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Honda D16Y8 Idle Screw Removal


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NaymzJaymz
User

Jun 18, 2023, 8:19 AM

Post #1 of 7 (1017 views)
Honda D16Y8 Idle Screw Removal Sign In

2000 Honda Civic
D16Y8 Engine @266K
5 Speed MT

I'm attempting to remove the idle screw from this engine. I've had the worst time with the idle issues on this vehicle, and I thought it would be worth checking(even if it's just for cleaning), although I don't know if it's the issue, of course. My problem is when I back the screw out and get to the end of the "adjustment range" the screw stops moving, as if it's not meant to be removed. Someone told me to lube the screw, and it will come out. This didn't help me, and I'm worried I'm going to damage the aluminum throttle body. I notice that the OEM parts suppliers sell this screw with an o-ring, so shouldn't it be removable? The throttle body is still on the engine.

Thank you again for the help I have received on this forum over the years. I don't mean to sound naive in my questions. I'm just trying to save a few bucks, and keep my old car on the road a while longer between 70 hour work weeks.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jun 18, 2023, 8:46 AM

Post #2 of 7 (1013 views)
Re: Honda D16Y8 Idle Screw Removal Sign In

Why are you messing with that screw at all.

The idle speed is NOT ADJUSTABLE on this vehicle. The computer and IAC have full control of idle speed.

That screw is for setting the idle stop for the IAC to take over from there. That could be a good reason you are getting the P0505.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on Jun 18, 2023, 8:47 AM)


NaymzJaymz
User

Jun 18, 2023, 11:41 AM

Post #3 of 7 (986 views)
Re: Honda D16Y8 Idle Screw Removal Sign In

Hammer,
I really didn't know that I shouldn't try an idle screw adjustment. There are all kinds of internet forum posts with guys doing this, but they are probably guys like me trying to figure things out. I'm not contradicting you, just trying to answer your "why are you messing with it" question.

Out of respect for forum rules, I wasn't going to mention the P505 code because I already did a post about that. To rehash a bit, I smoke tested everything extensively and have not found a hint of a vacuum leak from the throttle body onward through the engine. I replaced the IAC with a used OEM unit with no improvement. A new one (OEM) is very expensive, so I meant well that way. I've also purged the coolant. I'm worried that purchasing a new OEM IACV won't cure the issue, and I'll be stuck a car with a new IAVC that cost about half what the whole car is worth. In your opinion, is P505 caused only by the IACV itself having an issue? It all started long before I ever touched that idle screw.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jun 18, 2023, 11:47 AM

Post #4 of 7 (983 views)
Re: Honda D16Y8 Idle Screw Removal Sign In

No, like I just said the code is likely because you messed with the idle bleed screw and now the IAC has no baseline.

Here is some text from a TSB on the subject.

03-016

May 19, 2006

Applies To:
1998-02 Accord -ALL
1996-00 Civic -ALL
1997-01 CR-V - ALL
1997-01 Prelude - ALL
*1999-04 Odyssey - ALL*

Inspecting Idle Speed With the PGM Tester or Honda Diagnostic System

(Supersedes 03-016, dated March 25, 2003, to update the information marked by asterisks)

BACKGROUND

The ECM/PCM controls the vehicle's idle speed with the idle air control (IAC) valve. The IAC valve and the air bleed screw (idle adjusting screw) work together to allow the proper amount of air into the intake manifold when the throttle valve is closed (the accelerator pedal is released).

The ECM/PCM "learns" to work the IAC valve based on the total amount of air entering the intake manifold. Air can enter the intake manifold from several sources, including the air bleed screw, but only the air bleed screw is adjustable. If any changes are made that alter this airflow, specifically with the air bleed screw, the ECM/PCM must learn new idle parameters.

When the air bleed screw is properly set, the ECM/PCM controls the engine's idle speed seamlessly. But when the air bleed screw is not properly set, either of these symptoms may be present:

^ Idle speed dips and then quickly recovers.

^ Engine stalls intermittently when it is just "off-idle." Here are the criteria for this symptom:

- The accelerator pedal is released but the driver's right foot rests over the pedal, causing just enough pressure for the ECM/PCM to detect an input, yet there is little or no throttle valve opening (the throttle valve is either not allowing any airflow or it is opened so slightly that more air supply is needed).

- The engine speed is about 1,250 rpm or less.

- The lockup clutch (A/T models) or the clutch (M/T models) is disengaged.

- All during this time, the driver's foot does not move and stays resting over the accelerator pedal.

- The air bleed screw is not set properly and does not allow enough airflow.

- The amount of "air leakage" into the intake manifold is very low. (The normal amount of air let into the intake manifold by sources other than the IAC valve, the air bleed screw, and normal operation of the throttle body can vary slightly from vehicle to vehicle.)

NOTE:
"Air leakage" cannot be easily checked. If the first four criteria are met when the vehicle stalls, you can assume the last two criteria are met as well.

CORRECTIVE ACTION

L4 Models and 1999-00 Odyssey: Inspect the idle speed with the PGM Tester or Honda Diagnostic System (HDS) (see INSPECTION PROCEDURE A).

V6 Models except 1999-00 Odyssey: Inspect the idle speed with the PGM Tester or HDS, and clean out the throttle body if needed (see INSPECTION PROCEDURE B).

PARTS INFORMATION

Throttle Body Gasket (use only if needed): Refer to the parts catalog.

TOOL INFORMATION

PGM Tester with SN 320

or

Honda Diagnostic System with 1.006.004 or later software

REQUIRED MATERIALS

Carburetor Cleaner:

P/N 08732-0006, H/C 4713673

or

Throttle Plate and Induction Cleaner:

P/N 08732-9009, H/C 6204945

WARRANTY CLAIM INFORMATION

In warranty:
The normal warranty applies.

Inspect Idle Speed (L4 and V6 Models)

Operation Number: 120301 Flat Rate Time: 0.6 hour Failed Part: P/N 16400-PAA-A61 H/C 5429006 *Defect Code: 07403 Symptom Code: 08901* Skill Level: Repair Technician

Clean Throttle Body (V6 Models Except 1999-00 Odyssey) Operation Number: 216001 Flat Rate Time: 0.6 hour Failed Part: P/N 16400-PAA-A61 H/C 5429006 *Defect Code: 08103 Symptom Code: 08901* Skill Level: Repair Technician

NOTE:
Warranty claims for these labor operations must be submitted separately. Do not combine them on the same claim.

Out of warranty:
Any repair performed after warranty expiration may be eligible for goodwill consideration by the District Parts and Service Manager or your Zone Office. You must request consideration, and get a decision, before starting work.

INSPECTION PROCEDURE A

1. Access the air bleed screw on the throttle body.

2. Record the current setting of the screw:

^ Turn the screw clockwise, and count the number of turns (both full and partial) it takes to fully seat the screw.

^ Turn the screw counterclockwise back to its original setting.

^ Subtract the number of clockwise turns it took to seat the screw from 3-1/2. Record that number. Example: If it took two full turns to seat the screw, subtracting 3-1/2 from that gives you 1-1/2.

3. Start the engine, and let it warm up to its normal operating temperature (the cooling fan cycles twice).

4. Turn off all electrical items (A/C, audio unit defogger, lights, etc.). Center the steering wheel so there is no power steering load.

5. Connect the PGM Tester or HDS to the 16P data link connector (DLC).

6. Turn on the PGM Tester or HDS. Enter the VIN and odometer reading.

7. Follow the screen prompts on the PGM Tester or HDS to get to DATA LIST. Scroll down the list to IAC.

8. While watching the IAC counts on the PGM Tester or HDS, slowly turn the air bleed screw (either counterclockwise or clockwise) until the IAC count reaches 1 (or 7 for '99-00 Odyssey) or you have turned the screw counterclockwise a total of 3-1/2 turns. (Count the number of counterclockwise turns you have made, and add that number to the screw setting you recorded in step 2.)

^ If you see an IAC count of 1 (or 7 for '99-00 Odyssey), turn the screw clockwise 1/2 turn, and then go to step 9.

^ If you do not see an IAC count of 1 (or 7 for '99-00 Odyssey), and you have turned the screw counterclockwise a total of 3-1/2 turns, leave the screw set where it is. Go to step 9. You should never set the air bleed screw counterclockwise more than 3-1/2 turns from its seated position. If you set the screw further it could work itself out of the throttle body over time.

9. Let the engine idle for 10 minutes to allow the ECM/PCM to learn the new idle parameters.

10. Turn the ignition switch to LOCK (0). Turn off and disconnect the PGM Tester or HDS.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



NaymzJaymz
User

Jun 18, 2023, 2:08 PM

Post #5 of 7 (958 views)
Re: Honda D16Y8 Idle Screw Removal Sign In

Okay thanks for all the info. The P0505 code was present for weeks before I ever messed with the idle screw. I thought I mentioned that. It was just an effort to try and find some solution. I thought maybe an o-ring in there might have deteriorated or something. Obviously the wrong call.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jun 18, 2023, 5:10 PM

Post #6 of 7 (944 views)
Re: Honda D16Y8 Idle Screw Removal Sign In

Thoughts on this: Jaymz - Had a moment to search around if only to see what you've seen out there. On the right track that type of thing wasn't meant to be messed with.

Add age and frequent temp changes on dissimilar metals - uggh. That's a lot.

Similar basics to idle mixture screws only dealing with metered air thru the ports.

IDK the OE was probably a steel with fine coating of brass or similar.
Enough time on it. It's turning YOU said but quits. Ayup (slang) it got corroded just so that it could time won I think.

AYOR if you keep messing with it already been beat on as it wasn't meant to mess with - a cover of it but still on 24 years??

AYOR if you have time and $$ this could be off because of plain hole corrosion YOU said if only to clean it out. I agree, should be able to clean things out of the sort.

May not be able to or ruin that if you continue at least be ready ahead of time for new part(s) gaskets as required.

All test YOU said show no vacuum leaks by years are some that wouldn't show up with testing line holding vacuum anywhere if just stiff or cracked are leaking so slow impossible to really check. That you just toss wholesale.

Time to do if YOU work a 70 hr. job has to be limited - understood.

I'm done searching this physical thing bet "O" ring is more to keep moisture away than seal air IMO threads should be enough?

YOUR time, the trouble and risk of making it worse?

Just seeing the whole scene not just mechanical need waiting.

If somehow you could guess it hasn't been touched in all those years screw is a steel and alloys just don't cooperate that long.

New stuff fastest and costs matter.

If it runs well enough triple check everything else without the risks for now - your case not some instruction manual.

I'd bet it would bust or wreck threads the weaker the hole's threads so committed to fix/replace it.

Just thoughts on this rock and hard place I'd jump all over how many miles alone but know of these doing that many and be OK still!

I'm only aiming at cleaning it out hopefully a spray, brand Gummout matters is really best for some things still carb cleaner by name others are different.

It's you risk and think watching ports being open with spray may be the only way - said you risk making it worse and need more for trying.

You decide and roll the dice that it wasn't the issue and harmed it,

Tom



NaymzJaymz
User

Jun 19, 2023, 10:41 AM

Post #7 of 7 (878 views)
Re: Honda D16Y8 Idle Screw Removal Sign In

Thanks Tom,
I suppose I'm at the point where I will need to get outside help, and also put all the factors together(whether it's worth it to keep going with it).

Hindsight can be brutal sometimes. I was trying to fix it and learn something too. I was proud of myself for doing the head gasket. It failed the combustion leak test and is good now that way. The most extensive thing I've ever done.(all the P0505 issues were already there).

I was hoping that the head gasket change might help the idle issues in that there were exhaust gasses going into the coolant, but that obviously wasn't it.

I'm going to keep trying. I love the car. My sons got for me for Fathers Day a few years back. I appreciate all the help I've gotten from you and Hammer with all the questions I've asked here over the years.






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