XJ6 & XJ12 Series I, II & III 1968-1992

GM 94amp Alternator

 
  #1  
Old 07-10-2019, 07:02 AM
yachtmanbuttson's Avatar
Senior Member
Thread Starter
Join Date: Jun 2016
Location: Palm City, Florida
Posts: 597
Received 75 Likes on 52 Posts
Default GM 94amp Alternator

I bought a 94amp alternator from John's Cars a while back and it's performed flawlessly charging at 13v up until yesterday. It's now jumped up to 18v at anything above idle. It drops back to 13v at idle. Anybody have any ideas? The battery is about 3years old.
 
  #2  
Old 07-10-2019, 07:07 AM
Veteran Member
Join Date: Mar 2008
Location: Pacific Northwest USA
Posts: 20,148
Received 6,550 Likes on 4,861 Posts
Default

I don't see how it can be anything except a voltage regulator failing

But I'm just two sips into my first cuppa coffee

Cheers
DD
 
  #3  
Old 07-10-2019, 07:14 AM
yachtmanbuttson's Avatar
Senior Member
Thread Starter
Join Date: Jun 2016
Location: Palm City, Florida
Posts: 597
Received 75 Likes on 52 Posts
Default

And that's onboard the alternator itself - right?
 
  #4  
Old 07-10-2019, 07:29 AM
Senior Member
Join Date: Sep 2017
Location: Lincoln Ontario
Posts: 267
Received 52 Likes on 35 Posts
Default

Bill,
How did you mount that GM unit and how does it interact with the XJ6 wiring/idiot light etc.
 
  #5  
Old 07-10-2019, 07:49 AM
yachtmanbuttson's Avatar
Senior Member
Thread Starter
Join Date: Jun 2016
Location: Palm City, Florida
Posts: 597
Received 75 Likes on 52 Posts
Default

It was a direct bolt in relaxing the Lucas with same wiring
 
  #6  
Old 07-10-2019, 10:01 AM
yachtmanbuttson's Avatar
Senior Member
Thread Starter
Join Date: Jun 2016
Location: Palm City, Florida
Posts: 597
Received 75 Likes on 52 Posts
Default

Just re-read the below chat about "Ignition Light Remains On". And Jeff even talks about 18v if the battery is going bad. MAYBE that's my problem!!!??? The date code is 2/16 and it does get pretty hot here in Florida.
 
  #7  
Old 07-10-2019, 11:11 AM
Veteran Member
Join Date: Jul 2012
Location: Walnut Creek, California
Posts: 5,732
Received 1,945 Likes on 1,569 Posts
Default

I do not see the connection between excess alternator out put and a failing battery???

but, I sure understand the word "electrickery" ! I did not coin the word, but admit to popularizing it!

So:

1. Swap in another battery and see if the 18v continues?
2. Check the battery. :Include a load test.
3. Warranty on the alternator?

Gee, Doug, I'm rationed to one cup of coffee....

Carl
 
  #8  
Old 07-10-2019, 12:41 PM
yachtmanbuttson's Avatar
Senior Member
Thread Starter
Join Date: Jun 2016
Location: Palm City, Florida
Posts: 597
Received 75 Likes on 52 Posts
Default

Yup, you're right, not the battery. Still getting 18v with a new swapped in battery. I guess that leaves the voltage regulator as the culprit?
 
  #9  
Old 07-11-2019, 01:25 PM
Senior Member
Join Date: Aug 2017
Location: Cincinnati Ohio
Posts: 412
Likes: 0
Received 226 Likes on 114 Posts
Default

Bill, I would get that taken care of right away. We were at a car show and a guy with a modified 57 Chevy that had the battery in the trunk told me that his alternator went crazy and the battery either boiled over or exploded, I can't remember which. The result was battery acid all over his pristine trunk.
 
  #10  
Old 07-11-2019, 02:35 PM
yachtmanbuttson's Avatar
Senior Member
Thread Starter
Join Date: Jun 2016
Location: Palm City, Florida
Posts: 597
Received 75 Likes on 52 Posts
Default

Thanks Jeff. I already parked it and ordered a rebuild kit. Only bad things can happen with 18v!
 
  #11  
Old 07-12-2019, 02:07 PM
yachtmanbuttson's Avatar
Senior Member
Thread Starter
Join Date: Jun 2016
Location: Palm City, Florida
Posts: 597
Received 75 Likes on 52 Posts
Default

Sometimes it's pretty obvious why something is wrong. This seems to be one of those times. Note one of the brushes is broken and the capacitor is detached from its wire and the housing burned. Glad I have a complete rebuild kit on order.
 
  #12  
Old 07-13-2019, 07:28 AM
yachtmanbuttson's Avatar
Senior Member
Thread Starter
Join Date: Jun 2016
Location: Palm City, Florida
Posts: 597
Received 75 Likes on 52 Posts
Default

Emailed Johns Cars with the above picture and he is sending me a new one with an apology! Now that's what I call SERVICE. I'll keep you posted.
 
  #13  
Old 07-13-2019, 09:42 AM
Veteran Member
Join Date: Jul 2012
Location: Walnut Creek, California
Posts: 5,732
Received 1,945 Likes on 1,569 Posts
Default

!. Some folks criticize John and his business plan. I am not one of them. I was always well treated. this is what I would have expected. The best advertising one can get in business. Stand by the product.

2. As I recall, John sells a part that adapts to the IL 6 to enable the Delco to bolt in. Hence, your comment as to a direct bolt in. I do recall a fellow on another forum doing so by subbing in the Delco for the air pump!

3. Somewhere or another, I have ajar of Delco alternator fix parts. I fixed one for my V* roadster.A deviation from it's all 40's theme. A frame, Flat head v8. T body and 35 Ford wire wheels... Oh, and a 32 B grill....
 
  #14  
Old 07-13-2019, 01:54 PM
Senior Member
Join Date: Aug 2017
Location: Cincinnati Ohio
Posts: 412
Likes: 0
Received 226 Likes on 114 Posts
Default

Carl, I sure hope you can share a photo with us of your T - A - deuce - flatty!
 
  #15  
Old 07-13-2019, 02:13 PM
Veteran Member
Join Date: Jul 2012
Location: Walnut Creek, California
Posts: 5,732
Received 1,945 Likes on 1,569 Posts
Default

One of the ones I let go that I wish I had not!!! and no surviving pictures either, oh woe is me..

Carl
 
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
DevilK9
XJ6 & XJ12 Series I, II & III
7
12-06-2008 07:48 PM
lrizzell
XJ XJ8 / XJR ( X308 )
0
08-05-2008 05:52 PM
milkchug
X-Type ( X400 )
11
12-16-2007 09:38 AM
X-Type ( X400 )
10
03-21-2007 10:59 PM

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 

Thread Tools
Search this Thread
Quick Reply: GM 94amp Alternator


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: