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Old 01-03-2018, 12:59 AM   #1
Rufas
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Cleaning up engine bay wiring harness questions.

As my project is slowly nearing completion I'm cleaning up, i.e. trying to hide, the under hood wiring. I have a new harness (purchased about 20 years ago). This harness was setup for the external voltage regulator that would have been mounted on the core support.

I have a one wire alternator (internal regulator) that the output is connected directly to the starter. Then a battery cable from the starter to the battery. I have a 6 terminal buss bar that connects to the positive of the battery. The buss bar is attached to the core support directly below the batter tray. The main harness fusible link is connected to that buss bar. The buss bar also has connections for my EFI fuel pump, electric radiator fans and air pump for the suspension air bags. Both the main harness and the harness going to the buss bar are routed behind the fenders and over the wheel wells. All connections from the buss bar are either circuit breaker or fuse protected. I do not have any factory gauges. All gauges have been replaced with the equivalent Auto Meter gauges. With the exception of not having a amp meter. I'm running the headlight harness under the core support.

I've reviewed the factory wiring schematics and it appears that I can cut the wires from the main harness that lead to the alternator. This includes the red wire that is normally connected to the alternator output and the blue and white wires that plug into the alternator. This includes cutting off the harness that would have been connected to the external regulator.

Since I don't have factory gauges I would like to remove both the 4 amp fuse holders that are normally used for the factory amp gauge.

I think I can remove the above without causing problems or is my thinking flawed?
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Old 01-03-2018, 03:40 PM   #2
Rufas
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Re: Cleaning up engine bay wiring harness questions.

What no comments and almost 100 views.

Come on you electrical gurus lets hear some comments.

TIA
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Old 01-03-2018, 05:58 PM   #3
VetteVet
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Re: Cleaning up engine bay wiring harness questions.

Well you posted at midnight last night and later today so we may not have seen your thread. There are 50K members on this forum so 100 views isn't so much.

What you are considering is doable but I would not use a one-wire alternator, and I would not wire the alternator output to the starter cable. In fact I have done almost the same thing you are contemplating except I don't have EFI and the air compressors.

You have your buss bar located under the battery tray and mine is where the external regulator mounted. My alternator is mounted on the right side of the engine and I ran my wires from it to the buss bar. I have the 100 amp three wire alternator so I made a harness to run the wires down the front of the block to the right frame rail and over to the buss bar. I re-clocked the alternator to the six o'clock position so the wires were hidden and also easier to run without looping them over the water pump or down to the frame.

As far as the one-wire alternator goes, with the current loads you have I don't think it will do the job. The voltage sensing for the internal regulator is taken right at the alternator so you may see lower voltage downstream in the harness. With the three wire, the voltage sensing wire can be connected to the buss bar. Also I would use a CS 144 or even an ad 244 for the air bags.

I didn't have the gauges or the 4 amp fuse holders in my harness so that wasn't a factor.
I unwrapped the harness and removed the soldered junction along with the EVR wires, except for the alternator exciter 16 gauge brown wire which I ran to the buss bar, and then to the internally regulated alternator. You will want to upgrade the alternator output wire to at least an 8 gauge wire to the buss bar or to the starter.

You must have relays for the fuel pump, and the compressors, and for the fans. You will probably want to upgrade to the headlight relays as well, and even a relay for the ignition switch.
What ignition system do you have?

Here's my buss bar.

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The new harness routing.

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The alternator wiring.

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and the engine.

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I was going to run the main harness under the left inner fender, but it wouldn't reach so i ran it along the left frame rail.
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Old 01-03-2018, 10:39 PM   #4
Rufas
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Re: Cleaning up engine bay wiring harness questions.

Quote:
Originally Posted by VetteVet View Post
Well you posted at midnight last night and later today so we may not have seen your thread. There are 50K members on this forum so 100 views isn't so much.

What you are considering is doable but I would not use a one-wire alternator, and I would not wire the alternator output to the starter cable. In fact I have done almost the same thing you are contemplating except I don't have EFI and the air compressors.

You have your buss bar located under the battery tray and mine is where the external regulator mounted. My alternator is mounted on the right side of the engine and I ran my wires from it to the buss bar. I have the 100 amp three wire alternator so I made a harness to run the wires down the front of the block to the right frame rail and over to the buss bar. I re-clocked the alternator to the six o'clock position so the wires were hidden and also easier to run without looping them over the water pump or down to the frame.

As far as the one-wire alternator goes, with the current loads you have I don't think it will do the job. The voltage sensing for the internal regulator is taken right at the alternator so you may see lower voltage downstream in the harness. With the three wire, the voltage sensing wire can be connected to the buss bar. Also I would use a CS 144 or even an ad 244 for the air bags.

I didn't have the gauges or the 4 amp fuse holders in my harness so that wasn't a factor.
I unwrapped the harness and removed the soldered junction along with the EVR wires, except for the alternator exciter 16 gauge brown wire which I ran to the buss bar, and then to the internally regulated alternator. You will want to upgrade the alternator output wire to at least an 8 gauge wire to the buss bar or to the starter.

You must have relays for the fuel pump, and the compressors, and for the fans. You will probably want to upgrade to the headlight relays as well, and even a relay for the ignition switch.
What ignition system do you have?


I was going to run the main harness under the left inner fender, but it wouldn't reach so i ran it along the left frame rail.
I've pretty much done what you have suggested. My drivers side one wire alternator is a Powermaster 170amp CS144 has been clocked so the output is near the bottom with a 8 gauge cable to the starter and a four gauge from the starter to the battery. I have a 4 gauge cable from the positive battery to a 150 amp fuse that is then connected to the buss bar.

All high amp units, fuel pump, electric fans and air compressor are relay controlled and connected to the buss bar. I purchased the air compressor from Ride Tech about 20 years ago. It's output and current draw is small compared to what is being sold today. Each load is also protected by circuit breakers. I've also used the mesh wire wrap on all parts of the harness.

I like your suggestion on how to remove the EVR wires and will look into doing that.

I'm running the same alternator output to starter on my 468 BBC 1967 Olds Cutlass. With the exception the starter cable runs to the battery in the trunk. I've had that setup for seven years without issues. I'm not sure why you suggest not wiring the alternator to the starter. Connected directly to the battery or directly to the starter is electrically the same connection. Not arguing, just curious.

I'm thinking I might run two 8 gauge wires to the starter instead of the one I have now.

My ignition system is usual HEI setup, nothing special about that.

To clean things up I'll remove the two 4 amp fuse holders used for the factory amp meter. Right now they are not connected to anything.

Thanks for your suggestions
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Old 01-04-2018, 12:03 AM   #5
VetteVet
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Re: Cleaning up engine bay wiring harness questions.

Hi Rufus thanks for the feedback. I didn't know what alternator you had but now it makes more sense. The CS 144 will most likely deliver all the current you need
and The 95 and later alternators do not use the sensing wire. Their internal regulators are sensitive enough to pick up any voltage draw and compensate for that. Do you have to blip the throttle to get the alternator to charge after the initial start-up? If not then the alternator may have enough residual magnetism to compensate for that, whereas the older one-wires do not.

I'm pretty confident you are covered on the fusing for the loads you have, based on your reply.

As to the alternator routing, the alternator is the main current supplier for the loads in the vehicle and it charges the battery as a secondary function. You don't need to have the large alternator wire running to the battery and then to the main junction. It is the same connection but you have to be sure the wire from the battery to the main junction is the same size as the alternator output wire. In your case you can run the large alternator output wire to the main junction then run a smaller wire back to the battery. You wouldn't need to go to the solenoid and it'd save you some wire.

Here's an example. Ignore the small battery.


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Here's another. It's like my version but with the charging wire from the distribution block (junction) going to the solenoid to the battery main cable. instead of back to the positive terminal on the battery.

Name:  modified Wiring2.jpg
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The alternator is an SI with the sensing wire which you don't need.


This one is more like what we have with my routing.

Name:  Weston's diagram.jpg
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AS you can see there are many ways to do this so whatever suits a person can be correct as long as the basics are covered.
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Old 01-04-2018, 02:16 AM   #6
Rufas
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Re: Cleaning up engine bay wiring harness questions.

Quote:
Originally Posted by VetteVet View Post
Hi Rufus thanks for the feedback. I didn't know what alternator you had but now it makes more sense. The CS 144 will most likely deliver all the current you need
and The 95 and later alternators do not use the sensing wire. Their internal regulators are sensitive enough to pick up any voltage draw and compensate for that. Do you have to blip the throttle to get the alternator to charge after the initial start-up? If not then the alternator may have enough residual magnetism to compensate for that, whereas the older one-wires do not.

I'm pretty confident you are covered on the fusing for the loads you have, based on your reply.

As to the alternator routing, the alternator is the main current supplier for the loads in the vehicle and it charges the battery as a secondary function. You don't need to have the large alternator wire running to the battery and then to the main junction. It is the same connection but you have to be sure the wire from the battery to the main junction is the same size as the alternator output wire. In your case you can run the large alternator output wire to the main junction then run a smaller wire back to the battery. You wouldn't need to go to the solenoid and it'd save you some wire.

Here's an example. Ignore the small battery.

Here's another. It's like my version but with the charging wire from the distribution block (junction) going to the solenoid to the battery main cable. instead of back to the positive terminal on the battery.


The alternator is an SI with the sensing wire which you don't need.


This one is more like what we have with my routing.

AS you can see there are many ways to do this so whatever suits a person can be correct as long as the basics are covered.
Can't really answer the 'blip' question. The engine has only run enough for the initial breakin period.

Trying to keep the wiring clean/hidden the output to the starter, to battery is the shortest distance to the battery. I'm trying to keep all engine wires exiting behind the engine and nothing going forward just hanging in the air.

I would like to get my truck wiring like my Cutlass. Just about all wiring is hidden.

Thanks for your examples. It helps a lot.

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Old 01-04-2018, 11:11 AM   #7
VetteVet
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Re: Cleaning up engine bay wiring harness questions.

Very nice, I see why you want to hide the wiring.
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