Date:         Fri, 10 Jul 2015 09:40:23 -0700
Reply-To:     Tyler Hardison <tyler@SERAPH-NET.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Tyler Hardison <tyler@SERAPH-NET.NET>
Subject:      Throttle Body - High Idle - (Dare I say?) Issue Resolved! (85
              1.9l)
Content-Type: text/plain; charset=UTF-8

While I cannot say that my experience would be the same as everyone else's
if they followed what I did; I can say that my high wandering idle is gone
and the van is happy.

So, in another thread, I "me too'd" another thread where Steve Williams
noted that he was unable to get the van to idle down after warmup. I cannot
find any follow up as to if he was able to resolve the issue, so I'm
relaying my experience in case anyone else has a similar problem in the
future.

Last Sunday while I was replacing the fuel lines, I decided to go ahead and
remove the throttle body to get a closer look at my unit and to give it
thorough cleaning.

Upon removal I could not detect *any* play in the butterfly valve or shaft.
Previously I was told to "pull up and down" to detect play. I also wiggled
in other directions and even reached in the throttle body to see if the
butterfly valve itself was loose. I'm happy to report that I could not
detect any worthwhile play in the multiple manipulations of the unit. *(Note,
that if you're at this point and you do have play, you probably should stop
here what I've done after this won't help that).*

Ok, wonderful! I won't have to ship it off to be remanufactured! (1.9l
throttle bodies are almost nonexistent)

Tools needed:
* Flat head screw drivers (one large for idle screw, one small for careful
compression washer plying)
* Carb dip, comes in a can, costs about $30. Alternatively you can use carb
cleaner but this can get messy.
* Shop rags for wiping and drying.
* A relatively clean workspace in case you drop a small part.
* A timing light with a tachometer. Not critical if you have a friend or a
shop that can set your idle.

Parts you should have:
* A new throttle body gasket (it's cone shaped).
* Assorted rubber rings in case the idle screw seal is damaged.
* A short piece of vacuum line.

TB: Throttle Body.

I'm assuming that you've already removed the TB (this is easy). This is
just something I did, and I cannot be responsible for your unique
situation. No warranty, YMMV, etc. The key thing to "being mechanical" is
to be observant. Observe the position of the idle screw, observe the
position of the throttle cable. Heck, take a picture, draw a picture, have
your friend with the photographic memory handy. When you're reassembling
later, these observations will make you a pro.

So I disassembled all of the parts that were rubber or plastic. That means:

1. Remove the idle switch (1.9l there is just one). This is done by
carefully plying the compression washer free where the cam that activates
the switch sets. I'll refer to this as the "main shaft".
2. Slide off the cam (it will take some wiggling and possibly *GENTLE*
 plying).
3. Remove the set screw that is holding the switch in. Do this with the TB
right side up and *hold the switch in place.* Now turn it over.
4. Carefully slide the switch off. There is a concentric cam that is for
adjustment of the idle switch. It is tiny and lost easily. If you have the
TB upside down and are lifting the switch off, it should stay on the TB. If
you don't see it, your TB is dirty and it's stuck to the switch. Carefully
turn the switch plate over and locate it. Set it in the parts basket for
the carb dip, or put it someplace safe. *If you lose this part.. I don't
even know what to do.. FIND IT.*
5. Set the plastic parts of the switch behind, carb dip and
rubber/plastic/anything not metal do not mix. Best case, you just scar the
plastic and make it brittle. Worst case you got some carb dip from the 70s
and the plastic has disappeared.
6. Turn the unit back over and remove the idle screw. It is fine threaded
so expect a few turns. Observe the number of threads visible, and the
position of the screw. This will not be an exact science, but will put you
into a good starting position for later.
7. Inspect the rubber gasket (ring). If it is not supple, as in its dry,
cracking, etc. Remove it and replace it later. I buy these things in
assorted bulk from hardware stores and always seem to have the right size.
If it looks fine, set it aside and *DO NOT SOAK IT. *You can hand clean
this part later.
8. Inspect the TB. Look at the vacuum port, does air pass easily through
it? The throttle plate and "throat" are they clean? (Mine was a mess).
9. Drop the screws you removed, and other pieces you want to clean into the
basket and lower it into the dip. In my case I had to run some steel wire
around the TB. It was too large for the basket and fishing in carb dip is
not fun. All covered? Is the smell bothering you? Go get some fresh air.

In my case, at this point, I went back to do the fuel lines on the bus. (
http://www.vanagon.org/fuel-line-replacement/) Which took me a few hours as
I was being anal and inspecting everything I could along the way. I also
took the time to clean around the area where the TB sits.

.... and now we're back to the TB.

1. Have something to set the wet parts into. (Wife's cake pan?) Kidding..
(Did I mention that I am not responsible for divorce either?) I have an old
litter box from a long gone critter.
2. Inspect the parts. In my case it came up completely clean. Use your shop
rags to wipe off each part. Use your short piece of vacuum line to blow out
the vacuum port.
3. I used a tiny bit of water to wash out the throat. A plastic spray
bottle is neat.
4. You might still have some gunk in some places. I used carb cleaner and a
rag to get at these. The important part is that you get all of the carb dip
out of the unit. It is a solvent and I don't want that in my engine.
5. Clean the idle switch and related parts up. Again, Seafoam and a rag.
6. Clean the idle screw up. I used a little bit of Seafoam on a rag and
worked off the gunk.
7. All clean? All dry? Let's go!
8. Look at all of the parts! Start off by replace the concentric adjustment
cam back into it's home.
9. Slide the switch into position, you might have to wiggle the cam around
to get it into position. Don't worry, we'll adjust this later.
10. Replace the cam on the main shaft (it should be obvious on the
direction, the cam points toward the switch).
11. Gently tap the cam into place.. Again tight fit.
12. Flatten the compression washer ever so slightly and push it back down
to hold the cam in place.
13. Hold the switch in place, and turn the TB back over. set the set screw
into place but do not fully tighten it. At this point I adjusted the switch
on the bench according to the Bentley. Feeler gauge and all. I found it
MUCH easier when it was sitting in the vice to do so.
14. Screw in the idle screw. Refer back to your picture of it's position
before. The important part is the depth and final position of the screw
head.
15. Inspect the assembled unit. I checked for play again. Still good!
16. Carefully install back into the bus with the new gasket.
17. Reinstall your air cleaner, etc.

At this point I primed the fuel system and started checking for leaks from
the fuel lines. I cycled the pump about 12 times to ensure that things are
not going to explode.

Funny moment for me here, I had removed the coil wire because it annoyed
me. My first turn over resulted in nothing, and I had that panicked pit of
your stomach oh no what did I do.

Reinstalled the coil wire, and fired up the beast. I had turned my idle
screw too far in and it wouldn't idle after start.

I opened up the idle air screw a bit and boom.. idling.. (a bit low, but
idling) Powered off.

Hooked up the timing light and tach.. Bypassed the idle control unit, and
started her up.

At this point, you have to wait for the bus to reach operating temperature
(according to the Bentley) before checking timing/idle. So I got a cold one
and just wandered around looking for any signs of fuel leaks.

Checked the timing: Good.
Set the idle: ~950 Check

Waited.. Still idling normally, so sign of a rising idle.

Closed up engine and went for a drive.

Idles like she's supposed to now!

Ok, so what gives.. Why was this an issue? How could a cleaning resolve
this.

Two things that I believe were at the core of the issue:

1. The idle air screw was pretty gunky and dirty. I mean the thickness of
my bladed screw driver type of gunk. The idle was set with that in place..
So.. not accurate. (Previously when I set the idle it was VERY difficult to
hit that ~950 number)
2. The TB's gasket was flat and doubtful that it was making full contact
around the circumference which also added uncontrolled air into the mix.

Other "new" behaviors that the van has now:

1. Morning idle is what I expect it to be. Around ~1200 Rpm for a short
period then it idles down to normal idle. Before it would sometimes die or
just be "off" until warmup.
2. Returning to "idle" state when coming to a stop seems smooth.
3. That midpoint between "fully warmed up" and "fully cooled down" no
longer feels like the van is struggling to get up to speed on acceleration.
The power curve seems consistent despite the van's current operating
temperature.

Whew, sorry for the long article, but hopefully this will help someone else.

-t