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RONIN10 Samba Member
Joined: April 30, 2007 Posts: 594 Location: Seattle, WA
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Posted: Fri Dec 07, 2007 3:37 pm Post subject: Electrical Anomoly |
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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! _________________ Andrew
Oscar: 1976 Westfalia Deluxe Camper, 2.0L FI, Manual Transaxle |
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splitty_smile Samba Member
Joined: October 01, 2003 Posts: 506 Location: Independence, OR
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Posted: Fri Dec 07, 2007 3:42 pm Post subject: |
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What is your voltage at the coil? _________________ ---1976 standard bus "The Red Toad" transplanted 78 FI 2.0, Hydraulic lifters
---1974 Super Beetle "Gus" 1835 Engle 110 Dual Kadrons |
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RONIN10 Samba Member
Joined: April 30, 2007 Posts: 594 Location: Seattle, WA
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Posted: Fri Dec 07, 2007 3:57 pm Post subject: |
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splitty_smile wrote: |
What is your voltage at the coil? |
Just ran out and checked it. It's 5.9V at the coil and just because it seemed like the right thing to do while I was out there, 12.5 V across the battery. _________________ Andrew
Oscar: 1976 Westfalia Deluxe Camper, 2.0L FI, Manual Transaxle |
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DrDarby Samba Member
Joined: May 12, 2004 Posts: 6534 Location: Northern Illinois
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Posted: Fri Dec 07, 2007 3:59 pm Post subject: |
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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. _________________ Midwest Autosavers, Inc. Woodstock, IL |
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RONIN10 Samba Member
Joined: April 30, 2007 Posts: 594 Location: Seattle, WA
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Posted: Fri Dec 07, 2007 4:26 pm Post subject: |
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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. _________________ Andrew
Oscar: 1976 Westfalia Deluxe Camper, 2.0L FI, Manual Transaxle |
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bugninva Samba Member
Joined: December 14, 2004 Posts: 8858 Location: sound it out.
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Posted: Fri Dec 07, 2007 4:48 pm Post subject: |
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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.. _________________
[email protected] wrote: |
With a show of hands, who has built over 1000 engines in the last 25 years? Anyone? |
GEX has. Just sayin |
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RONIN10 Samba Member
Joined: April 30, 2007 Posts: 594 Location: Seattle, WA
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Posted: Fri Dec 07, 2007 7:31 pm Post subject: |
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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. _________________ Andrew
Oscar: 1976 Westfalia Deluxe Camper, 2.0L FI, Manual Transaxle |
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Bashr52 Samba Member
Joined: July 16, 2006 Posts: 5666 Location: On an island in VA
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Posted: Fri Dec 07, 2007 8:40 pm Post subject: |
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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! |
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Calex59 Samba Member
Joined: October 17, 2007 Posts: 64 Location: Ione, California
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Posted: Fri Dec 07, 2007 11:06 pm Post subject: |
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RONIN10 wrote: |
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. |
Check your voltage at the regulator. If you have 12 + at the battery and 5.9 at the positive side of the coil(not the center wire) then you have a problem between the battery and the coil. Your coil is most likely good. Check the regulator, if your getting the correct voltage there, keep checking all your wiring until you find the bad spot. |
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Mr. Loaf Samba Member
Joined: March 30, 2005 Posts: 2098 Location: Okra, Oklahoma
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Posted: Sat Dec 08, 2007 6:00 am Post subject: |
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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. _________________ Never drive faster than your Angel can fly
$24,100 was too hard to resist................. |
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RONIN10 Samba Member
Joined: April 30, 2007 Posts: 594 Location: Seattle, WA
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Posted: Sat Dec 08, 2007 2:10 pm Post subject: |
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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. _________________ Andrew
Oscar: 1976 Westfalia Deluxe Camper, 2.0L FI, Manual Transaxle |
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Cusser Samba Member
Joined: October 02, 2006 Posts: 31360 Location: Hot Arizona
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woodgoldendale Samba Member
Joined: May 10, 2006 Posts: 76 Location: Goldendale, Wa
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Posted: Sat Dec 08, 2007 5:55 pm Post subject: |
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make sure the timing light does not have an advance setting on it |
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RONIN10 Samba Member
Joined: April 30, 2007 Posts: 594 Location: Seattle, WA
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Posted: Sat Dec 08, 2007 6:23 pm Post subject: |
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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.
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make sure the timing light does not have an advance setting on it |
My timing light doesn't have an advace so I'm good there. Off to study a wiring diagram. _________________ Andrew
Oscar: 1976 Westfalia Deluxe Camper, 2.0L FI, Manual Transaxle |
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RONIN10 Samba Member
Joined: April 30, 2007 Posts: 594 Location: Seattle, WA
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Posted: Sun Dec 09, 2007 12:25 pm Post subject: |
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Mr. Loaf wrote: |
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. |
Did the test you described and got 0.5 Ohms. I checked the internal resistance of my multimeter (touched the leads together) and this gave me 0.3 Ohms meaning their is an additional 0.2 Ohms of resistance floating around somewhere in the circuit. This seems awfully small to suggest a short (and not an open circuit as my multimeter displays infinite resistance as the number one on the LHS of the display) which makes me think that wiring is likely good. But if this is true, why can't I get the lamp to illuminate when I disconnect the wire at the sender, ground it, then turn the ignition key? And the lamp did illuminate prior to me straightening out the wiring in the fuse box. Is it possible that the lamp socket housing in the speedometer somehow lost its grounding to the other socket housings? Those housing were stuck in there pretty good when I did the wiring correction. Is my logic just incorrect?
Incidentally, I did double check the wires into and out of the fuse box to make sure everything was still correctly connected. It is. _________________ Andrew
Oscar: 1976 Westfalia Deluxe Camper, 2.0L FI, Manual Transaxle |
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ashman40 Samba Member
Joined: February 16, 2007 Posts: 15982 Location: North Florida, USA
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Posted: Mon Dec 10, 2007 8:27 am Post subject: |
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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. _________________ AshMan40
---------------------------
'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!} |
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RONIN10 Samba Member
Joined: April 30, 2007 Posts: 594 Location: Seattle, WA
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Posted: Mon Dec 10, 2007 8:54 am Post subject: |
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ashman40 wrote: |
BTW, I feel 11.7v is borderline. Is this the voltage you get when the engine is running and the generator is charging?
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No, sorry. This was my voltage with the key on and the engine not running. By means of further information, I checked my oil pressure switch for continuity and it showed as an open circuit so I went ahead and invested $30 to replace that along with my coil. The oil light is lighting again and the coil is seeing the same 11.7 V as the regulator (tested as I described here).
Quote: |
You should see something like 12.8v at the regulator w/ the engine at a fast idle. |
I'll double check the regulator and coil to insure this is what I'm getting while running at fast idle, but I've got a busy schedule the next 48 hours so I may not get to it too soon.
Thanks for the help! I've yet to repeat my initial test w/the timing light that started this whole discovery process so I'll have to give that a go in my next work session. _________________ Andrew
Oscar: 1976 Westfalia Deluxe Camper, 2.0L FI, Manual Transaxle |
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bugninva Samba Member
Joined: December 14, 2004 Posts: 8858 Location: sound it out.
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Posted: Mon Dec 10, 2007 6:07 pm Post subject: |
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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 _________________
[email protected] wrote: |
With a show of hands, who has built over 1000 engines in the last 25 years? Anyone? |
GEX has. Just sayin |
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Bugorsh Samba Member
Joined: May 28, 2004 Posts: 1358 Location: SoCal
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Posted: Mon Dec 10, 2007 10:05 pm Post subject: Re: Electrical Anomoly |
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RONIN10 wrote: |
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 sounds like you are connecting the positive clip of your strobe to the wrong terminal on the coil and when you pull the trigger it is grounding out the coil and causing the engine to die out. Try connecting it on the other coil terminal next time you use it. _________________ In pursuit of superior handling!
SuperBeetlesOnly.com
VeeDub Parts Unlimited
Topline Parts |
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RONIN10 Samba Member
Joined: April 30, 2007 Posts: 594 Location: Seattle, WA
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Posted: Mon Dec 10, 2007 10:55 pm Post subject: Re: Electrical Anomoly |
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Bugorsh wrote: |
It sounds like you are connecting the positive clip of your strobe to the wrong terminal on the coil and when you pull the trigger it is grounding out the coil and causing the engine to die out. Try connecting it on the other coil terminal next time you use it. |
That occured to me as well as the most obvious solution as the symptoms seems to be textbook counter current issues, but I was reasonably sure I had it right when I did it...connected positive clamp on the gun to terminal 15, not terminal 1. Of course, the fog of time and some self doubt has crept in, I suppose I may have done it wrong being focused on my carb adjustment issues at the time.
Thanks for the feedback. _________________ Andrew
Oscar: 1976 Westfalia Deluxe Camper, 2.0L FI, Manual Transaxle |
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