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Gm alt conversion not charging.. Any info is appreciated!
Like the title says I did the gm alternator conversion on my 87 pickup. I bought the power master alternator from summit and the trail gear brackets. I followed this guys thread to the T with my install. Minus I could only find a 45 ohm 10watt resistor(only thing I could find in town) but I did wire it inline with the yellow wire.
https://www.yotatech.com/forums/f116/how-gm-1-wire-alternator-3-wire-toyota-264252/
now my problem is it's not charging. There was a paper with the new alternator about putting a socket on the pulley nut of the alternator and turning it clockwise and if the belt is tight enough it will turn the motor over and not just spin the pulley. It does do that so I'm good there. I have the sr5 cluster and my volt guage is only showing about 12v which means im running off battery....
Here is a pic of the stock alternator voltage before this conversion.
Here is a pic as of today after the alternator conversion
Any info is greatly appreciated to why this isn't charging now!!! Thanks!
i'm running that powermaster alternator, it's 140amp or something?
i didn't see any paperwork about turning the engine over from the alternator pulley, but i did get a paper that specifically said to not overtighten the belt, because it will wear out the bearing... i would make sure that it's plenty loose, remember that with 140amp potential, it'll put out a lot more juice at idle than the stock alternator.
i don't think that i used a resistor, and there isn't any resistor listed in the install pdf that's included in your thread link.
you ran the included wire all the back to the battery? that should be charging it.
do you know how to check car battery voltages with a multimeter, on the battery terminals? do that, to confirm what's actually happening.
[QUOTE=osv;52332992]i'm running that powermaster alternator, it's 140amp or something?
i didn't see any paperwork about turning the engine over from the alternator pulley, but i did get a paper that specifically said to not overtighten the belt, because it will wear out the bearing... i would make sure that it's plenty loose, remember that with 140amp potential, it'll put out a lot more juice at idle than the stock alternator.
i don't think that i used a resistor, and there isn't any resistor listed in the install pdf that's included in your thread link.
you ran the included wire all the back to the battery? that should be charging it.
do you know how to check car battery voltages with a multimeter, on the battery terminals? do that, to confirm what's actually happening.[/QUOTE
yes it's the 140amp power master. And the paper said something along the lines of don't void your warranty make sure ur belt is tight and then gave the instructions I explained in my original post. I may have it still and will take a pic when I get home. The paper was hanging on the pulley when I opened the box... I thought it was a bit weird to have it that tight as well!
I have a 4 gauge power wire running from the alt to the positive post on the battery. I did just pull my truck into the shop and started it up. Battery had 12.3v and with the truck running I put my neg end of my multimeter on the neg battery post and the positive on the pos terminal of the alternator that my 4 guage wire is coming off of and I got 12.5v... Something is up here for sure.
On to the resistor deal I didn't orignanlly have it on there. I thought that was maybe the problem and put it on today and still no charging. That's when I came here.
the resistor part is here in that guys post...
Just to verify how I have my wires connected to the 2 wire gm plug I bought here is that pic. Don't mind my ˟˟˟˟ty looking header. I have a lce one but my exhaust is 3in to long to fit it so I gotta head to the exhaust shop to have that done but I have bigger problems then that right now! Lol
Here is the pic straight from summit racing that was hanging on the pulley when I opened the box...
Last edited by Zpayne21; 08-29-2016 at 09:52 PM.
Reason: Pic
With key-on, engine off, does the "alt" light illuminate? If that bulb is burned out (or somehow not connected) your alternator won't be "excited."
That's the purpose of the resistor, to stand in for the alt light when (?) it burns out. By "parallel" they mean parallel to the alt light, which means from yellow wire to switched 12v. ("Parallel" confuses even me, so if you didn't get it right the first time, don't blame me.)
To test quickly: pull the alternator plug, check for 12v from yellow wire to ground with key-on.
With key-on, engine off, does the "alt" light illuminate? If that bulb is burned out (or somehow not connected) your alternator won't be "excited."
That's the purpose of the resistor, to stand in for the alt light when (?) it burns out. By "parallel" they mean parallel to the alt light, which means from yellow wire to switched 12v. ("Parallel" confuses even me, so if you didn't get it right the first time, don't blame me.)
To test quickly: pull the alternator plug, check for 12v from yellow wire to ground with key-on.
i did check with just the key on/engine off to see if the "alt" light came on and it didn't. I was on my way to getting the alternator out of the truck to go have it tested and then powermaster returned my phone call. After talking to him the first thing he asked me was are your brackets painted. I intially thought ˟˟˟˟ why didn't I think of that. Every bracket on this motor is powdercoated.... So he informed me there is an 8x1.25 threaded hole directly below the positive post on the bottom of the case for a ground wire to be attached to. I'm sure this is my problem!!!
As far as the resistor goes I have it wired directly inline with the yellow wire. That is the correct way right? When I get home I well check for 12v on that yellow wire with the neg lead of my multimeter grounded.
Thanks again for everyone that has chimed in! Hopefully this thread will help someone else down the road that runs into this same alternator problem
As far as the resistor goes I have it wired directly inline with the yellow wire. That is the correct way right?
Nope, inline is in series; If charge light bulb gets busted you will lose excitation.
You want a parallel path for 12V to still flow to your alt to excite it.
Connect one end of resistor to #1 yellow wire and (like Scope103 said) the other end to switched 12v. Switched 12V means point that only has 12V when, AND ONLY WHEN, ignition switch is on.
What point would I use? Strictly speaking, in order to parallel with Charge light, you'd connect it to fused side of IGN fuse, but that might be hard to access.
A more convenient and clean source would be the stock IG (red wire) that the phone screenshot is telling you not to use
Last edited by RAD4Runner; 08-30-2016 at 04:02 PM.
... When I get home I well check for 12v on that yellow wire with the neg lead of my multimeter grounded....
If you don't get 12v, your problem may not be your fancy-pants powder coating. I'd find that 12v before I horsed around with a separate ground wire. (To be fair, the ground wire won't hurt, it's just extra "stuff.") If you DO find 12v on the yellow wire, try shorting that wire directly to ground; that should turn on your ALT light.
Originally Posted by RAD4Runner
...A more convenient and clean source would be the stock IG (red wire) that the phone screenshot is telling you not to use
If you don't get 12v, your problem may not be your fancy-pants powder coating. I'd find that 12v before I horsed around with a separate ground wire. (To be fair, the ground wire won't hurt, it's just extra "stuff.") If you DO find 12v on the yellow wire, try shorting that wire directly to ground; that should turn on your ALT light.
Excellent!
i will try that out first! Right now I'm in the middle of pulling the head back off to switch the head gasket out again cause of a noob mistake and in hopes of trying to get my damn timing right. I just did a rebuild on this motor and it still is topping out at 60mph again like it was before. Minus this time I put 4.88 gears in since I have 35's and did all the bolt ons plus the 261 cam In my 22r. It should most def do 70-75mph comfortably from what I read.
If you don't get 12v, your problem may not be your fancy-pants powder coating. I'd find that 12v before I horsed around with a separate ground wire. (To be fair, the ground wire won't hurt, it's just extra "stuff.") If you DO find 12v on the yellow wire, try shorting that wire directly to ground; that should turn on your ALT light.
Excellent!
i did as scope said and ground my yellow wire and the charge light did come on in the cluster. I also checked to make sure I was getting 12v out of that same wire with the ignition on and I am. So I still believe I need to wire my resistor with one end connected to the yellow wire and the other connected to the red wire that is supposed to be unused during this conversion as rad4runner suggested so if the bulb does burn out my alternator will still be self excited. Also at this point I assume I will still need a ground to fix my problem completely.
i did as scope said and ground my yellow wire and the charge light did come on in the cluster. I also checked to make sure I was getting 12v out of that same wire with the ignition on and I am. .... Also at this point I assume I will still need a ground to fix my problem completely.
Sure sounds like it. Unless the alternator is broken internally, which sounds less likely than an inadequate ground connection. Also, easy to check: put in the bolt and attach a ground wire.
Sure sounds like it. Unless the alternator is broken internally, which sounds less likely than an inadequate ground connection. Also, easy to check: put in the bolt and attach a ground wire.
Kudos to Summit for spotting it so quickly.
Second that.
Also, O.P., just checking... You disconnected and left disconnected your stock "B" alt to battery (via fuse block) wire, correct?
Also, O.P., just checking... You disconnected and left disconnected your stock "B" alt to battery (via fuse block) wire, correct?
yes that stock wire is no longer connected. That and the block with the wire running to the fuse block is all taped up and zip tied away in the fender well for now. I plan on de pinning a lot of wiring since I desmogged my motor and only have maybe 6 plugs on this motor. I'm going to try it out here in about 30min and will post back to let u guys know what happens! Thanks again everyone that has chimed in!
YEAH! Good to know!
So the lack of proper ground was the culprit?
[QUOTE=Zpayne21;52333273]yes that stock wire is no longer connected. That and the block with the wire running to the fuse block is all taped up and zip tied away /QUOTE]
Cool.
Last edited by RAD4Runner; 08-31-2016 at 11:56 AM.
[QUOTE=RAD4Runner;52333283]YEAH! Good to know!
So the lack of proper ground was the culprit?
Yes sir that was the problem! Glad it's all worked out. Now on to my next problem of no power. I don't get what's going on with this motor.... I'll start a new thread and see if I can find out what's going on so I don't go on to another topic to help someone who is searching this same alternator problem in the future.
You disconnected and left disconnected your stock "B" alt to battery (via fuse block) wire, correct?
i wondered what happens if the big factory wire is left connected, so that it's basically in parallel to the new wire that goes directly back to the battery post.
I have a 4 gauge power wire running from the alt to the positive post on the battery.
Originally Posted by osv
i wondered what happens if the big factory wire is left connected, so that it's basically in parallel to the new wire that goes directly back to the battery post.
Stock "B" wire passes through fuse network in fuse block before reaching the battery positive post. As wired above, if stock "B" wire were left connected, that and the new 4-gauge wire will bypass the fuse protection, producing a dangerous circuit.
... I have a 4 gauge power wire running from the alt to the positive post on the battery.
Originally Posted by RAD4Runner
Stock "B" wire passes through fuse network in fuse block before reaching the battery positive post. As wired above, if stock "B" wire were left connected, that and the new 4-gauge wire will bypass the fuse protection, producing a dangerous circuit.
I didn't catch that; wiring the alternator directly to the battery post is pretty dangerous.
If that doesn't convince you, then how about: "it completely defeats the purpose of getting a big-ass alternator"? You don't need 140 amps to charge the battery; if the battery is taking more than about 30 amps it's not only irretrievably dead, it will probably explode. The reason you get an over-sized alternator is so you can run your winch, zombie lights and whomping buzz-box stereo all at the same time. With your alternator connected directly to the battery post, ALL of your drains are pulling power through the 80amp "alt" fuse. Which now sets the maximum you're ever going to get from both the battery and alternator combined.
Originally Posted by Zpayne21
... so if the bulb does burn out my alternator will still be self excited. ...
Well, to be technical, not quite. A so-called "one wire" alternator connection is when you talk about "self-excited." It's covered well in the article you linked to, if you care about nomenclature.
When I first started planning my B wire upgrade, I missed that too. Until I looked closer into schematic. - LOL!
... wiring the alternator directly to the battery post is pretty dangerous.
...The reason you get an over-sized alternator is so you can run your winch, zombie lights and whomping buzz-box stereo all at the same time. With your alternator connected directly to the battery post, ALL of your drains are pulling power through the 80amp "alt" fuse. Which now sets the maximum you're ever going to get from both the battery and alternator combined.....
Correct.
After-market systems should never take power from the stock fuse block. A stock fuse block take out by problems in after-market systems would be a nightmare. That was my concern when I was planning my alt and "B" wire upgrade.
To address that, my alternator positive post now connects to battery positive post via a separate fusible Link rated for my new "B" wire, instead of the "B" line on the power bus/ "point "B" on fuse block.
Winch power would be directly connected to battery positive.
Other after-market systems (sub-woofer power, lights, DC-AC inverter, etc) would take power from fused distribution block connected directly to battery positive post.
Battery and alt will now work hand in hand independent of the stock fuse block.
Any problem with after-market add-ons will be taken cared of by distribution block and will not affect stock protection circuit in stock fuse block.
08-29-2016, 02:36 PM
