honda civic idle problem
- Thread starter mikexiong
- Start date
KSheets
New Member
Guys I'm new to the board here, but I've messed with Hondas for years. I've read numerous posts about checking/cleaning the IACV, bleeding air in cooling system, etc that MAY cure the surging idle problems many of us have/or have had. When all that fails as it did for my surging idle, I'll offer this suggestion. Today I just finished replacing the intake manifold gasket in my daughter's 99 Honda Civic EX, dy8/vtec and it FIXED the problem. Takes a bit of time but I'd be willing to bet it would help you guys out if you've tried all other "fixes" and it doesn't "fix" the idle issue. Mine was throwing a "P0505 Idle Air Control System" error code.
Sorry if this is common knowledge to you, but to test if this might be your problem, pull your air intake off at the throttle body/butterfly valve. Do not disconnect any connectors or sensors yet to avoid other false error codes. Place the palm of your hand over the opening (it's ok, it's safe) and if your engine sputters and dies this isn't your problem. Mine continued to run.... this shouldn't happen. If your car DOES continue to run after blocking the throttle valve opening, you have a fairly substantial vacuum leak.
Hondas are known for faulty or leaky Intake Manifold Gaskets and you'll never know it unless you do that test mentioned above. I even tried the carb cleaner spray test around the intake manifold and because my leak was on the underside, it didn't cause the engine to drag at all. The manifold gasket is about $4 but will take several hours of your time to dis-assemble and re-assemble. Mine took longer because I cleaned everything I could that was open to me with the intake manifold removed.
This repair will have you removing fuel lines/injectors and multiple cooling lines/vacuum lines, etc so label things and make sure the negative on your battery is disconnected to be safe (this will also clear your error code while you work). Sorry if any of this is redundant or has been posted elsewhere. I've searched many sights looking for fixes, but this is the only thing that really FIXED my error code and surging idle.
Best regards,
Klint
Sorry if this is common knowledge to you, but to test if this might be your problem, pull your air intake off at the throttle body/butterfly valve. Do not disconnect any connectors or sensors yet to avoid other false error codes. Place the palm of your hand over the opening (it's ok, it's safe) and if your engine sputters and dies this isn't your problem. Mine continued to run.... this shouldn't happen. If your car DOES continue to run after blocking the throttle valve opening, you have a fairly substantial vacuum leak.
Hondas are known for faulty or leaky Intake Manifold Gaskets and you'll never know it unless you do that test mentioned above. I even tried the carb cleaner spray test around the intake manifold and because my leak was on the underside, it didn't cause the engine to drag at all. The manifold gasket is about $4 but will take several hours of your time to dis-assemble and re-assemble. Mine took longer because I cleaned everything I could that was open to me with the intake manifold removed.
This repair will have you removing fuel lines/injectors and multiple cooling lines/vacuum lines, etc so label things and make sure the negative on your battery is disconnected to be safe (this will also clear your error code while you work). Sorry if any of this is redundant or has been posted elsewhere. I've searched many sights looking for fixes, but this is the only thing that really FIXED my error code and surging idle.
Best regards,
Klint