Redprelude98

so i have recently changed my iacv and put a new one on it and i am still throwing this code and i dont know what else it really involves changing or replacing or whatever. Is there anyone who knows what my problem could be because my idle is acting wierd but it is not bouncing everywhere it just drops real low when i put it in neutral to come to a stop and sometimes it drops so low that it dies. Could this mean i need to replace my tps sensor or some other sensor? oh yeah it is a 97 civic ex d16y8

Linked

https://honda-tech.com/forums/tech-misc-15/heres-list-obd2-codes-if-anyone-cares-466877/

sticky's your friend

P0505 Idle Control System Malfunction

goodluck

Former User

Does the idle speed drop or the engine stall when you unplug the IACV connector? If not, the IACV is bad. If so, try to adjust the idle speed with the idle screw on the throttle body and also check whether the throttle body port leading to the IACV is clogged

In some rare cases, a bad TPS or ECT sensor can also throw P0505, so check the other items first.

Redprelude98

yes it does drop real low and i have cleaned the throttle body real good like 3 weeks ago. what if my idle is right at 800 when i am stopped though and it just drops while i am driving and put it in neutral

Redprelude98

yeah i already knew it was my idle control system i was just asking what else could it be like what is the actual problem...you know what i mean but thanks that is a good page to have...lol

Former User

Try adjusting the idle screw on the top of the throttle body. If you don't get any satisfaction there, try bleeding the cooling system. The last step would be to electrical troubleshoot the TPS and ECT sensors.

Redprelude98

i have already bled the coolant system and flushed it and what should i adjust the idle screw to?

Linked

ohhh my mistake then lol

well on the subject, i have a similar problem (some ways)

in RARE times when i start my car. i will start it and the engine would fast idle (1.5-2k idling to warm up engine). sometimes when it does that, the engine stalls and i would have to start it again then everything is fine.

it does it also when the engine is warmed up (at about 800rpms)

it stalls rarely and doesnt have any pattern to it really.

i have an automatic tranny BUT i could also suspect my fuel pump going out. i use to run it on almost empty constantly for the last 10k miles lol, but i do prime it 100% everytime i start my car

Redprelude98

well i just replace my fuel pump as well thinking that could be my problem...lol

Former User

The procedure below requires an accurate tach or a scan tool:

Redprelude98

well i have a apexi neo and it shows the rpms on there do you think that would work

Redprelude98

thank you when i get off of work i will try that and let you know how things work out for me

Former User

Not sure. Maybe someone else can tell you whether it is accurate enough. I know the stock dash tach is not.

Redprelude98

Yeah i know because my stock dash tach is off from my apexi neo

waaBAAH

did you reset your ECU after the IAC install?

Redprelude98

you mean just plug the obd2 reader and clear the codes...if you mean that then yes but if not then probably not

waaBAAH

yeah..clearing of the codes.. if you did clear them then good..

carry on guys.. lol

Redprelude98

thank you but yeah i did clear them i just wish i could fix the problem and it be easy, but with me it never is and it is never cheap either

Former User

Look on the bright side. At least you have a CEL code to somewhat focus your troubleshooting.

waaBAAH

1997 Honda Civic EX 1.6L

Customer Concern: The idle is surging up and down when the transmission is in Park or Neutral. Code P0505 is setting.

Tests/Procedures:

1. Remove the air cleaner assembly and find the bypass port that feeds air to the Idle Air Control (IAC) valve and block it with a finger when the vehicle is running. The idle should slow down and stop surging.

2. Cover the throttle body and verify that the engine stalls. If the engine stalls, there are no vacuum leaks.

With a scan tool or a volt meter, test the power steering pressure switch. Verify the status on the scan tool will change when the wheels are turned all the way. If using a volt meter verify the voltage on the Green wire is grounded but the power steering pressure switch until the wheel are turned all the way. If the power steering pressure switch is faulty and indicates the steering wheel is turned all the way then the Engine Control Module (ECM) will idle up the vehicle and because there is not load from the power steering the idle can surge up and down.

3. Locate the IAC valve 3-wire connector. With the vehicle running, back probe and ground the Orange (ORN) wire and the idle should decrease. If the idle does not decrease or slow way down, remove the IAC valve and see if it is sticking.

Potential Causes:

Leaking Engine Vacuum
Idle Air Control (IAC) Valve
Power Steering Pressure Switch (PSPS)

Tech Tips: On the Idle Air Control (IAC) valve, the Orange (ORN) wire grounds the closed windings and the Black/Blue (BLK/BLU) wire grounds the open windings.

Diagnostic Codes: P0505

Author: Wayne Pasicznyk

waaBAAH

i understand you dont have a fluctating idle but test one and three both talk about low idle so maybe the port to the iac is plugged.

maybe orange wire is grounded for some reason resulting in low idle.