Return of bucking. A jinx and a curse? Solved!

[dingo]

with a cheap multimeter, a simple volt Drop test on both pos and neg sides of systems can reveal hidden failures...

[luftvagon]

Funny story regarding the ground on my Vanagon. Previous owner used a long bolt and 100 washers to create a body to ground mounting point...

[56ovalbug]

Glad the problem is solved and it was an easy inexpensive fix. Don't feel bad - If the connection looked good why suspect it to be bad... especially since you checked to make sure it was tight. I wouldn't expect it to cause the bucking though. Years ago, on my '75 Westy, when my transmission to chassis ground broke the starter would barely turn the engine over but once I got it started the bus ran fine. Live & learn.

[aopisa]

It may have been a combination of re-cleaning the FI grounds on the back of the plenum, the new section of TS ll wire and the improved grounding of the battery ground cable.

That's the thing about this type of problem. I will never know. You here a clunking coming from the rear of the bus. Replace the CV joint and the clunking stops. Problem identified, problem solved. As I stated before, I cannot really recall seeing a bucking problem have exactly the same cause and solution. They all seem to be unique. And when it is a problem that comes and goes, it makes knowing for sure even more of a guessing game. I do know we went from horrible running to full power and no bucking in a matter of minutes that night. So, I am reasonably sure that we may have corrected the issue.

I drove it for a total of about 70 trouble free miles this weekend. After going through so many things that did not make a difference, I am still in a state of denial that I can actually drive it again. At any rate, I put the toolbox back under the bench seat and hopefully it will stay there for a little while.

Many thanks to everyone who offered help while I slogged through this issue.

Now onto the dimly glowing alternator light....

[Randy in Maine]

Continue on with your electrical connectiions at the alternator and the voltage regulator using your volt ohm meter. The more you use it the more comfortable you will be with it. One of the most handy items anyone has in their bag of tricks.

Also have a look at the fuse box and notably at that 8 amp fuse #12 including the connection going toward it.

Also if you have not downloaded the electrical schematic for your bus using the diagram at Vintage Bus and taken it to a print shiop for printing and laminating on a 11x17" sheet, you are missing a helpful reference.

If there is a HVAC supply shop or Radio Shack near you, invest in some "De-Oxit" for exposed electical connection and coat all of those that you just cleaned with it.

[aopisa]

Continue on with your electrical connectiions at the alternator and the voltage regulator using your volt ohm meter. The more you use it the more comfortable you will be with it. One of the most handy items anyone has in their bag of tricks.

Also have a look at the fuse box and notably at that 8 amp fuse #12 including the connection going toward it.

Also if you have not downloaded the electrical schematic for your bus using the diagram at Vintage Bus and taken it to a print shiop for printing and laminating on a 11x17" sheet, you are missing a helpful reference.

If there is a HVAC supply shop or Radio Shack near you, invest in some "De-Oxit" for exposed electical connection and coat all of those that you just cleaned with it.

Yes, I need to recheck the VR connections more thoroughly. Are the alternator connections easily accessible? It looks like there are about 6 steps of removing the belt and tins before you get to the wiring harness.

I purchased some De-Oxit a few weeks ago and have been using it on all of the electrical connections that I have checked and cleaned.

[Randy in Maine]

It is not bad getting in there to do the alternator and VR connections in your own driveway.

It is worse laying in nose deep cold mud and light snow in North Dakota in November.

[56ovalbug]

My '74 has a dimly glowing alternator light - you can only see when it's dark. I've tried everything... new alternator, different alternator wiring harness , different instrument cluster, cleaned connection, fuses... nothing fixed it. It's been like that for 18 years now.

[aopisa]

My '74 has a dimly glowing alternator light - you can only see when it's dark. I've tried everything... new alternator, different alternator wiring harness , different instrument cluster, cleaned connection, fuses... nothing fixed it. It's been like that for 18 years now.

Even different alternators, huh? I know many people live with the dim glowing light. This is a new issue for my bus. It is visible in daylight. If I had to guess I would say the bulb glows at about 20-25% of full brightness. I know the alternator is charging the battery. I will go through the checklist, but guess I won't sweat it too much at this point.

I am just glad to have a running bus.

[dingo]

dimly glowing light...usually indicates a bad diode in the pack. Set your meter to AC and test for ripple

[aopisa]

dimly glowing light...usually indicates a bad diode in the pack. Set your meter to AC and test for ripple

I am really lacking in electrical knowledge. Could you please explain this procedure a little more. What does having a bad diode mean? I assume that would require an alternator replacement.

[airkooledchris]

Now onto the dimly glowing alternator light....

just ignore it. mine has done that since day one, and I (for lack of more important problems to address, at that time) tried like hell to track it down. swapped/replaced all sorts of bits and pieces and while it got moderately better - it never went away.

now I think of it as a light letting me know my alternator is working, and so well that it gives me a tiny bit extra for this bulb to run all the time. it's even better than stock!

[aopisa]

Now onto the dimly glowing alternator light....

just ignore it. mine has done that since day one, and I (for lack of more important problems to address, at that time) tried like hell to track it down. swapped/replaced all sorts of bits and pieces and while it got moderately better - it never went away.

now I think of it as a light letting me know my alternator is working, and so well that it gives me a tiny bit extra for this bulb to run all the time. it's even better than stock!

Great! I will apply that same theory when the oil light comes on!

[Randy in Maine]

Do this....

With volt meter in hand, test the voltage before you start the bus. Note that voltage.

Start the bus and rev to about 2000 RPMs and note the voltage.

Drive it a while (like to Chicago for a pizza) and note the voltage. Drive it back to Vermont and note the voltage.

See if anything really changes. If nothing does, don't worry about it. Just drive it

[aopisa]

Do this....

With volt meter in hand, test the voltage before you start the bus. Note that voltage.

Start the bus and rev to about 2000 RPMs and note the voltage.

Drive it a while (like to Chicago for a pizza) and note the voltage. Drive it back to Vermont and note the voltage.

See if anything really changes. If nothing does, don't worry about it. Just drive it

Here is what I have found so far.

Engine off = 12.77
Engine on = jumps to about 15.1
Engine at approx. 2,000 RPM = 14.9
Engine idling with Hi beams & radio on = 12.8
Hi beams & radio at approx. 2,000 RPM = 13.6

I have not yet left for Pizza in Chicago. Perhaps lobster in Maine, I here there is a glut? I am heading out now for a drive so I will recheck.

I have a new voltage regulator so I will also repeat with it plugged in.