Finally found p0505 solution

[mcnabb_nfl]

For the past 6 months I've been having the p0505 issue where the car would jerk/bounce rpms around 1700 and idle high/hunting. After posting to many sites and troubleshooting, and checking for vac leaks, replacing iacv, adjusting idle etc with nothing working, I finally found the issue. CHECK YOUR AIR ASSIST SOLENOID! If I
Am correct it is designed to allow more air into the engine when cold to help allow the car to reach temp, and when the car reaches roughly 150 degrees it's suppose to shut itself. After testing, mine was staying open all the time! I hope this may be of some help, if you've checked everything else dont forget to check this! My car has been like new ever since. Car is a 1999 civic ex manual.

 

[danielhawkins86]

You have just answered a question I have posted everywhere. Thanks. Where abouts was this located on the car?

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[mcnabb_nfl]

You have just answered a question I have posted everywhere. Thanks. Where abouts was this located on the car?

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On one of the coolant feed lines on the rear of the motor, is where the air assist solenoid sits. Near the vtec solenoid, but lower. It has 2 hoses, one from the intake hosing, the other to intake manifold right at the block.

 

[Francisco Colin]

For what engine is this cause I have the same problem on my b16a2 but cannot seem to locate this part.
Thank you

 

[mcnabb_nfl]

It's a stock d16y8. I'm not sure if your engine has one or not...I don't think so though!

For what engine is this cause I have the same problem on my b16a2 but cannot seem to locate this part.
Thank you

 

[Francisco Colin]

I was wondering what engine cause I was looking for that part on my b16 and could not find it.
Thank You

 

[GiMiK]

On one of the coolant feed lines on the rear of the motor, is where the air assist solenoid sits. Near the vtec solenoid, but lower. It has 2 hoses, one from the intake hosing, the other to intake manifold right at the block.

I've been battling this issue for quite some times now. I replaced the IAC valve, cleaned it again still have the code keeps popping. By the way, would you think this will have same location on non VTEC motor?

Thank you in advance.

 

[GiMiK]

What car and engine do you have?

1999 CIVIC LX Sedan stock motor D16Y7, I assumed. I'm not home right now, and I was just searching it.

 

[GiMiK]

You posted in a thread for owners of the 99-00 Civic EX not the 99-00 Civic LX.

Describe the nature of your idle problem.

When the light is on, feels like the its hesitating to shift to next gear. When Cruise Control is set, transmission keeps shifting up and down to maintain the set speed. If the light is not on (reset) car runs normal, shifting smooth, keeps the set speed when cruise control is set. Every time I got the code read, keeps coming up with P0505.

IAC valve been replaced, and re-cleaned, electrical plug has been cleaned and checked. Vacuum has been checked, and no leaks was found.

 

[GiMiK]

Describe the idle problem when the code is thrown.

Also test the TPS.

Idle is higher RPM and it jumps around, between 1.5 to 2.

TPS has not been tested or checked, I will check it this weekend.