Dennis
Would the grounding you are suggesting also be advised for an 88 WBX 2.2 engine?

Dennis Jowell
Scotch Hollow Farm
Newbury, Vermont 

> On Sep 13, 2016, at 6:19 PM, Dennis Haynes <d23haynes57@HOTMAIL.COM> wrote:
> 
> I would start by looking at the ground strap itself. Also, you may be getting miss lead so you also need to look at the B+ wire from the alternator to the battery. It is common for the this wire to see a significant voltage drop to being somewhat undersized and after all these years the conductors are going bad. 
> 
> Losing voltage with the system under load is normal. .5 volt just across the ground strap is high for just headlights and running load. Try replacing that ground with a 2 gauge wire.  Also consider another ground at the alternator. I would suggest a 6 gauge for that one. 
> 
> Dennis
> 
> 
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Christophe Guilbert
> Sent: Monday, September 12, 2016 1:08 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Engine Ground voltage drop under load, please help diagnose.
> 
> I have a vanagon 1983 air-cool CA.
> 
> I would really appreciate some help to diagnose my problem , even my mechanic does not understand it.
> 
> Here is the story:
> 
> My battery is new and read 12.6v . I have a new alternator which deliver 14V
> 
> When the van idle I read 13.71V at the battery terminal. When I start lights and fan blower , I read 13.24V.
> 
> I tried to check if I had any leak between the battery terminal and the alternator under load (lights and fan blower):
> 
> For terminal + , I have none , well something like -0.1V
> 
> For terminal - , not only I have -0.5V at the alternator level but also to any ground point of the engine,  which is way too much ! ( I have -0.1V only if I am not under load)
> 
> In order to remind how the engine is grounded , here is the pathway , from battery to the body using a ground strap , than from body to transmission front  mounting using a ground strap, than from transmission front mounting to the transmission via metal contact and/or
> 3 bolts and stud. than from transmission to the whole engine.
> 
> Trying to understand where my 0.5v drops come from , I checked if I had any voltage drop between the battery ground terminal and the ground strap terminal bolted to the transmission front mounting . I have none
> (-0.04v) .  So voltage drop must happened between the transmission front mounting and the transmission or the engine.  I plugged my voltmeter between  the ground strap terminal going to the transmission front mounting and the engine (any points) and I found -0.45V.
> 
> When I plugged my voltmeter  between  the ground strap terminal going to the transmission front mounting bolt and one of the transmission bolt (after making it bare metal), I got -0.35V. So the main culprit seems to be the connection between the transmission front mounting and the transmission itself. I removed the transmission front mounting , clean bolts ,studs, washers, any point of contacts, I make them bare metal, used deoxit D5 and di-electric grease before putting every back. I retest the ground voltage between the battery and the engine and I got -0.4V (instead of -0.5V) under load.
> 
> From this point I don't know what to do and would appreciate any explanation and advices.
> 
> I am thinking to reground the engine . If I quickly used a  jump start cable to reground the engine , I reduce my voltage drop from -0.4V to -0.2V. I guess I can do better with  a proper dedicated ground cable .
> 
> I would rather avoid  that option thought because I would like to fully understand what's going on first.
> 
> Any though.
> 
> Thanks for any help.
> 
> Chris