I am amazed, and Oh Darn

Apr 06, 2004 47 Replies

I am amazed. The Wonderbus started. I almost fell over in surprise. Needed some timing adjustment, a little carb idle fiddling. But it sounded good. Smelled good, too -- like a good mixture.



Strong -- the new SVDA dizzie makes a nice improvement. Timing light showed it advancing as spec'ced in the instructions.



However and alas. After 15 minutes of driving, it died. I've had to run a bunch of errands so I have not been able to do any testing. While waiting for the AAA driver to show up and flatbed us back home I poked at the engine and looked for loose bits, wires or hoses and nothing obvious. I'll do more testing tomorrow.



But I do have one clue and this might provide someone with an idea of a good place to start: about a half mile before the engine died, the tach started getting spastic. Spiking up randomly. I listed to see if the engine was doing the same thing, but it was running smoothly. I was driving on level road at a constant speed. The crazy tach worsened, then plummeted to the "0" setting and the engine died along with it with the oil and gen lights on. As we pushed it to a safe place I noticed that the brake lights worked, so we do have power.



The tach gets its signal from the same terminal on the coil that connects to the dizzie.



One thing I noticed: when I took the coil off to work on the engine, I carefully labeled all the wires. Green dizzie and green to the aftermarket tach went to one side of the coil. Side labeled "+". There were two other wires, which went to the "-" side of the coil. Hmmm . . . wait a minute here -- Aircooled's notes said the dizzy (and tach) go to the "-" of the coil. Wiring diagram is not helpful, saying "1" and "15". This is how the coil was wired when I got the car. Might I be dealing with a blown up Bosch 12v coil?


put some gas in it once in awhile ;)

Oooohhhhhh. I am /such/a knucklehead.

surprise.

fiddling. But it

Timing light

I've had to run

testing. While

home I poked

and nothing

an idea of a

died, the tach

see if the

smoothly. I was

worsened, then

with it with the

noticed that

coil that

the engine, I

the

labeled "+". There

coil. Hmmm . . .

(and tach) go to

"1" and "15".

be dealing

VW didn't use + and -, they chose to use 15 and 1 instead.

1 = -

15 = +

John Aircooled.Net Inc.

It's too dark outside to check, but I have this sneaking suspicion that the car came with a backwards-connected coil, and I carefully labeled my wires that way, and then hooked the coil up backward. I'll ohm it out tomorrow and see if it has been damaged. Check the points, too -- my handy-dandy dwell meter said they were a bit too far apart anyhoo.

Check also all the wires for braking or grounding. This tachometer behaviour you describe suggests that there might be a loose connection somewhere or wire cut. Burned points is another option. Check everything.

On Mon, 05 Apr 2004 23:01:00 -0700, "Mike Rocket J. Squirrel Elliott" ran around screaming and yelling:

Olli is correct in it sounds like it could be a grounding problem on the tach wire...your engine *WILL* run and run fine with the coil hooked up completely backwards(meaning that everything that needs to go to + goes to - and vise versa)....since you don't have a choke element to worry about then being hooked up backwards *should* not be your problem(but *could* be...hehe)....since a break in the tach wire would ground the coil also this would act as a "killswitch"...i chased this demon for a few months year ago when i bought a 74 beetle....going down the road and BAM....engine just quit...mess around(just checking) and then it would run fine...was very frustrating, untill i found it...I should have checked the entire wire to start with but thought it a longshot....surprise... JT

Good thinking. The test here would be to disconnect the wire to the tach at the coil. The voltage at that coil terminal normally bounces up to

+12 then to ground as the points open and close. The faster the cycling, the higher the rpm, and the tach indicates this. If the wire to the tach were grounded, no bouncee, no sparkee. Disconnect the wire, you got bouncee. Tach wiring can be troubleshooted (troubleshot?) at leisure.

I'm not clear about Olli's suggestion to check braking wiring, though. Unless brake pedals are depressed (I feel /so/ depressed!) then there is nothing electrical going on at the brakes, n'est pas?

[snip]

A comment: I was pleased that AAA sent a flatbed. While waiting for the driver I was thinking, "Dagnab it! I wish I had memorized the official tow points on this bus!"

Which brings me to a question: what is the official way to tow a bus, if a flatbed is not available?

On Tue, 06 Apr 2004 06:06:02 -0700, "Mike Rocket J. Squirrel Elliott" ran around screaming and yelling:

break in wiring.... JT

Now that it's light outside, I've traced the trouble to an intermittent problem in the new SVDA distributor. Connecting a voltmeter to the green lead feeding the dizzie from the coil and turning the crank by hand showed that the points seemed to be permanently closed -- no voltage ever. Took top off dizzie and inspected mechanical action of points: open and close visibly. However, pressing down the terminal where the coil wire attaches to the points assembly created a connection to ground. This is the highest point on the points assy. Putting the cap and rotor back on w/o the dust cover that sits under the rotor gave good points action. Installing the dust cover and the action was bad: always grounded. Taking cap and rotor and dust cover back off and examining things gave no indication of what the problem might be. Putting all things back back on and the points action is good. Great. I love intermittent problems. NOT! Sheesh. I must be brave and proceed with driving. Must get back on horse that threw me.

Not sure what dizzie you have, but check that the points are installed properly to place and that the possible ground strap from the points plate to the distributor body is not touching the points. Does the dust cover press the wire(s) inside the dizzy down? It might bend them so that something touches wrong things.

Shooting in the dark again.

SVDA (See above). From Aircooled.net

Keep the pointy end of the barrel away from me, then.

Will inspect new dizzie.

UPDATE: On the way to my local VW supply shop (Jbugs in Oceanside CA, I can recommend them) the same problem happened: spastic tach reading, engine died. Cranking gave indifferent (read: "crap") results. Cranked the engine by hand and measured points opening and closing. I stuck an old spark plug on one of the plug wires and drew a spark to the chassis. Yet no joy in startsville.

Pulled the new SVDA dizzie and stuck in the old 009. Had enough sense to rotate the new to TDC and cylinder 1 (I'm getting better at this) before pulling new dizzie. Cranked the engine and it started. Fine-tuned the

009's timing a bit by hand for smooth idle (should-a packed my timing light).

Drove the Jbugs, got the bits and pieces I was looking for, drove home with no trouble. I'm pretty sure the new dizzie wants attention. Will poke and probe it, unless John at Aircooled just wants to swap it out.

But hey -- guys - I'm learning a lot and getting better at recovering from mechanical issues.

Oh -- one more thing. I was not mistaken: the 009 is a lot more sluggish than the SVDA.

Thanks for the congrats! The dizzie issue seems to be deeper than just stuck points - see my update. I will solve this. I will, I will.

Is the distributor green wire in ground potential all the time when this "not running" condition is on and you rotate the engine and the points open?

If it runs for 15 minutes and then dies, it might be heat related. It it is grounded all the time and you see the points open, there is a short circuit inside the dizzy or the condensator shorts when it heats up.

On Tue, 6 Apr 2004 16:52:54 +0300, "Olli Lammi" ran around screaming and yelling:

My hat is off to you and jan and others for your english....better than most American's..... JT

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