Another dwell question

[OG Velvet]

So it's been a couple days. Been raining like hell in Portland.

I went out and put the alternator belt back on. Tightened a bit. Started it up and took it out to test Colin's theory. It ran perfectly. No studder or bucking. I got on 2nd and 3rd hard. No problem. Let it warm up for about 20 minutes after that. Took it out again. Ran perfect. I'm feeling pretty good at this point.

An hour and a half later I jump in it to run an errand.

Same BS. Starts great. Then the idle starts fluctuating. Then the idle drops and it dies. But it will start right back up. I haven't taken it back out yet. (I had to get somewhere). I plan on doing that when I get home.

Bummed
_________________
'67 13 Window
'77 Westy
'69 Sunroof Beetle
'65 Honda Dream

[OG Velvet]

So I got home and took the bus out again. I took off cold with no warm up. I ran all over varying speeds. I drove around for about 25 minutes.

It ran perfectly.

I'm going to drive it to work tomorrow. I guess I'll see what happens.
_________________
'67 13 Window
'77 Westy
'69 Sunroof Beetle
'65 Honda Dream

[Tom Powell]

Be sure to have your raincoat, AAA, and bus pass.

Best of luck and good fortune.
Aloha
tp

[OG Velvet]

As always, I appreciate the help from everyone. I love this place
_________________
'67 13 Window
'77 Westy
'69 Sunroof Beetle
'65 Honda Dream

[Wildthings]

If you haven't done it yet take the white wire that runs from the ECU to the TSII sensor and ground it out to the block once the engine has run a few minutes to warm up. Now take it for a spin and tell us what it runs like.

[telford dorr]

Opinions:

- the old distributor play, while not great, is typical, and shouldn't be causing your problem.

- the new distributor advance is bupkis - return that unit to where it came from, and request one that works.

- the points coloration is fairly normal - don't think that's the issue.

- the voltage at coil terminal 15 should be rock solid. If it's not, fix that first. If removing the alternator belt makes the voltage steady, then the alternator / regulator /interconnect harness needs attention. Do a sanity check and try a different voltmeter, to make sure you're not chasing your tail.

- sounds like a fuel delivery problem to me. Here's where a LM-2 fuel ratio meter would give you a quick answer, one way or the other. Without that, I'd do the following:

1) measure the fuel pressure at the test port and see if it's correct, and varies properly with throttle opening.

2) get a can of spray contact cleaner. Unplug every FI connector (including grounds, double relay, and computer), and give the contacts a good shot of cleaner. Reassemble. Look for marginal or broken wires and bent, damaged, or pushed out pins.

3) check the resistance of Temp Sensor #2, and make sure it's right.

4) inspect the "S" boot for cracks or damage. An air leak here will really mess up the engine performance. Actually, any intake manifold leak will, so check all the widgets connected to the "S" boot.

4a) inspect the 4 intake manifold coupling sleeves for integrity.

An ignition problem typically presents as a miss, or other quick engine speed variation. Fuel issues typically present as a RPM or power fade. Leanness will cause intake backfire and bucking.

For what it's worth...
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST)

[1975 Kombi]

The old distributor is missing a fibre washer on the bottom I think. They usually breaks and fall out and add vertical play to the shaft. It bounces Dwell around a bit with vertical play.
_________________
Brett

“He’s decieving you boy! Reach into his pocket and take what he’s got.” Mr. Crabbs.

75 Westy auto
03 Jetta TDI
71 SB
74 Westy
Licensed pilot (single engine land VFR)
--
Rust In Pieces: 72 Bug, 73 Bug, 81 Rabbit LS D 2D, 83 Rabbit D 2D, 84 Jetta TD GL, 85 Jetta D, 68 Z28 RS 302, 91 Passat 16v

[kreemoweet]

[OG Velvet]

F?ck.

Drove perfect to work. (About 4 miles)

Just jumped in to run to a meeting. Bucking all over the place. Totally undrivable.

Hopefully I can limp it home again in a couple hours.
_________________
'67 13 Window
'77 Westy
'69 Sunroof Beetle
'65 Honda Dream

[OG Velvet]

The bucking is not just under load anymore. It's sputtering at idle and when I rev it up.
_________________
'67 13 Window
'77 Westy
'69 Sunroof Beetle
'65 Honda Dream

[1975 Kombi]

[OG Velvet]

[1975 Kombi]

Is the issue humidity or temp or temp/dew point related.
_________________
Brett

“He’s decieving you boy! Reach into his pocket and take what he’s got.” Mr. Crabbs.

75 Westy auto
03 Jetta TDI
71 SB
74 Westy
Licensed pilot (single engine land VFR)
--
Rust In Pieces: 72 Bug, 73 Bug, 81 Rabbit LS D 2D, 83 Rabbit D 2D, 84 Jetta TD GL, 85 Jetta D, 68 Z28 RS 302, 91 Passat 16v

[OG Velvet]

I'm not yet sure if this is correct...

But let's say what if, the issue only was happening when it's raining balls outside? (been a lot of that lately) What could that mean?
_________________
'67 13 Window
'77 Westy
'69 Sunroof Beetle
'65 Honda Dream

[1975 Kombi]

My neighbours Harley had something like this and anytime there was a close temp/dew point it would coat his bike in little dew drops and run bad. So I told him to start it in the dark on different nights and sure enough he had a small crack in his coil on the bottom by the frame and in the dark on some nights he noticed a blue flame/spark arc to the frame. He replaced the coil and Bob's your uncle. Fought with it for the whole summer.

So turn everything off and in the dark and watch for anything arcing. Just another thing to check. You might have a wire somewhere that the rubber coating is cracked and arcing and will only arc when the humidity is high.
_________________
Brett

“He’s decieving you boy! Reach into his pocket and take what he’s got.” Mr. Crabbs.

75 Westy auto
03 Jetta TDI
71 SB
74 Westy
Licensed pilot (single engine land VFR)
--
Rust In Pieces: 72 Bug, 73 Bug, 81 Rabbit LS D 2D, 83 Rabbit D 2D, 84 Jetta TD GL, 85 Jetta D, 68 Z28 RS 302, 91 Passat 16v

[Tom Powell]

A weak ignition system may be affected by humidity or rain.
There are many places the ignition system can be weak, but the high tension wires and their contact points are the first suspects.

As just posted, check it in the dark. Very dark.
You may see gremlins dancing around their playground.

Aloha
tp

[OG Velvet]

[Tom Powell]

If the ignition system is wet and compromised it can be dried with LPS-1 spray.

"LPS 1® Greaseless Lubricant is specially formulated to penetrate minute crevices, displace moisture, and leave behind a thin, dry lubricating film. It is the top choice for drying out critical electrical/electronic components and lubricating precision instruments."

Displace moisture are the key words. Buy a spray can or bottle and next time it starts bucking spray everything from the coil to the plugs and in between including the inside of the distributor cap, but not on the points. Also check the inside of the distributor cap for carbon dust buildup.

Here's a thread that gets a bit off track, but related to moisture and humidity.
http://www.thesamba.com/vw/forum/viewtopic.php?t=6...mp;start=0

Aloha
tp

[Tcash]

[OG Velvet]

I will look for fireworks tonight. But of course now it's running great.

I did find a spot on the #1 FI wire that had worn through. Unclear if it was enough to arc out. I taped it up pretty good. Couldn't find any other obvious breaks.

Thanks again for sticking with me here.
_________________
'67 13 Window
'77 Westy
'69 Sunroof Beetle
'65 Honda Dream