasty for such a short time. These were NGK plugs that the mechanic used. I went ahead and swapped in new NGK Iridiums. The car still idles poorly (low, and shuddering). It doesn't seem to have helped. Still, I guess my next step should be to check the plug wire resistances and ignition coil voltage (resistance?). Any thoughts?
Forgot to add: the error codes were
P0300 Random misfire
P0301 Cylinder 1 misfire
P0302 Cylinder 2 misfire
P1399 Random misfire
01-17-2016
#32
If you think a good mechanic is expensive, try hiring a bad one
Re: Idle Control System Troubleshooting - Next Steps
Low compression numbers...
#2 plug looks like that cylinder is about dead.
and oil burning is the hard crusty buildup on all the plugs. (Looks like you should use the cheap plain NGK V-Power instead of precious metal plugs)
Ring job for the oil burning.
Low compression, you probably need to do a cylinder leakage test to figure out what's leaking, where the compression loss is going ----you say it's valves, this should prove it.
Then compare which cylinders are leaking from which valves, and see if it's the same valves as last time.
Was a complete valve job done (replace 3 bent ones and grind/lap the others) last time, or was it just replacing the bent ones only?
A poorly done valve job has the potential for only lasting a short time.
#2 plug looks like that cylinder is about dead.
and oil burning is the hard crusty buildup on all the plugs. (Looks like you should use the cheap plain NGK V-Power instead of precious metal plugs)
Ring job for the oil burning.
Low compression, you probably need to do a cylinder leakage test to figure out what's leaking, where the compression loss is going ----you say it's valves, this should prove it.
Then compare which cylinders are leaking from which valves, and see if it's the same valves as last time.
Was a complete valve job done (replace 3 bent ones and grind/lap the others) last time, or was it just replacing the bent ones only?
A poorly done valve job has the potential for only lasting a short time.
01-18-2016
#33
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Low compression numbers...
#2 plug looks like that cylinder is about dead.
and oil burning is the hard crusty buildup on all the plugs. (Looks like you should use the cheap plain NGK V-Power instead of precious metal plugs)
Ring job for the oil burning.
Low compression, you probably need to do a cylinder leakage test to figure out what's leaking, where the compression loss is going ----you say it's valves, this should prove it.
Then compare which cylinders are leaking from which valves, and see if it's the same valves as last time.
Was a complete valve job done (replace 3 bent ones and grind/lap the others) last time, or was it just replacing the bent ones only?
A poorly done valve job has the potential for only lasting a short time.
#2 plug looks like that cylinder is about dead.
and oil burning is the hard crusty buildup on all the plugs. (Looks like you should use the cheap plain NGK V-Power instead of precious metal plugs)
Ring job for the oil burning.
Low compression, you probably need to do a cylinder leakage test to figure out what's leaking, where the compression loss is going ----you say it's valves, this should prove it.
Then compare which cylinders are leaking from which valves, and see if it's the same valves as last time.
Was a complete valve job done (replace 3 bent ones and grind/lap the others) last time, or was it just replacing the bent ones only?
A poorly done valve job has the potential for only lasting a short time.
I do not think the head gasket is blown as it is not smoking as far as I can tell. The car has used oil for years though. Maybe not "burned" - never seen blue smoke. And not slung either as far as I can tell. Just... "used" - don't know how else to describe it...
Yes, I believe it was a full valve job with grinding the non replaced valves last time.
Last edited by civNC00; 01-18-2016 at 05:24 AM.
01-18-2016
#34
If you think a good mechanic is expensive, try hiring a bad one
Re: Idle Control System Troubleshooting - Next Steps
I do not think the head gasket is blown as it is not smoking as far as I can tell. The car has used oil for years though. Maybe not "burned" - never seen blue smoke. And not slung either as far as I can tell. Just... "used" - don't know how else to describe it...
Oil loss without leaking externally is considered consumption.
Any oil that is consumed inside the engine goes through the combustion chamber, and evidence is normally left on the spark plugs. (If it's losing oil through the exhaust valve stem seals, that would not show on the plugs, but that's not a typical issue.)
A hot catalytic converter can hide a lot of oil smoke.
And it's hard to see what isn't in front of you --smoke would be behind you and unless it's a huge cloud most would not notice in the rear view mirrors.
01-18-2016
#35
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Used is an option, but I would spend a bit to freshen it up AND you don't know if it is going to be an oil user either.
I did not suspect the head gasket at all.
Oil loss without leaking externally is considered consumption.
Any oil that is consumed inside the engine goes through the combustion chamber, and evidence is normally left on the spark plugs. (If it's losing oil through the exhaust valve stem seals, that would not show on the plugs, but that's not a typical issue.)
A hot catalytic converter can hide a lot of oil smoke.
And it's hard to see what isn't in front of you --smoke would be behind you and unless it's a huge cloud most would not notice in the rear view mirrors.
I did not suspect the head gasket at all.
Oil loss without leaking externally is considered consumption.
Any oil that is consumed inside the engine goes through the combustion chamber, and evidence is normally left on the spark plugs. (If it's losing oil through the exhaust valve stem seals, that would not show on the plugs, but that's not a typical issue.)
A hot catalytic converter can hide a lot of oil smoke.
And it's hard to see what isn't in front of you --smoke would be behind you and unless it's a huge cloud most would not notice in the rear view mirrors.
01-18-2016
#36
If you think a good mechanic is expensive, try hiring a bad one
Re: Idle Control System Troubleshooting - Next Steps
01-18-2016
#37
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I do have the 1996 - 2000 Honda Civic service manual.
01-18-2016
#38
If you think a good mechanic is expensive, try hiring a bad one
Re: Idle Control System Troubleshooting - Next Steps
. I'd be inclined to believe valves were not the problem. I don't know yet w/o the leakdown test or some other test. If valves are not the problem, would a short block be a good option?
Did you check valve clearances yet?
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