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flyboat
Samba Member
Joined: April 21, 2010
Posts: 2752
Location: Bath NC
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 Posted: Tue Jun 19, 2012 6:06 pm Post subject: Starting issues, Bad starter? UPDATE |
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When the battery is below 12.3 volts the starter will not engage. I can jump the starter with a screw driver and the battery has enough juice to start the car. OK, I need a hard start relay installed. This is no problem.
When I check the battery with a Volt meter while the car is running. I get 12.6 volts max. But when the starter is engaged it pulls the battery down very quickly. Is my problem the starter or the battery or the alternator. My guess is the starter and alternator together.
the battery is 4 months old but it is a standard battery designed for the bettle. My engine is a 2276 with 9-1 compression. What should I do?
Thanks
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Last edited by flyboat on Wed Jun 20, 2012 5:48 pm; edited 1 time in total |
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mcmscott
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Joined: March 12, 2010
Posts: 4858
Location: sanger ca
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| Posted: Tue Jun 19, 2012 6:51 pm Post subject: |
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| Check for a voltage drop between trans and battery ground first |
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MJulien
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Joined: September 04, 2005
Posts: 498
Location: West Michigan
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| Posted: Wed Jun 20, 2012 6:23 am Post subject: |
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| you should be getting at least 13+ to 14 volts when the Alt is working. Sounds like an alternator problem. |
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flyboat
Samba Member
Joined: April 21, 2010
Posts: 2752
Location: Bath NC
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| Posted: Wed Jun 20, 2012 6:39 am Post subject: |
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Yeah, that's why I think I have an alt problem. But pulling the battery down so fast makes me think I have a starter issue too. It seems the starter is drawing way too many amps. I have taken it to a shop today to check out the amp draw and alt output. The shop's equipment will also tell if I have a bad cell in the battery. When I charge the battery with a battery charger overnight, I still only get 12.6 volts
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mcmscott
Samba Member
Joined: March 12, 2010
Posts: 4858
Location: sanger ca
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| Posted: Wed Jun 20, 2012 7:17 am Post subject: |
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Are you checking at the alternator or at the battery? Not saying the alternator is not bad, just trying to help you diagnose a problem instead of assuming a problem.
If there is resistance on the ground side your battery voltage will never be as it should, also your starter will not have sufficiant voltage(explaining the jump start needed)
Load testing a fully charged battery you should not see a drop past 9.6 volts |
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Dale M.
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Joined: April 12, 2006
Posts: 20380
Location: Just a tiny bit west of Yosemite Valley
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| Posted: Wed Jun 20, 2012 7:21 am Post subject: |
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A fully charged battery only reads about 12.6 to 12.8 volts (at rest) but can be as high as 13.5 volts HOT OFF the charger, after battery has had chance to "rest " (chemically) 12.6 to 12.8 is nominal charge voltage...
Lots to be learned about batteries here...
http://www.batteryfaq.org/
A starter will draw about 200-300 amps at spin up can pull battery down to as low as 8-9 volts during starter run time...
A fully functioning alternator should push battery voltage at about 14 volt DURING CHARGE.. Do you have a functioning ALT lamp on D+ circuit of alternator?
Do you have valid ground path from battery( minus terminal (-)) to engine case ( ground cable directly to transaxle or ground strap across any rubber motor mounts that may isolate transaxle from chassis)?
If any of your battery terminals (or ground connections) look like this, "HUSTON WE HAVE A PROBLEM".....
(always like this picture because of green anti corrosion pad on battery terminal)
IF you have these type of cable repair terminals at battery ( these are your best friend in a emergency but your worst enemy over time as they promote corrosion at clamp area) ...
Replace cables with these...
And clean and use some sort of anti-corrosion "grease" on battery terminals...
Dale
_________________
“Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.
"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
============================================================
All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ... |
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flyboat
Samba Member
Joined: April 21, 2010
Posts: 2752
Location: Bath NC
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| Posted: Wed Jun 20, 2012 7:52 am Post subject: |
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| Dale M. wrote: |
A fully charged battery only reads about 12.6 to 12.8 volts (at rest) but can be as high as 13.5 volts HOT OFF the charger, after battery has had chance to "rest " (chemically) 12.6 to 12.8 is nominal charge voltage...
Lots to be learned about batteries here...
http://www.batteryfaq.org/
A starter will draw about 200-300 amps at spin up can pull battery down to as low as 8-9 volts during starter run time...
A fully functioning alternator should push battery voltage at about 14 volt DURING CHARGE.. Do you have a functioning ALT lamp on D+ circuit of alternator?
Do you have valid ground path from battery( minus terminal (-)) to engine case ( ground cable directly to transaxle or ground strap across any rubber motor mounts that may isolate transaxle from chassis)?
If any of your battery terminals (or ground connections) look like this, "HUSTON WE HAVE A PROBLEM".....
(always like this picture because of green anti corrosion pad on battery terminal)
IF you have these type of cable repair terminals at battery ( these are your best friend in a emergency but your worst enemy over time as they promote corrosion at clamp area) ...
Replace cables with these...
And clean and use some sort of anti-corrosion "grease" on battery terminals...
Dale |
I have a good ground path, new ground strap. I have a functioning Alt lamp. I did read where someone was having intermittant charging problems and found the Alt lamp had too much resistance, 9 ohm as opposed to 4 ohms. I have not checked that yet. The light does go out after the engine starts but the volt reading at the battery when the engine runs is 12.5 or so, not 13+ volts.
I have the correct battery cables as well. It all new so it looks good and fresh.
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Porsche 914
09 Z06 Vette track car |
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Dale M.
Samba Member
Joined: April 12, 2006
Posts: 20380
Location: Just a tiny bit west of Yosemite Valley
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| Posted: Wed Jun 20, 2012 8:04 am Post subject: |
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Alternator lamp resistance should not be critical.... Only function of alt lamp is to give alternator a shot of 12 volts to excite it at initial spin up, once "excited" only thing lamp does is indicate alternator output ( by going off) ....
Theory is there is ground standing on D+ terminal with engine not running but key on and +12 volts on "other" side of lamp... There is current flow, lamp lights (no "charge" condition).... Once the alternator is "excited" (spinning with initial shot of 12 volts through lamp) the ground at D+ terminal transitions to 12 volts (follows B+ output) and as voltage comes up on D+ terminal it matches voltage on "other side" of lamp, as voltage equalizes across lamp, current stops flowing and lamp goes out.... Lamp going out should indicate alternator is working.... Why its not putting out at about 14 volts could mean you have internal regulation issue with alternator or some external wiring problem (bad connection) ...
http://www.mydune-buggy.com/dl_files/AlternatorBasics.pdf
Dale
_________________
“Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.
"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
============================================================
All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ... |
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flyboat
Samba Member
Joined: April 21, 2010
Posts: 2752
Location: Bath NC
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| Posted: Wed Jun 20, 2012 8:13 am Post subject: |
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Ok, good to know. The car is in the hands of long time friend and well respected VW mechanic. I will post his findings later today.
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flyboat
Samba Member
Joined: April 21, 2010
Posts: 2752
Location: Bath NC
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| Posted: Wed Jun 20, 2012 5:47 pm Post subject: |
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Update:
The problem is a faulty alternator. It makes 12 volts but only 2-3 amps. Apparently, that's enough to make the dash light go out. The battery is good and thestarter is drawing the correct amps under load.
As it turns out, my shop battery charger is not working properly. That is why I was having a hard time trouble shooting the problem.
Anyway, it's all good now. I'll put the new alternator on tomorrow.
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Porsche 914
09 Z06 Vette track car |
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Dale M.
Samba Member
Joined: April 12, 2006
Posts: 20380
Location: Just a tiny bit west of Yosemite Valley
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| Posted: Wed Jun 20, 2012 7:38 pm Post subject: |
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| flyboat wrote: |
Update:
The problem is a faulty alternator. It makes 12 volts but only 2-3 amps. Apparently, that's enough to make the dash light go out. The battery is good and the starter is drawing the correct amps under load.
As it turns out, my shop battery charger is not working properly. That is why I was having a hard time trouble shooting the problem.
Anyway, it's all good now. I'll put the new alternator on tomorrow. |
Nothing like a double whammie to mess with your mind.....
Dale
_________________
“Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.
"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
============================================================
All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ... |
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flyboat
Samba Member
Joined: April 21, 2010
Posts: 2752
Location: Bath NC
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| Posted: Thu Jun 21, 2012 7:08 am Post subject: |
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Yep, Thanks guys.
Roger
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