Two Guys Garage Forum  

Go Back   Two Guys Garage Forum > Your Own Projects

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 09-20-2002, 06:43 PM
miatasc miatasc is offline
Registered User
 
Join Date: Sep 2002
Location: Louisiana
Posts: 3
miatasc is on a distinguished road
Alternater running 18 volt output

The alternater in my 99 miata is putting out 18 volts. The problem started when I installed the supercharger. Non of the install was alternater related. Installed a new alternater and still having the same problem. HELP!
Reply With Quote
  #2  
Old 09-20-2002, 07:23 PM
rapideo rapideo is offline
Registered User
 
Join Date: May 2002
Location: austin
Posts: 399
rapideo is on a distinguished road
Do you have a seperate regulator? It worked for me to clean the contacs on the plugin. Had a serious overcharge on an 84 Dodge
that the speciality shop experts couldnt fix, just parts changers,like your alternater change didnt help,it didnt help for me either. Spent a lot of money on those dummys, and the fix was free. If your reg is built into the alt then none of this will help
Reply With Quote
  #3  
Old 09-21-2002, 12:00 AM
supernova
Guest
 
Posts: n/a
you will have to change the alternater it is over charging and it will blow up your battery, trust me. change the alternater
Reply With Quote
  #4  
Old 09-21-2002, 12:20 AM
danny danny is offline
chevy enthusiast
 
Join Date: Nov 2001
Location: oklahoma
Posts: 10,975
danny is on a distinguished road
how did you determine that your alternator is putting out 18 volts? sometimes stock gauges can be incorrect.
__________________
'94 chev suburban
'99 chev k2500
if you feel that you must burn my flag please do me a favor and wrap yourself in it first
when you drive a ford you need a whole set of good wrenches-lol-
jack bauer for president
Reply With Quote
  #5  
Old 09-21-2002, 12:49 PM
rapideo rapideo is offline
Registered User
 
Join Date: May 2002
Location: austin
Posts: 399
rapideo is on a distinguished road
Any alternator is capable of 18 volt output. They have to be controled. Thats the job of the regulator. If the guage is'nt right, a boiling battery is a sign. That 99 Mazda likely has the regulater in the alternator. He already changed the alt, so the problem is elsewhere.
Reply With Quote
  #6  
Old 09-21-2002, 10:01 PM
justen's Avatar
justen justen is offline
Diesel Nut
 
Join Date: Dec 2001
Location: Minnesota
Posts: 4,306
justen is on a distinguished road
If you don't have a alternator tester bring it into a auto parts store alot of them can hook it up and run the alternator and tell you what the true output is, Ya never know. Gauges can go anytime especailly when you add something new.
__________________
Real trucks don't have spark plugs!
Reply With Quote
  #7  
Old 09-22-2002, 03:23 PM
Durango Durango is offline
Registered User
 
Join Date: Sep 2002
Posts: 3
Durango is on a distinguished road
Wow!!! 18VDC Output?

In all my troubleshooting and testing of charging/battery system failures, I've never seen an altenator output approach 18VDC. Don't misunderstand me, I've dealt with overvoltage regulation failures, but I 've never allowed a voltage reading to go that high before I realize I have a problem. If charging system voltage goes past 15VDC, you have a regulation problem that needs to be investigated. Typically, a regulator will clamp the voltage on the high end around 14.5-14.8VDC depending on RPM and current demand. The most common failures are the inability of the altenator to produce the proper amount of voltage/current or none at all. Obviously, if you have replaced the altenator/voltage regulator with a OEM part or suitable equivalent, and the problem still exist, a wiring/connection fault is the problem. Get a hold of a good wiring schematic of the altenator/voltage regulator circuit and peform the proper voltage drop test throughout the circuit. This type of failure in my experience is unique/rare.
Reply With Quote
  #8  
Old 09-23-2002, 01:01 PM
miatasc miatasc is offline
Registered User
 
Join Date: Sep 2002
Location: Louisiana
Posts: 3
miatasc is on a distinguished road
18volts

I have checked the wiring with a mazda shop manuel and ever thing looks o.k. I've heard that the ECU could be the problem. Ant ideas?
Reply With Quote
  #9  
Old 09-28-2002, 10:54 AM
airplanemech
Guest
 
Posts: n/a
yeah 18 is way too high. normal is 14.25v. hint, as other people say that is the "regulator" job to do. maybe try another gauge or such.
Reply With Quote
Reply


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

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Fuel pump will not stop running Harleyearl Your Own Projects 4 08-17-2004 07:03 PM
94 Stang running hot Racerock Your Own Projects 10 08-01-2004 08:35 AM
Engine running hot while standing still Alwaysdutch Your Own Projects 9 06-18-2004 12:52 AM
305 High Output cvgrappler Off Topic 3 11-02-2002 10:25 PM
engine running rich racingisfun Your Own Projects 0 12-29-2001 03:09 PM


All times are GMT -4. The time now is 06:48 PM.


Powered by vBulletin® Version 3.8.2
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
TwoGuysGarage.com © Brenton Productions