How to Replace a Voltage Regulator in a 951
02-12-2008, 03:19 AM
#1
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How to Replace a Voltage Regulator in a 951
Very Carefully!
Problem: Battery gauge is either showing 12 or less than 12 volts or goes between 14 volts and 12 volts. I noticed that my headlights were dim and battery gauge was at about 11 volts, i reved the engine quickly to about 4.5krpm and the battery voltage gauge was at about 14v and eventually dropped down to 12v and slowly dropped until i'd rev it up again.
$25~ Dollar Solution: Replace Voltage regulator (price is from autozone, I bought mine for $16, I work in a shop, pelican wants something like $70 or so)
$150+ Solution: Replace Alternator
How to replace voltage regulator without removing the alternator:
(this is all from memory)
***WARNING: Be sure to disconnect battery. You have little room to work with so you might cut the backs of your hands on the plastic ducting for the alternator.***
Removal:
1. Disconnect battery
2. Remove air filter box (with attached afm)
3. Remove intercooler-to-throttlebody piping
4. Remove nuts that hold the plastic air ducting to alternator (1/4 drive ratchet with a swivel joint will most likely need to be used,(you can get away with removing 3, the top two and bottom drivers side, be careful as to not damage the plastic piece, if you break off a corner it'd most likely still be useable) NOTE: After you pull the ducting back, be careful as to not drop anything into the ducting, you might have one heck of a time recovering whatever falls in there.
5. Remove nut and red wire from the positive terminal on alternator
6. Remove two screws (blade/flat tip style) that hold Voltage Regulator on (you will need a stubby screwdriver or a screw driver that has a flexible shaft)
7. Inspect Voltage Regulator, if brushes (two metal prongs) are hardly sticking out, they are worn, if there appears to be plenty of metal you may or may not have another issue.
To Install
1. Try to clean up the contact rails inside the alternator if possible (if you stick your fingers inside the alternator and feel upwards, you can feel them) You should either rotate your engine or loosen up the accessory belt so you can spin the alternator. (I didn't do this and currently have no issues)
2. Place voltage regulator inside alternator, the brushes (metal prongs) will face upwards (towards the middle of the alternator)
3. ***Difficult Step*** Install screws, to make things easy, if you have a drill set, find a small drill about the same diameter as the bolts for the Voltage Regulator. Pull the voltage regulator upwards (while its in the alternator) and push the drill into the screw hole (the round side, not the actual drill portion of the bit) Now you can rotate the voltage regualtor so the other screw will fit in place, tighten it down and then remove the bit and install screw.
4. Install red wire and nut to alternator
5. Install air ducting and the 3 or 4 nuts for alternator
6. Install intercooler-to-throttlebody tube
7. Install air filter + afm
8. Reconnect battery
9. Start car and check gauge
***If gauge reads higher than 14, check with a mutli-meter***
My 951 shows a little over 15volts, however it actually runs steady at 14.1 volts. A friend's shows 12 volts, however it's actually pushing out about 13.85 volts. Be sure that no accessories are on while you are testing as they will cause a voltage drop.
Good luck!
Problem: Battery gauge is either showing 12 or less than 12 volts or goes between 14 volts and 12 volts. I noticed that my headlights were dim and battery gauge was at about 11 volts, i reved the engine quickly to about 4.5krpm and the battery voltage gauge was at about 14v and eventually dropped down to 12v and slowly dropped until i'd rev it up again.
$25~ Dollar Solution: Replace Voltage regulator (price is from autozone, I bought mine for $16, I work in a shop, pelican wants something like $70 or so)
$150+ Solution: Replace Alternator
How to replace voltage regulator without removing the alternator:
(this is all from memory)
***WARNING: Be sure to disconnect battery. You have little room to work with so you might cut the backs of your hands on the plastic ducting for the alternator.***
Removal:
1. Disconnect battery
2. Remove air filter box (with attached afm)
3. Remove intercooler-to-throttlebody piping
4. Remove nuts that hold the plastic air ducting to alternator (1/4 drive ratchet with a swivel joint will most likely need to be used,(you can get away with removing 3, the top two and bottom drivers side, be careful as to not damage the plastic piece, if you break off a corner it'd most likely still be useable) NOTE: After you pull the ducting back, be careful as to not drop anything into the ducting, you might have one heck of a time recovering whatever falls in there.
5. Remove nut and red wire from the positive terminal on alternator
6. Remove two screws (blade/flat tip style) that hold Voltage Regulator on (you will need a stubby screwdriver or a screw driver that has a flexible shaft)
7. Inspect Voltage Regulator, if brushes (two metal prongs) are hardly sticking out, they are worn, if there appears to be plenty of metal you may or may not have another issue.
To Install
1. Try to clean up the contact rails inside the alternator if possible (if you stick your fingers inside the alternator and feel upwards, you can feel them) You should either rotate your engine or loosen up the accessory belt so you can spin the alternator. (I didn't do this and currently have no issues)
2. Place voltage regulator inside alternator, the brushes (metal prongs) will face upwards (towards the middle of the alternator)
3. ***Difficult Step*** Install screws, to make things easy, if you have a drill set, find a small drill about the same diameter as the bolts for the Voltage Regulator. Pull the voltage regulator upwards (while its in the alternator) and push the drill into the screw hole (the round side, not the actual drill portion of the bit) Now you can rotate the voltage regualtor so the other screw will fit in place, tighten it down and then remove the bit and install screw.
4. Install red wire and nut to alternator
5. Install air ducting and the 3 or 4 nuts for alternator
6. Install intercooler-to-throttlebody tube
7. Install air filter + afm
8. Reconnect battery
9. Start car and check gauge
***If gauge reads higher than 14, check with a mutli-meter***
My 951 shows a little over 15volts, however it actually runs steady at 14.1 volts. A friend's shows 12 volts, however it's actually pushing out about 13.85 volts. Be sure that no accessories are on while you are testing as they will cause a voltage drop.
Good luck!
02-12-2008, 10:19 AM
#2
Addict
Rennlist Member
Rennlist Member
Nice writeup. Also if you have the Vreg out you can do the diode mod to raise your charging voltage a bit.
http://www.detomaso.nu/~thomast/alternator/
Not really necessary unless you have a big amp or the like.
-Joel.
http://www.detomaso.nu/~thomast/alternator/
Not really necessary unless you have a big amp or the like.
-Joel.
02-12-2008, 12:26 PM
#3
Three Wheelin'
Join Date: Jun 2003
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the gage can be calibrated to a decent dvm.
you have to split the case and there's a small set screw next to the voltage gage where you make the adjustment.
an adjustable vr is another alternative.
87951
you have to split the case and there's a small set screw next to the voltage gage where you make the adjustment.
an adjustable vr is another alternative.
87951
