| Author |
Message |
Tim Donahoe
Samba Member
Joined: December 08, 2012
Posts: 11740
Location: Redding, CA
|
 Posted: Wed Sep 13, 2017 8:41 pm Post subject: Re: Glowing alternator light tonight! Fixed!!! |
 |
|
Allen, I may take you up on the harness thing if I find the voltage drop in the 9mm wire from the B+battery post to the Ta connector.
I was not testing in parallel previously, but will play with it tomorrow--after I sort out the new oil leak.
And Jimbo, from what I've read, that tenth of a volt is five times the limit. Although, that's from a several sources I've read on the web  .
.01 to.02 was listed as passable. Over that, and there is some resistance--a connection, whatever. So, I'm going to to a proper voltage drop test to pin it down.
Tim
_________________
Let's do the Time Warp again!
Richard O'Brien |
|
| Back to top |
|
 |
rockerarm
Samba Member
Joined: December 16, 2009
Posts: 3552
Location: Los Angeles
|
|
| Back to top |
|
|
VW_Jimbo 
Samba Member
Joined: May 22, 2016
Posts: 9966
Location: Huntington Beach, CA
|
| Posted: Wed Sep 13, 2017 8:57 pm Post subject: Re: Glowing alternator light tonight! Fixed!!! |
|
|
| Tim Donahoe wrote: |
| Jimbo, from what I've read, that tenth of a volt is five times the limit. Although, that's from a several sources I've read on the web. Tim |
I agree in regards to modern, current cars. But when you go down a few decades, the voltage drop increases, both actually and in its value.
My experience has been these cars can withstand up to, a full volt being dropped with little to no ramifications, maybe even two volts!
The flip is I had a 1998 Toyota Camry that dropped .4 volts on an injector wire. Made that car run like crap and took me on a few hour tour of the electrical wire harness, around 80 wires, tested one at a time!
_________________
Jimbo
There is never enough time to do it right the first time, but all the time necessary the second time!
| TDCTDI wrote: |
| Basically, a whole bunch of fuckery to achieve a look. |
| 67rustavenger wrote: |
GFY's Xevin and VW_Jimbo!  |
|
|
| Back to top |
|
|
Tim Donahoe
Samba Member
Joined: December 08, 2012
Posts: 11740
Location: Redding, CA
|
| Posted: Wed Sep 13, 2017 9:37 pm Post subject: Re: Glowing alternator light tonight! Fixed!!! |
|
|
So, if I only have .10 volt difference (one tenth of a volt, if I'm reading the multimeter properly), then it's well within a tolerable loss. And a lower reading at the battery when all accessories are switched on is normal. Correct?
By the way, how do you guys hook up your multimeter to the B+ post on the alternator, then also hook up to the wire coming from the B+ post that is located--and connected to Ta) under the back seat? My wires on my multimeter don't stretch that far. I can only assume that you can use a jumper wire from the B+ post and route it around to where you can tap into it in the cabin. Correct?
Sorry for the questions on this issue, but all the videos I've seen and all the printed, always show, or tell, of the mechanic working on a car where all these connections are located within close proximity of all parts involved, and they're all under the hood.
Tim
_________________
Let's do the Time Warp again!
Richard O'Brien |
|
| Back to top |
|
|
Frodge
Samba Member
Joined: October 04, 2006
Posts: 1991
Location: Dump
|
| Posted: Thu Sep 14, 2017 2:07 am Post subject: Re: Glowing alternator light tonight! Fixed!!! |
|
|
| FYI, I use the Wolfsburg West silicone drain gasket and they really work great. Have had the same gasket set on for 10 years or so. The valve covers I have are cork, I've not tried the silicone ones yet. |
|
| Back to top |
|
|
rockerarm
Samba Member
Joined: December 16, 2009
Posts: 3552
Location: Los Angeles
|
| Posted: Thu Sep 14, 2017 7:37 am Post subject: Re: Glowing alternator light tonight! Fixed!!! |
|
|
| VW_Jimbo wrote: |
| Tim Donahoe wrote: |
| Jimbo, from what I've read, that tenth of a volt is five times the limit. Although, that's from a several sources I've read on the web. Tim |
My experience has been these cars can withstand up to, a full volt being dropped with little to no ramifications, maybe even two volts!
|
Hi. I certainly hope Jimbo sees this and corrects himself. An up to two volt drop is extreme.
If you had a 2v drop from the alt to the battery (14.4 - 2.0 = 12.2v) you'd be in worse shape than when you started. This same voltage drop may not even engage the starter and will also result in inefficient headlights.
Yes Tim, most techs will have sets of jumper wires to facilitate these tests. You can even buy some test leads that use the alligator clip on one end and the banana style end to insert into the DVOM. I made a couple of long test leads specifically for this.
The entire VW component layout is unique in comparison to many front engine veh's. Their components may be only 2-3 feet from each other whereas ours have the components (batt, starter, alt, fuse box, switches) up to 8 feet away from each other. On cars with over 40 years of use this could be a huge contributor to voltage drops. |
|
| Back to top |
|
|
VW_Jimbo
Samba Member
Joined: May 22, 2016
Posts: 9966
Location: Huntington Beach, CA
|
| Posted: Fri Sep 15, 2017 7:45 am Post subject: Re: Glowing alternator light tonight! Fixed!!! |
|
|
Thank you for the opportunity to expand on my thought. I have reread what I wrote and can see where my train of thoughts did not convey 100%. I am no English major, that is the wife. I am hands on, pictures would be my first choice in communicating. Words are second.
[quote="rockerarm"]
| VW_Jimbo wrote: |
My experience has been these cars can withstand up to, a full volt being dropped with little to no ramifications, maybe even two volts!
|
I have witnessed a full volt dropping on hundreds of these cars in the charging system circuit. Yes, they did start and run but when under heavy electrical loads, the owners would complain about dim headlights. That was always the first complaint from them. The second complaint was a "no crank" condition or a "slow crank" condition. All voltage drop related. Those no crank or slow crank was typically at the battery terminals and almost always due to a lack of maintenance (Cleaning the terminals).
| Quote: |
| Hi. I certainly hope Jimbo sees this and corrects himself. An up to two volt drop is extreme. |
Yes, a two volt drop is extreme, but still will allow the car to function. The two volt drop was typically found on the coil wire, after being melted along its run. Some of those cars where still running, albeit not great, but they did come in on there own power, and they cranked just fine. The work order would say something like, "cranks but has a hard time starting - please advise". I would spend an hour or so checking wires, measuring voltages and looking for readings out of the normal parameters. My go to test, was a voltage drop test! What did I find on lighting circuits, ignition circuits, wiper circuits and horn circuits, a drop of a volt or two. Most times, it was around .8 volts. That seemed like the magic point.
| Quote: |
| Yes Tim, most techs will have sets of jumper wires to facilitate these tests. You can even buy some test leads that use the alligator clip on one end and the banana style end to insert into the DVOM. I made a couple of long test leads specifically for this. |
The leads I had were from Fluke and had interchangeable ends, I could use all sorts of clips and points. Sometimes I would take a straight pen, like for sewing, and push it into the terminal or wire, to measure voltage. The leads also could be connected in series with a connector found online. It did drop a little voltage, but the Fluke 88 had a "zero" function that would compensate for that drop in the measurement.
| Quote: |
| The entire VW component layout is unique in comparison to many front engine veh's. Their components may be only 2-3 feet from each other whereas ours have the components (batt, starter, alt, fuse box, switches) up to 8 feet away from each other. On cars with over 40 years of use this could be a huge contributor to voltage drops. |
Yes, the age of the wiring is a huge variable that has to be considered. Years of life in any environment will cause degradation and impact readings. One must understand the impact of environment on the systems. Down here at the beach, high salty moisture, all year round, causes all sorts of stuff to corrode! I am continuously replacing house flashing and waterproofing components due to corrosion. Same goes for cars! I will attest to the fact that working for 40 years can lead to degradation in strength, flexibility and speed!
_________________
Jimbo
There is never enough time to do it right the first time, but all the time necessary the second time!
| TDCTDI wrote: |
| Basically, a whole bunch of fuckery to achieve a look. |
| 67rustavenger wrote: |
| GFY's Xevin and VW_Jimbo! |
|
|
| Back to top |
|
|
|
