Big 3 Upgrade Installed
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Joined: Dec 2011
Posts: 79
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From: Fort Worth Texas
St. Jude Donor '12
Just had a Big 3 installed with my new system. In my JL 900/5's FAQ, it suggests it for systems having dips in voltage leading to amps shutting off intermittently. it's a fairly mainstream mod.
When I put a new motor in my 58 truck in the late 70's we definitely upgraded the wiring, we did not give it a name like it has acquired the last few years, but, IMHO, it's the same thing.
When I put a new motor in my 58 truck in the late 70's we definitely upgraded the wiring, we did not give it a name like it has acquired the last few years, but, IMHO, it's the same thing.
Race Director
Joined: Apr 2007
Posts: 11,150
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From: South Western Ontario
OK, what's with that 20A fuse block on #4 wire??????
The need to do this on a stock car is very questionable. Obviously, this mod really didn't really help anything and you still have a connection issue in the car. Fixing poor connections will help more than tacking on extra wiring to try and mask the problem.
It's usually PVC jacketed which would be no worse than the stuff used on the OEM wires.
You want good wire then get DLO with 150C rated insulation. Using a torch to solder the wire will barely singe the insulation.
The need to do this on a stock car is very questionable. Obviously, this mod really didn't really help anything and you still have a connection issue in the car. Fixing poor connections will help more than tacking on extra wiring to try and mask the problem.
You want good wire then get DLO with 150C rated insulation. Using a torch to solder the wire will barely singe the insulation.
Last edited by lionelhutz; Jul 5, 2012 at 02:56 PM.
Thread Starter
Le Mans Master
Joined: May 2006
Posts: 6,774
Likes: 363
From: Midland TX
The 20-Amp fuse size came from another discussion I was reading on this forum when researching this ahead of time. Lots of disagreement. I could be wrong, but as I recall, it was Bill Curlee that suggested a 20-Amp fuse?
Obviously, a 4-Gage "wire" can handle WAY MORE that 20 amps, but 4-gage is also tons of overkill (but it does not hurt to go larger than needed - at least I did not go 0/1 Gage as many suggested). In the case of a short, I would want the secondary wiring to blow a fuse before the current exceeded 20 amps - which I believe is the most the stock system is designed to handle?
I did find one post here (#19) that has some info...
http://forums.corvetteforum.com/c5-t...big-three.html
Obviously, a 4-Gage "wire" can handle WAY MORE that 20 amps, but 4-gage is also tons of overkill (but it does not hurt to go larger than needed - at least I did not go 0/1 Gage as many suggested). In the case of a short, I would want the secondary wiring to blow a fuse before the current exceeded 20 amps - which I believe is the most the stock system is designed to handle?
I did find one post here (#19) that has some info...
http://forums.corvetteforum.com/c5-t...big-three.html
Tech Contributor
Joined: Jan 2007
Posts: 19,401
Likes: 1,143
From: Dyer, IN
The 20-Amp fuse size came from another discussion I was reading on this forum when researching this ahead of time. Lots of disagreement. I could be wrong, but as I recall, it was Bill Curlee that suggested a 20-Amp fuse?
Obviously, a 4-Gage "wire" can handle WAY MORE that 20 amps, but 4-gage is also tons of overkill (but it does not hurt to go larger than needed - at least I did not go 0/1 Gage as many suggested). In the case of a short, I would want the secondary wiring to blow a fuse before the current exceeded 20 amps - which I believe is the most the stock system is designed to handle?
I did find one post here (#19) that has some info...
http://forums.corvetteforum.com/c5-t...big-three.html
Obviously, a 4-Gage "wire" can handle WAY MORE that 20 amps, but 4-gage is also tons of overkill (but it does not hurt to go larger than needed - at least I did not go 0/1 Gage as many suggested). In the case of a short, I would want the secondary wiring to blow a fuse before the current exceeded 20 amps - which I believe is the most the stock system is designed to handle?
I did find one post here (#19) that has some info...
http://forums.corvetteforum.com/c5-t...big-three.html
Thread Starter
Le Mans Master
Joined: May 2006
Posts: 6,774
Likes: 363
From: Midland TX
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St. Jude Donor '12,'13,'15,'16,'17
What amp range is the fusible link the runs from the starter to the alternator?
Thats what amp I would run.
Thats what amp I would run.
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Well,,,,,,,,,,,,,,,,,, Lets see if I can sort this info out and help everyone.
1. The Service Manual discusses using a JUMPER WIRE between the battery POS terminal and the Alternator BATT Terminal to see "IF" there are compromised connections between the BATT and POS terminals if charging ability is compromised.
It also states that a 10 AMP fuse be used in series with this TEMPORARY TEST WIRE in case the wire is accidentally shorted.
2. IF,,,,,,,,,,,,, I were to INCREASE the size of this wire,,, I would use a 60 amp to 100 amp fuse for wire protection. You can reach 100 amps in a microsecond and not damage that wire. The alternator uses that wire for suppling 12 VDC to the FIELD Coil and for the OUTPUT from the alternator to charge the battery and supply any loads the car may have and or any additional loads ADDED to the car.
3. The wiring that GM uses in our cars is the BARE MINIMUM needed to operate. Many of us have experienced damaged wiring when we attempt to add higher wattage headlights, bigger fuel pumps, high power AMPS,, ect, ect,,,,,,,, The C6 cars have serious issues with the COOLING FANS id the fans are reprogrammed to run longer. The issue is a poorly constructed fan power connector and a poor ground.
SO,,,,,,,,,,,,,,,,,,,,, Improving the MAIN wiring is recommended if your either having issues or adding aftermarket higher power parts.
Going in excess in increasing the size of the wiring will NOT hurt anything. Its like adding FANCY color engine parts or CHROME Parts..
Choreo
Your BIG THREE looks excellent. If it were me, I would increase the fuse to 60 amps and run the new wire inside the same wiring harness that runs down the drivers side of the intake manifold where the other alternator BATT Wire runs.
When you see the voltage drop LOW on the DIC Meter,, check the wire that supplies the IGNITION SWITCH with HOT at ALL TIMES power and see what it reads. Hopefully it reads the same as battery voltage reads.
Bill
1. The Service Manual discusses using a JUMPER WIRE between the battery POS terminal and the Alternator BATT Terminal to see "IF" there are compromised connections between the BATT and POS terminals if charging ability is compromised.
It also states that a 10 AMP fuse be used in series with this TEMPORARY TEST WIRE in case the wire is accidentally shorted.
2. IF,,,,,,,,,,,,, I were to INCREASE the size of this wire,,, I would use a 60 amp to 100 amp fuse for wire protection. You can reach 100 amps in a microsecond and not damage that wire.
The alternator uses that wire for suppling 12 VDC to the FIELD Coil and for the OUTPUT from the alternator to charge the battery and supply any loads the car may have and or any additional loads ADDED to the car.3. The wiring that GM uses in our cars is the BARE MINIMUM needed to operate. Many of us have experienced damaged wiring when we attempt to add higher wattage headlights, bigger fuel pumps, high power AMPS,, ect, ect,,,,,,,, The C6 cars have serious issues with the COOLING FANS id the fans are reprogrammed to run longer. The issue is a poorly constructed fan power connector and a poor ground.
SO,,,,,,,,,,,,,,,,,,,,, Improving the MAIN wiring is recommended if your either having issues or adding aftermarket higher power parts.
Going in excess in increasing the size of the wiring will NOT hurt anything. Its like adding FANCY color engine parts or CHROME Parts..
Choreo
Your BIG THREE looks excellent. If it were me, I would increase the fuse to 60 amps and run the new wire inside the same wiring harness that runs down the drivers side of the intake manifold where the other alternator BATT Wire runs.
When you see the voltage drop LOW on the DIC Meter,, check the wire that supplies the IGNITION SWITCH with HOT at ALL TIMES power and see what it reads. Hopefully it reads the same as battery voltage reads.
Bill
Thread Starter
Le Mans Master
Joined: May 2006
Posts: 6,774
Likes: 363
From: Midland TX
Choreo
Your BIG THREE looks excellent. If it were me, I would increase the fuse to 60 amps and run the new wire inside the same wiring harness that runs down the drivers side of the intake manifold where the other alternator BATT Wire runs.
When you see the voltage drop LOW on the DIC Meter,, check the wire that supplies the IGNITION SWITCH with HOT at ALL TIMES power and see what it reads. Hopefully it reads the same as battery voltage reads.
Bill
I also will re-route the Alternator to Battery wire. Doesn't the stock alternator hot wire harness take the path I showed with the red overlay in the photo in my post #9 (i.e. routing under the fuel line connection)?
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St. Jude Donor '12,'13,'15,'16,'17
Great info Bill!
Do you know what the fusible link is rated for the goes from the Alt to the starter?
Than you!
Do you know what the fusible link is rated for the goes from the Alt to the starter?
Than you!
Pro
Joined: May 2003
Posts: 687
Likes: 228
From: Kemah Texas
No, I am not adding a battery or changing the alternator - all I have is the stock radio. I just did this to help strengthen the stock wiring and hoping that it might help me diagnose the voltage drop I get at traffic lights when stopped and the engine is warm. No such luck, but at least that eliminates the primary wiring as the culprit and should not "hurt" to have the extra system in place.
I previously replaced the battery, the alternator, the starter and the ignition switch at different times (with new stock GM replacements except for the Optima battery of which I have had three), but I have had this voltage drop problem for years now - very frustrating. When the engine first starts up cold, the voltage is always fine (about 13.8v on the gauge which is about .6 volts below the reading at the battery). For the first 10-15 minutes of driving it is fine, after that every time I come to a stop the voltage slowly drops sometimes to about 11.2 volts on the gauge and sometimes the engine starts to stumble at that point like it is going ti die, so I throw it into neutral and it climbs back up. I get no codes. I have just gotten in the habit of throwing the transmission in neutral at every red light... bummer.
My best guess is that I got TWO new bad Valeo alternators (with bad regulators), but what are the odds? Dealership never could locate the problem, but they replaced both the alternator and starter under warranty trying to fix it.
One time I was able to clean the butterfly on the throttle body and that fixed the problem completely for a while for several months - so it was a mechanical fix to an electrical issue (something to do with an idle sensor as I recall). That fix has not worked since.
I previously replaced the battery, the alternator, the starter and the ignition switch at different times (with new stock GM replacements except for the Optima battery of which I have had three), but I have had this voltage drop problem for years now - very frustrating. When the engine first starts up cold, the voltage is always fine (about 13.8v on the gauge which is about .6 volts below the reading at the battery). For the first 10-15 minutes of driving it is fine, after that every time I come to a stop the voltage slowly drops sometimes to about 11.2 volts on the gauge and sometimes the engine starts to stumble at that point like it is going ti die, so I throw it into neutral and it climbs back up. I get no codes. I have just gotten in the habit of throwing the transmission in neutral at every red light... bummer.
My best guess is that I got TWO new bad Valeo alternators (with bad regulators), but what are the odds? Dealership never could locate the problem, but they replaced both the alternator and starter under warranty trying to fix it.
One time I was able to clean the butterfly on the throttle body and that fixed the problem completely for a while for several months - so it was a mechanical fix to an electrical issue (something to do with an idle sensor as I recall). That fix has not worked since.
The red flag should have been that you were able to temporarily fix the issue by cleaning the TB butterfly. I, and many others on CF, have had idle problems you described. If cleaning your TB teporarily fixed the issue you may have missed the other culprit, the MAF. If either one is dirty, you will have the low/eratic/hunting idle, and if the idle goes low/eratic enough, the voltage will drop as well. Try removing the MAF and hose it down with CRC spray MAF cleaner (parts store). Do the same with CRC spray TB cleaner (also parts store) on the TB. Dirty MAFs are common especially if you have a CAI with an oil-impregnated air filter. My C5 idled like new after the cleaning. Some suggest disconnect/reconnect the battery after cleaning so that the idle trims get re-learned. Hope this helps.
Last edited by tomlink; Jul 10, 2012 at 02:31 PM.
Thread Starter
Le Mans Master
Joined: May 2006
Posts: 6,774
Likes: 363
From: Midland TX
I've done the "Big Three" mod on my C5 to support my 1500Watts worth of audio amps. I've never noticed a change in voltage or idle quality based on the wiring.
The red flag should have been that you were able to temporarily fix the issue by cleaning the TB butterfly. I, and many others on CF, have had idle problems you described. If cleaning your TB teporarily fixed the issue you may have missed the other culprit, the MAF. If either one is dirty, you will have the low/eratic/hunting idle, and if the idle goes low/eratic enough, the voltage will drop as well. Try removing the MAF and hose it down with CRC spray MAF cleaner (parts store). Do the same with CRC spray TB cleaner (also parts store) on the TB. Dirty MAFs are common especially if you have a CAI with an oil-impregnated air filter. My C5 idled like new after the cleaning. Some suggest disconnect/reconnect the battery after cleaning so that the idle trims get re-learned. Hope this helps.
The red flag should have been that you were able to temporarily fix the issue by cleaning the TB butterfly. I, and many others on CF, have had idle problems you described. If cleaning your TB teporarily fixed the issue you may have missed the other culprit, the MAF. If either one is dirty, you will have the low/eratic/hunting idle, and if the idle goes low/eratic enough, the voltage will drop as well. Try removing the MAF and hose it down with CRC spray MAF cleaner (parts store). Do the same with CRC spray TB cleaner (also parts store) on the TB. Dirty MAFs are common especially if you have a CAI with an oil-impregnated air filter. My C5 idled like new after the cleaning. Some suggest disconnect/reconnect the battery after cleaning so that the idle trims get re-learned. Hope this helps.
I understand there is a Throttle Position Sensor somewhere as well, but don't know where it is or if it can be replaced by itself?
Pro
Joined: May 2003
Posts: 687
Likes: 228
From: Kemah Texas
On my C5, the Throttle Position Sensor is on the passenger side of the Throttle Body. A few years back, it was throwing a code and sent the car into low-power mode. The tech removed and cleaned the TB and have not had a problem since.
Based on your experience with temporarily alleviating the issue by cleaning the TB, I can't help thinking it must have something to do with the TB, MAF or wiring to either.
You might want to check DIY Autotech on Youtube. I saw some videos on how to check for the correct operation of the TPS with a multi-meter. I hope this helps.
Based on your experience with temporarily alleviating the issue by cleaning the TB, I can't help thinking it must have something to do with the TB, MAF or wiring to either.
You might want to check DIY Autotech on Youtube. I saw some videos on how to check for the correct operation of the TPS with a multi-meter. I hope this helps.
Last edited by tomlink; Jul 11, 2012 at 02:47 PM.
4th Gear
Joined: Sep 2015
Posts: 4
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I previously replaced the battery, the alternator, the starter and the ignition switch at different times (with new stock GM replacements except for the Optima battery of which I have had three), but I have had this voltage drop problem for years now - very frustrating. When the engine first starts up cold, the voltage is always fine (about 13.8v on the gauge which is about .6 volts below the reading at the battery). For the first 10-15 minutes of driving it is fine, after that every time I come to a stop the voltage slowly drops sometimes to about 11.2 volts on the gauge and sometimes the engine starts to stumble at that point like it is going ti die, so I throw it into neutral and it climbs back up. I get no codes. I have just gotten in the habit of throwing the transmission in neutral at every red light... bummer.
, and I'm not even a Corvette owner, but I was reading about the "big three" and found this post. On a different forum I found the following info about regulated voltage controllers on some GM vehicles. I'm posting it here, because *maybe* the Corvette has the same feature, in which case the drop in voltage isn't a problem at all. Just my thoughts. Hope it helps.-Phil
---------
Subject: Volt Gauge Fluctuation - keywords cluster electrical excessive fluctuation gage generator intermittent IPC operation volt voltage voltmeter wire #PIT3331A - (12/16/2005)
Models: 2005-2006 Cadillac Escalade Models
2005-2006 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2005-2006 GMC Sierra, Yukon Models
with RVC
--------------------------------------------------------------------------------
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Some customers may comment that their voltmeter is fluctuating between 12 and 14 volts on their full size pickup / utility vehicle.
Recommendation/Instructions:
Starting with the 2005 model year, light duty full size pickups and utilities, are equipped with a new Regulated Voltage Control (RVC) system. This system turns off the alternator when it is not required in order to improve fuel economy. The alternator will turn back on when additional voltage is required. This will cause the voltmeter to fluctuate between 12 and 14 volts as opposed to non-regulated systems which usually maintain a more consistent reading of 14 volts. This fluctuation with the RVC system is normal system operation and NO repairs should be attempted.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
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