.... Oh, I forgot to mention that I cleaned the throttle body as well. I believe I got all the connectors and hoses back to their respective homes. Also, at the same mile from home when all the excitement happens, I also got the CEL and VTM-4 love note.

 

In order of ease and affordability, first I'd...

1. I believe I got all the connectors and hoses back to their respective homes.

   ...recheck and reinsert them all, preferably after spraying in a little contact cleaner,
2. run a can of Seafoam through a tank of gas.

...then move on to more onerous solutions.

 

BTW - my Pilot ran okay before the tune up and I thought it pretty odd that without exception, ALL the valves were tight, so I adjusted them all to the middle spec (.022 Intake & .030 Exhaust). The plugs were all pre-gapped at .035 so I opened them to .041. When I started and test drove it, I noticed how the engine (usually quiet and smooth) sounded like a diesel engine with all the valve clatter, so I was concerned that I got that part wrong some how. Later, it sounded like it was settling in - a little quieter.

I was under the impression that the valve springs would push up the rocker arm, but almost to a valve, I had to push down on the cam side to get the gap to appear. I did not run into that experience when I adjusted the valves on my wife's Odyssey. That operation went according to plan and no problems arose.

Where did I go wrong?
Where do I start?

 

OEM plugs?
What codes are being thrown?
Maybe throttle needs reprogramming- you may have bumped the disc?
Triple checked each valve lash and corresponding with crank position?
Is it possible you damaged crank sensor?

Others will chime in that have more experience

 

Definitely double check all the hose are where they belong and that none of the vacuum lines are pinched.
Have you disconnected the battery and done an idle relearn? It is definitely needed after an TB cleaning possibly after a valve adjustment as well.
Was the valve adjustment completed on a stone cold engine?
Double check all electrical connectors are plugged in and seated.
Many of processes you did, you've needed to remove the intake pipe- is it fully seated and tight on the throttle body verifying no air leaks? Did you accidentally crack it while removing? (Common issue with these Pilots)
Grab the ratchet and go over every bolt you removed to make sure something isn't loose like the EGR.

These are some things to check and double check but I'd personally start with disconnecting the battery for a few minutes ( or can touch the positive and negative terminals together WHEN THEY ARE OFF OF THE BATTERY) connect the battery back up then start the vehicle and let it run for until the cooling fan cycles twice or about 10-20 minutes depending on ambient temp. Keep all accessories off like lights, radio, seat heaters, ect. If this fixes the issues, congrats! If not, keep searching for the issue.

 

Thanks Guys,

Yes Rusty, I did the adjustment on a stone cold engine.

I put my Blue Driver OBDII reader on this morning and got a code for Idle Control System (P0505). I cleaned the Throttle body but perhaps the IC valve needed more attention, so I pulled that off today, took it apart and cleaned it.

I will double check hoses and clean electrical connectors, but I did hear about an Idle Relearn on one of the videos I watched. They said to let the engine idle until warm (cooling fans on), THEN idle for two minutes with no AC on, THEN idle for two minutes with AC on, THEN idle for two minutes in DRIVE (AC on), THEN two minutes in DRIVE with AC off.

Does that sound right?

 

I got the IAC valve cleaned and reassembled (not sure I got the impeller in the right position, forgot to take a photo in the process) and installed, put it all together and fired her up for an Idle Relearn. Shooting in the dark, I just let it idle until it got up to temp. When the fan finally engaged it was 220 degrees (about 12 minutes), then the idle changed from the 1000 rpm to 1800 rpm revving, to a faster, shorter range (1200-1600). I had some place to be, so after 15-20 minutes, I had to shut it off. It did not seem to be settling in. Giving up and ordering a new IAC valve. Hope that fixes it.

 

Okay.... Second attempt: Replaced IAC valve with a new one, put it all back together, attached the battery and, after reviewing other posts regarding Idle (re)learning, I started the engine, held the idle at 3000 until operating temp (fan came on), then let it do it's thing for 10 minutes. Nothing changed - it still ramps up and down between 900 and 2100 rpm.

I made sure to check all possible electrical and hose connections. I even noticed that the PCV hose connection to the throttle body (underneath the throttle/Cruise linkages did not go fully on the nipple unless I pushed the circular linkage out to the way before pushing on the hose and hose clamp. I thought that perhaps my previous connection was causing a vacuum leak.

On a previous post here inre: to Idle Learning, one member said that first you had to use a bi-directional scan too to reset the throttle position, but nobody else ever mentions it at all. The discussions also talk about the car eventually adjusting itself slowly over time (part of its function to allow for carbon build up), so unless somebody here has any other suggestions, I guess I will try the "slow" method next.

 

a bi-directional scan too to reset the throttle position

If you want to give that a shot, here's a good scan tool that reads Honda-specific codes. It's not too expensive. See what codes you might get.

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I've never had to use it to reset the throttle position, though, so contact the company here to ask if it can do that, or if not, which model(s) can.

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www.foxwelltool.com

 

When ever a throttle body is cleaned, it should be reset to factory settings. Some say this can be done manually, I've only ever done it with a OBD II scanner with service functions.
Glad you got it going.

 

Can you please let us know which hoses were misplaced so others have the knowledge for what to watch out for in the future. Thx