Electrical Anomoly

[RONIN10]

Search seems to indicate this is a first or rarely documented effect. That or I am really just stupidly overlooking something obvious that everyone else has in their pocket already.

So I'm out working on my 69 bug last night and I connected my timing light to double check the timing (powering it off the + coil terminal, grounding it on the engine decklid hinge) and when I pulled the trigger to start the strobe light working, the whole engine bogs down. The light still fired when it was supposed to but I could only pulse the light in order to not completely kill the engine. It seems like there is some electrical fault in play here. Electrical is a bit of a nuisance for me and I'm currently fighting other battles on the vehicle so I don't have the time to systematically troubleshoot if it's possible someone else has the magic key to understanding. Any thoughts?

And this may be related: I did rework the fuse box wiring a few weeks ago as it was all goofed up from the previous owner, but I made certain to rewire it per the wiring diagram in my Bentley manual and now everything is back on it's proper circuit. All is working as it was before I tinkered with it with the exception of my oil pressure light not lighting on the speedometer. Something did go awry during the rewiring effort there. I suspect the wire between the sender and the speedometer is bad (99% original) as I know the bulb is good and I can't get the wire to arc when disconnected from the sender. Still, I thought I should add this for reference.

Any help is appreciated. Thanks!
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Andrew

Oscar: 1976 Westfalia Deluxe Camper, 2.0L FI, Manual Transaxle

[splitty_smile]

What is your voltage at the coil?
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---1976 standard bus "The Red Toad" transplanted 78 FI 2.0, Hydraulic lifters

---1974 Super Beetle "Gus" 1835 Engle 110 Dual Kadrons

[RONIN10]

[DrDarby]

The timing light gets connected to the B+ terminal on the gen / alt and ground but you should have battery voltage (or close) at the poitive coil lead when disconnected from the coil.
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Midwest Autosavers, Inc. Woodstock, IL

[RONIN10]

I've heard about connecting at the generator as well, but always got the impression that it didn't really matter which method you used. In the past, on other cars, I've always had the battery conveniently at hand so this situation never presented itself. Still, when I've timed this engine previously (about a month or two prior was the most recent instance) I've not had any trouble using the coil mount. Is this as simple as saying I need a new coil or is there the possibility that I've just stumbled onto some upstream effect and am just noticing it at the coil? In my experience, when most electrical parts fail, they just fail completely rather than peter out.
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Andrew

Oscar: 1976 Westfalia Deluxe Camper, 2.0L FI, Manual Transaxle

[bugninva]

if you only have 5.9 volts at the coil, you have found your problem...you are actually lucky a 12 volt coil will fire enough to run the engine at that voltage..
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[RONIN10]

I figured as much, but there's always that little bit of me that hopes there's a loophole to keep me from shelling out cash I don't have. Will replace the coil and see what happens. Worse case scenario, I suppose, I've got a spare.
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Andrew

Oscar: 1976 Westfalia Deluxe Camper, 2.0L FI, Manual Transaxle

[Bashr52]

If the coil works and there is only 5 volts to it, the coil is fine, you have a wiring problem. Would hate to see you spend money on something you dont need!

[Calex59]

[Mr. Loaf]

And, to check your oil pressure wire, ground the wire at the sender with the ignition turned off. Go to the light on the speedometer and read the wire to ground using an ohmeter. If you read "0" ohms your wire is good from end to end. Any thing else and the wire opened or shorted to metal. If you can find out where it is shorted to metal you might also find out that your coil wire is partially shorted at the same place. One more thing. Did your light ever work before you repaired the wiring locations. If it did not did the PO use tape on the sender threads? The sender needs to be threaded into bare metal to properly ground itself.
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Never drive faster than your Angel can fly
$24,100 was too hard to resist.................

[RONIN10]

Read in Bentley that condensor can affect the ignition voltage so I checked that this moring and it checked out all right. Which leaves me to check the following today:

1. Check firing on all four plugs (just for my peace of mind, I'm having off idle, under load carb adjustment issues too)

2. Check voltage regulator

3. Check oil pressure switch wiring.

Anything other suggestions? I'll report back my findings.

EDIT:

Used the timing light to see that current is indeed flowing through all four plugs. It doesn't sound like it's missing a cylinder and the plugs themselves were fine about a month ago, I'm not going to pull them and double check.

Voltage at regulator was 11.7 V steady. Still working the verification of the oil pressure switch wiring and the carb adjustment. Damn H30/31.
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Andrew

Oscar: 1976 Westfalia Deluxe Camper, 2.0L FI, Manual Transaxle

[Cusser]

Agree with the others: 5.9 Volts at the coil is not correct, first thing I'd work on.
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1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297

[woodgoldendale]

make sure the timing light does not have an advance setting on it

[RONIN10]

Not much to add as I got distracted today by getting zapped by an exposed lead on a wire. Fixed that and fiddled with the carb some more and now I can drive it again, just need to overrev each gear moreso than normal to keep from sputtering. Tomorrow is back to the electrical business.

[RONIN10]

[ashman40]

Since you have 11.7v at the regulator, you need to start working your way to the coil + (15) connection.

BTW, I feel 11.7v is borderline. Is this the voltage you get when the engine is running and the generator is charging? You should see something like 12.8v at the regulator w/ the engine at a fast idle.

First stop should be the back of the headlight switch. Terminal #30 comes from the battery/regulator (thickest wire). You should see something close to 11.7v.

Next the #30 terminal on the ignition switch. This wire comes from the headlight switch.

Next hit the lower end of the #1 & #2 fuses (black wires). This is where the coil gets it's power from. Note the voltage here. If this is anywhere close to 11.7v, then your problem is with the wire run from here to the coil.
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AshMan40
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'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!}

[RONIN10]

[bugninva]

the values that ashman has quoted are too low...you should have a little over 12v at the battery with the engine (and key) off.... you should approach 14volts when the engine is sped up...if you don't you won't have enough voltage to charge the battery and run the electronics...anything lower than 13.5volts when the engine is over 2500-3000 rpms is too low....
check out speedy jim's site...
http://www.nls.net/mp/volks/htm/gen.htm
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[Bugorsh]

[RONIN10]