1978 Westfalia - Won't Start (long story) and "Hi"

[Amskeptic]

Before I get into this even more (it sounded great today when I ran it a little bit... reasonable rpms while warm, timing still looks good), can't all of this stuff be checked now with an exhaust gas analyzer? How much would it hurt to drive this thing a little bit to a garage?

I wrote a great speech last night about the limitations of exhaust gas analyzers and the people who use them. Then my processor overheated and shut this laptop down. Several little screws and bits of plastic later, the dual scroll fans were cleaned and the clot of dog hair from previous owner was removed from the finned heat-sink and laptop is back together running cool. Yay.

Truncated Speech:

Exhaust gas analyzer + those who operate them will commonly not have a clue about what to do. You are in a forced IAC Fuel Injection Doctoral Program that vaults you past trained mechanics. They have not been trained in Inside The Air Flow Meter, nor have they been trained to provide you anything but a weak turn of the mixture screw before they indict your AFM for being defective. They also have to follow published emissions guidelines that may be fine for a new engine but lean for our old engines. If they actually speak knowledgeably of the wiper adjustment/black cog adjustment matrix, have at it. Let us know. Otherwise, we are close to the final mixture adjustment which we do at 3,000 rpm, recheck idle mixture, trim mixture screw and yer done.
Colin

[Old McDonald]

Before I get into this even more (it sounded great today when I ran it a little bit... reasonable rpms while warm, timing still looks good), can't all of this stuff be checked now with an exhaust gas analyzer? How much would it hurt to drive this thing a little bit to a garage?

I wrote a great speech last night about the limitations of exhaust gas analyzers and the people who use them. Then my processor overheated and shut this laptop down. Several little screws and bits of plastic later, the dual scroll fans were cleaned and the clot of dog hair from previous owner was removed from the finned heat-sink and laptop is back together running cool. Yay.

Truncated Speech:

Exhaust gas analyzer + those who operate them will commonly not have a clue about what to do. You are in a forced IAC Fuel Injection Doctoral Program that vaults you past trained mechanics. They have not been trained in Inside The Air Flow Meter, nor have they been trained to provide you anything but a weak turn of the mixture screw before they indict your AFM for being defective. They also have to follow published emissions guidelines that may be fine for a new engine but lean for our old engines. If they actually speak knowledgeably of the wiper adjustment/black cog adjustment matrix, have at it. Let us know. Otherwise, we are close to the final mixture adjustment which we do at 3,000 rpm, recheck idle mixture, trim mixture screw and yer done.
Colin

Sounds good... I will let you know what happens in the next couple days (when it gets over 20 degrees finally)

[Old McDonald]

1. Mixture screw turned 7 times before it seated...
then I put it back where it started (7 turns before)
2. After I nudged the needle a little bit, it kept running and seemed to be running ok... the RPM was in a good range, timing perfect.
3. Nudging the wiper a little clockwise/counterclockwise seemed like it didn't do anything to the revs, so I assume it may be okay. If YOU feel I am ready, I am ready for the next step!

So it is idling by itself when warm at a decent rpm?

1. Mixture Screw Forensics: based on your information above, none has tried to hide a vacuum leak by running to that screw. This is good. Please take two and a half turns clockwise as our initial value on the mixture screw. This places us exactly in the middle of its possible adjustment range.

2. With a fully warm engine that has even had a chance to drive down the road for a good 20 minutes, re-check the wiper by the aforementioned little nudges, but see if you can read a tach-dwell meter while nudging. Try to get the most optimal rpms you can +/- 25 rpm. Even an analog meter can be very accurate if you can discern a needle on one side of a hash mark moving to the other side. You do not need to actually have the needle directly over a hash mark on the scale, you can just move your eyeballs to either side of the meter until you see the needle appear lined up. After you lock your eyeballs at whatever angle was required to have the needle lined up with a hash mark (note that I don't really care what the actual rpm is, we are just trying to catch a subtle change), gently move the wiper in either direction to catch the Very Most Optimal RPM you can. If you then tell me that you gained 25 RPM when you pushed the wiper counterclockwise, we will note, you and I, that the idle is slightly leanish but do nothing about it yet. If you find that you gained 25 rpm when you nudged the wiper clockwise, we will know that it is slightly richish. Move the wiper some more in each direction if you got no noticeable change in rpms. You WILL drop the revs in BOTH directions if you get ham-handed about it, that's OK too, just tell me if the distance-to-rev-drop favored CW or CCW.

As a preamble to our AFM adjustments, just lightly read the below to prime your mind to start working on the concepts subconsciously.

The AFM provides a complete matrix in the three possible adjustments provided:

A) the wiper hold-down screw inside that little oval slot I call the
Static Adjustment

B) the black cog with the teeth around its perimeter I call the
Dynamic Adjustment

C) the mixture screw I call the "trim adjustment" this week.

Between the three adjustments, we have the ability to affect the entire matrix, i.e. the mixture map.

Rich.
.......
.......
.......
.......
.......
Lean
. . . . ........................................................
Low RPM/Load . . . . . . . . . . . High RPM/Load

Since this current php site code is stuck on "left margin" I can't draw you a graph. Use your imagination. Imagine a direct 45* line from lean/low up to rich/high. That is a simple fuel consumption curve in a perfect theoretical world.

Your static adjustment (A) will move that line up or down maintaining the perfect 45* angle at all times. If you adjust the wiper CCW by loosening the hold-down screw and easing it over a tooth, you move that line up towards rich. Low speed/load, high speed/load, doesn't matter, the engine's entire experience gets richer.

Your dynamic adjustment (B) changes the slope of the map. Imagine a nice curve up towards "richer sooner", or imagine a curve towards horizontal which is "leaner later." If you rotate the black plastic cog (by prying the chrome lockwire away from a tooth with your regular screwdriver tip and rotate the cog CCW (richer) or CW (leaner) you either unwind the spring coiled in inside, or wind it up still further.
This adjustment primarily affects the higher rpm/load.

If you play with this adjustment, there will be some "blowback" on the idle adjustment which you then take care of the mixture screw.
Colin
(notice how I have not yet offer a procedure. . . . . .)

I finally got around to this.
1. I rechecked the vacuum hoses to make sure nothing is still wierd on that end. Things look pretty good.
2. The nudging of the needle did not hardly do anything different. The only thing that happened of note is that the bus would just die once I moved the needle in either direction enough. It still kind of runs like shit (once in a while it drops a tiny bit of rpms... just a real tiny bit, or goes up a little bit... nothing huge); the RPMs, once warm stay between the 900-1050-ish range. Timing is dead on. Again, nudging needle seems to do nothing for the rpms.
3. I set the idle screw dead center, like you said.
What is next?
Thanks
OM

[Old McDonald]

Any suggestions? Help please???
Thanks-
OM

[Amskeptic]

Any suggestions? Help please???
Thanks-
OM

Sorry, I had a family emergency to attend to. Still do. So, you got back to me 25 days later, and I got back to you within 9, we're cool. AIN'T WE?

If nudging the needle subtly in either direction causes absolutely no change in rpms, you idle mixture is good. Verify with a tach-dwell meter that you get the same amount of movement in either direction before any change in rpms is noted. We would prefer that moving towards lean CW causes a sooner drop in rpm than towards rich CCW.

So now we have to check the high speed rpm. Bring engine to 2500 to 3000 rpm and hold it there with whtever mechanical means you can. A screwdriver expertly wedged is good. Sit and watch the engine hold that speed consistently. Now gently nudge the wiper barely 1/16" of an inch (maybe 1/4" if no noticeable change) CCW. Revs go up? Or do they go down? Now nudge CW 1/16" (or 1/4" if no change was noted). Revs go up? We want to know if any of your nudges brought revs up. . . Remove screwdriver when done. My site attorney told me to tell you that.
Colin

[Old McDonald]

we're cool. AIN'T WE?

Yes. Please don't hurt me.

Anyway, got the RPMs up to 3000, and the revs went up when I turned the wiper CW, but not CCW
OM

[Amskeptic]

we're cool. AIN'T WE?

Yes. Please don't hurt me.

Anyway, got the RPMs up to 3000, and the revs went up when I turned the wiper CW, but not CCW
OM

Look! 20 days! Things are looking up here in this Most Amazingly Slow Thread Ever.

OK, I really want us to be accurate here. Rarely do we find an engine that revs UP when you nudge the wiper CW. That suggests a very rich condition.
But, be that as it may, you'll want to adjust the black cog CW as well, until there is no rev up when you nudge the wiper CW. Try a 6 tooth increment to start. Let me know. . . before February 16th.
Colin

[Old McDonald]

No more rev. I adjusted the cog back and forth until it was precise.

[IFBwax]

Woo Hoo!!!!! How's it run now?

[Amskeptic]

Yeah, how's it running now? Your brief update, it is like a mid-sneeze. . .

[Old McDonald]

I think it runs a little better... at least it starts and stays running. The smoke from the exhaust still seems a little white, but a lot of that could be from it never getting over 30 degrees around here the past month or so.
I still need tot ake it for a drive, which will happen after I get done moving. I will update this with the results of the test drive but it won't be for a little bit.
Thanks for the help.

[Amskeptic]

I think it runs a little better... at least it starts and stays running. The smoke from the exhaust still seems a little white, but a lot of that could be from it never getting over 30 degrees around here the past month or so.
I still need tot ake it for a drive, which will happen after I get done moving. I will update this with the results of the test drive but it won't be for a little bit.
Thanks for the help.

Depending on where you move to. . . I'd be happy to give you a half-day with guaranteed results, you know "no ticky no payee"

White vapor is usually condensation from combustion. When the engine is fully warm it should go away. If you are in an Arctic climate presently, look at the cars around you for comparison. If everyone has vapor trails, don't worry about yours. These air-cooled cars can warm up very slowly or run cold if the thermostat is not closing when cold.

A drive, a nice long bonding drive is only a good thing for your car.
Colin