Fixing a jimmy rigged electrical system

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jfrancom101

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Based on what I have seen so far, there is a possibility that you shouted the blue wire that is coiled up, which could have blown a fuse that powers the dist. Need to check fuses to cross that off the list.

I have to drive to the far side of town to trouble shoot camera wiring on a half million dollar motor home right now, I will check back in when I get done.
I'll look for fuses. I haven't seen a normal fuse box like on several trucks, but I'll look again and check inside the truck as well
 

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I had to work late, sorry. Would you please check to see if you can get 12 volts on the red wire at the distributor, with the key in the start and the run position? I'm going to study the wiring diagram tonight and check back in the morning. A picture of the fuel relays and terminal block/fusible link on the firewall and a picture of battery connections would be helpful if possible too.
 

WP29P4A

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I'm hoping SirRobynO will help out with the fuel pump mystery, He sees a lot of vehicles and can hopefully let you know if it is adequate or if it needs to be replaced. I have a hard time believing it puts out enough GPH to keep up with a v8.
 

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this is not an 85 so your fuse box may be larger, but its down by the e brake pedal(see the ratchet for it on the left) at the base of steering column by the firewall. its annoying spot but you should be able to get a good shot with the camera at it then look at the wires and see whats going on from a distance
 

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SirRobyn0

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I'm hoping SirRobynO will help out with the fuel pump mystery, He sees a lot of vehicles and can hopefully let you know if it is adequate or if it needs to be replaced. I have a hard time believing it puts out enough GPH to keep up with a v8.
You bet.

Here is what I've got. So that fuel pump is made by Mr Gasket. It's specs are 3.5 PSI, 28GPH. I would characterize this pump as lower end. I can order one wholesale for $22, so I'd image production cost is less than $10. 3.5PSI and 28 GPH is ok, it's on the lower end of what most mechanical pumps produce, however it looks like that electric pump is mounted in the engine compartment, is that correct? Electric pumps and not very good at sucking gas, so they should be mounted as close to the fuel tank as possible and that is why new vehicles have them mounted in the tank. So having it mounted in the engine compartment it's going to produce a little less than spec and it's going to live a very shortened life, especially given that it is a low quality pump to begin with. Have you checked to make sure that the is actually pumping gas?
 

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You bet.

Here is what I've got. So that fuel pump is made by Mr Gasket. It's specs are 3.5 PSI, 28GPH. I would characterize this pump as lower end. I can order one wholesale for $22, so I'd image production cost is less than $10. 3.5PSI and 28 GPH is ok, it's on the lower end of what most mechanical pumps produce, however it looks like that electric pump is mounted in the engine compartment, is that correct? Electric pumps and not very good at sucking gas, so they should be mounted as close to the fuel tank as possible and that is why new vehicles have them mounted in the tank. So having it mounted in the engine compartment it's going to produce a little less than spec and it's going to live a very shortened life, especially given that it is a low quality pump to begin with. Have you checked to make sure that the is actually pumping gas?
Can confirm everything he said.
My truck came with one of them (no provisions for mechanical pump on my engine) hooked up in the engine bay. It lasted about 1 tank of gas and quit pumping. Replacement lasted a couple tanks and died.
I’ve since wired it up properly and relocated down near the tank switches.
No telling how much longer it will last and it definitely is a cheap ass alternative to a good electric fuel pump. I still consider it temporary and would not trust it for any distance.

That said, even with questionable wiring pulling fuel uphill from 10’ away, it made enough fuel for full throttle pulls with a 454 and a thirsty carb.
 

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You bet.

Here is what I've got. So that fuel pump is made by Mr Gasket. It's specs are 3.5 PSI, 28GPH. I would characterize this pump as lower end. I can order one wholesale for $22, so I'd image production cost is less than $10. 3.5PSI and 28 GPH is ok, it's on the lower end of what most mechanical pumps produce, however it looks like that electric pump is mounted in the engine compartment, is that correct? Electric pumps and not very good at sucking gas, so they should be mounted as close to the fuel tank as possible and that is why new vehicles have them mounted in the tank. So having it mounted in the engine compartment it's going to produce a little less than spec and it's going to live a very shortened life, especially given that it is a low quality pump to begin with. Have you checked to make sure that the is actually pumping gas?
Thank you , good to know. I don't think it's his primary problem, but it should be on the todo list of things to correct for reliability. Are we in agreement that powering the fuel pump off the dist is not a good idea?
 

WP29P4A

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Was the blue wire coiled up like it shows in the pic, or did you coil it up? One of the first things we need to do is replace the connector on the end of the red wire where it connects to the Dist, and trace it back to where it comes from. Leave the yellow wire that goes to the fuel pump lose for right now. We will run a new wire for the fuel pump so it's not powered from the Dist.

I'm thinking we start with getting the starter to turn over first, then we get spark, then we deal with the fuel pump. Unless you want/need to do things in a different order. Your project, so you let me know what you need to move forward.

You should have a fuse labeled "IGN" we need to make sure it is good.
 

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Thank you , good to know. I don't think it's his primary problem, but it should be on the todo list of things to correct for reliability. Are we in agreement that powering the fuel pump off the dist is not a good idea?
Yea, that's a terrible idea, and would never do that.

I really don't know how many amps that pump draws, but lets say for the sake of discussion that it's 5 amps, going to the one wire that powers the distributor. That one wire was never meant to power a motor, doing that is going to cause a voltage drop in the wiring to the distributor, so it's getting fed lower voltage than it should be.

The best way to wire an electric pump would be though a relay, second best would be a key on power off the fuse box.

Also in the current set up not only is it likely that the distributor is getting less voltage than it should, it's very likely that the fuel pump is seeing reduced voltage. Lower voltage to a motor, increases amp draw, increases heat, and shortens the life of the fuel pump.

Ya, I'd say that really needs to be sorted out properly.

@jfrancom101 so if it was converted to a gas 350, you should be able to run a factory mechanical fuel pump. I'm sure there is no push rod under the pump plate in the motor, so you'd need to get one of those, plus a pump. Then depending on the pump you choose possible a regulator. If you decide to convert to mechanical pump we can talk more about the options then.
 

SirRobyn0

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Was the blue wire coiled up like it shows in the pic, or did you coil it up? One of the first things we need to do is replace the connector on the end of the red wire where it connects to the Dist, and trace it back to where it comes from. Leave the yellow wire that goes to the fuel pump lose for right now. We will run a new wire for the fuel pump so it's not powered from the Dist.

I'm thinking we start with getting the starter to turn over first, then we get spark, then we deal with the fuel pump. Unless you want/need to do things in a different order. Your project, so you let me know what you need to move forward.

You should have a fuse labeled "IGN" we need to make sure it is good.
That is the order I would go in as well. Kind of hard to troubleshoot spark or fuel in a vehicle that won't turn over.
 

jfrancom101

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I had to work late, sorry. Would you please check to see if you can get 12 volts on the red wire at the distributor, with the key in the start and the run position? I'm going to study the wiring diagram tonight and check back in the morning. A picture of the fuel relays and terminal block/fusible link on the firewall and a picture of battery connections would be helpful if possible too.
Sorry for the delay. I got the pictures. I tested and got zero positive connection, however on the on wire I did get 12c volts of ground though.
I think that the picture I got of the fire wall is the fusible link that you're talking about but I'm not positive. The fuse box was under the stering column. A couple of the 30 amp fuses are blown, I will try and get those replaced as soon as possbile. could have something to do with the problem for sure
 

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jfrancom101

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this is not an 85 so your fuse box may be larger, but its down by the e brake pedal(see the ratchet for it on the left) at the base of steering column by the firewall. its annoying spot but you should be able to get a good shot with the camera at it then look at the wires and see whats going on from a dis
this is not an 85 so your fuse box may be larger, but its down by the e brake pedal(see the ratchet for it on the left) at the base of steering column by the firewall. its annoying spot but you should be able to get a good shot with the camera at it then look at the wires and see whats going on from a distance
Thanks. I found mine rigjht by the steering column like you said
 

jfrancom101

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You bet.

Here is what I've got. So that fuel pump is made by Mr Gasket. It's specs are 3.5 PSI, 28GPH. I would characterize this pump as lower end. I can order one wholesale for $22, so I'd image production cost is less than $10. 3.5PSI and 28 GPH is ok, it's on the lower end of what most mechanical pumps produce, however it looks like that electric pump is mounted in the engine compartment, is that correct? Electric pumps and not very good at sucking gas, so they should be mounted as close to the fuel tank as possible and that is why new vehicles have them mounted in the tank. So having it mounted in the engine compartment it's going to produce a little less than spec and it's going to live a very shortened life, especially given that it is a low quality pump to begin with. Have you checked to make sure that the is actually pumping gas?
I was pumping gas, I recently stopped getting gas but its becuase I ran out. So i just filleda gas can back up and should be in business for now at least
 

jfrancom101

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2500 sierra
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Was the blue wire coiled up like it shows in the pic, or did you coil it up? One of the first things we need to do is replace the connector on the end of the red wire where it connects to the Dist, and trace it back to where it comes from. Leave the yellow wire that goes to the fuel pump lose for right now. We will run a new wire for the fuel pump so it's not powered from the Dist.

I'm thinking we start with getting the starter to turn over first, then we get spark, then we deal with the fuel pump. Unless you want/need to do things in a different order. Your project, so you let me know what you need to move forward.

You should have a fuse labeled "IGN" we need to make sure it is good.
I think that order sounds great to me. I'll get that going and try and see where the red on goes to. It goes into one of those wire harness covers so I proably have to cut that open, and follow it. I check again on the fuse
 

jfrancom101

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Yea, that's a terrible idea, and would never do that.

I really don't know how many amps that pump draws, but lets say for the sake of discussion that it's 5 amps, going to the one wire that powers the distributor. That one wire was never meant to power a motor, doing that is going to cause a voltage drop in the wiring to the distributor, so it's getting fed lower voltage than it should be.

The best way to wire an electric pump would be though a relay, second best would be a key on power off the fuse box.

Also in the current set up not only is it likely that the distributor is getting less voltage than it should, it's very likely that the fuel pump is seeing reduced voltage. Lower voltage to a motor, increases amp draw, increases heat, and shortens the life of the fuel pump.

Ya, I'd say that really needs to be sorted out properly.

@jfrancom101 so if it was converted to a gas 350, you should be able to run a factory mechanical fuel pump. I'm sure there is no push rod under the pump plate in the motor, so you'd need to get one of those, plus a pump. Then depending on the pump you choose possible a regulator. If you decide to convert to mechanical pump we can talk more about the options then.
Yeah. Eventually would a mechanical pump be a lot better? I don't know what the pump plate is, but I'm definetly not used to deisel engines. It's nice being able to learn more
 

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