I was gonna say, it concerns me more when I don't see puddles under my trucks...makes me think I'm too low on fluids then 
CK5
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'89 R3500 Crew Cab 2wd to 4wd conversion & beyond
- Thread starter mrk5
- Start date
Started out with 2wd TBI350 with SM465 to current 4wd with 454, 700r4, NP241
The 73 and 66 both leave puddles so I'm covered there.
I HATE oil leaks... but I also have three trucks with 465s and two with 205s so oil leaks happen...
At least my engines don’t leak enough to leave spots...
At least my engines don’t leak enough to leave spots...
Thought I had the fuel tank selector switch straightened up after spraying it with some contactor cleaner. Thought maybe it was just dust got in there messing with the actuator. Well, it did it to me again today; wouldn't select the right tank. I decided to pull the switch apart and one of the terminals didn't want to pull apart. I found this.
That terminal is for the right tank which is the one I'm having trouble selecting. My question is did this cause my troubles or is it a result of my troubles?
If it caused my troubles, why would that 1 terminal get so hot? I primarily run on the other tank so that terminal doesn't see a lot of electricity flow.
I think I'm leaning towards a bad switch causing this to happen. I think if it was something in the wire or the pump itself, I would have seen damage in the wire and not the switch. The wire is not discolored so it seems all the heat was in the switch.
I know many of you are thinking I should go to a K5/Burb tank.
That terminal is for the right tank which is the one I'm having trouble selecting. My question is did this cause my troubles or is it a result of my troubles?
If it caused my troubles, why would that 1 terminal get so hot? I primarily run on the other tank so that terminal doesn't see a lot of electricity flow.
I think I'm leaning towards a bad switch causing this to happen. I think if it was something in the wire or the pump itself, I would have seen damage in the wire and not the switch. The wire is not discolored so it seems all the heat was in the switch.
I know many of you are thinking I should go to a K5/Burb tank.
Yes you should
Think it is the switch though.
Think it is the switch though.
I second the single tank. The burned contact could’ve just been from a poor connection building heat.
Any time I have seen a burned up connection like that it is usually always from poor contact at the terminals themselves causing excessive resistance and heat. If the fuse for the circuit did not pop and the wiring is not melted I would not go chasing a ghost short. I would replace the entire pigtail and switch and move on or go to a blazer tank.
You could be lucky like me and have the only single 20 gal saddle tank big block truck ever. I don't know why you would ever order a truck that way but it is no fun. Maybe they wanted to limit the distance the driver could go(it was a county road dept truck).
You could be lucky like me and have the only single 20 gal saddle tank big block truck ever. I don't know why you would ever order a truck that way but it is no fun. Maybe they wanted to limit the distance the driver could go(it was a county road dept truck).
Is the 20 gallon tank rare? My 82 c10 custom deluxe with a 305 came with one.
I've just only ever seen this truck with a single one. I've always seen dual saddle tanks on everything.
The 20 gallon saddle tank itself isn't rare. I think only short beds came with the 17 gallon saddle tanks.
My 73 has just a single 20 gallon saddle with the 350 engine and it's a pain having to fuel up so often; I can only imagine how irritating it would be with a big block. Well, I guess I know because I've only got the 1 tank I can select right now.
Since I've been driving the crew cab while the 73 has been down for the front end rebuild, I've found that the 4l80e and Magnum setup have dropped my MPG. Up until the past week I'd just been driving the crew cab occasionally. I thought something was wrong with the fuel tanks because it seemed like I was needed to fuel up sooner than I thought. After driving it consistently and tracking mileage I figured out it's because I've lost about 2 to 3 MPG.
The overdrive on the 4l80e isn't as much reduction as the 700r4 I was running. OD on the 4l80e is 0.75 and the 700r4 is 0.696. I noticed the difference right away just driving the truck. I rather be running closer to 2000RPM at 65 but instead it's closer to 2500. Plus there's a lot more drivetrain mass between the transmission and Magnum setup. I was getting around 10 for my typical driving and now it's about 7.5mpg.
So I'm thinking I may look at regearing. I figure the 454 in there now doesn't produce anything but more noise over 3500RPM. I put 5.13 gears in to help with the 350 and standard tcase setup on the trail, but now with the Magnum that's not such a concern. I've also noticed with towing the camper, a little bit higher axle gear would help get the power band where it needs to be a certain speeds. I'm probably going to drop all the way down to 4.56:1 in the axles.
My 73 has just a single 20 gallon saddle with the 350 engine and it's a pain having to fuel up so often; I can only imagine how irritating it would be with a big block. Well, I guess I know because I've only got the 1 tank I can select right now.
Since I've been driving the crew cab while the 73 has been down for the front end rebuild, I've found that the 4l80e and Magnum setup have dropped my MPG. Up until the past week I'd just been driving the crew cab occasionally. I thought something was wrong with the fuel tanks because it seemed like I was needed to fuel up sooner than I thought. After driving it consistently and tracking mileage I figured out it's because I've lost about 2 to 3 MPG.
The overdrive on the 4l80e isn't as much reduction as the 700r4 I was running. OD on the 4l80e is 0.75 and the 700r4 is 0.696. I noticed the difference right away just driving the truck. I rather be running closer to 2000RPM at 65 but instead it's closer to 2500. Plus there's a lot more drivetrain mass between the transmission and Magnum setup. I was getting around 10 for my typical driving and now it's about 7.5mpg.
So I'm thinking I may look at regearing. I figure the 454 in there now doesn't produce anything but more noise over 3500RPM. I put 5.13 gears in to help with the 350 and standard tcase setup on the trail, but now with the Magnum that's not such a concern. I've also noticed with towing the camper, a little bit higher axle gear would help get the power band where it needs to be a certain speeds. I'm probably going to drop all the way down to 4.56:1 in the axles.
Well you drive Dimples so that would work..........
And I have dimpled saddle tanks....
Back up and running on 2 tanks.
I picked up a Carling Rotary switch that is DPDT.
After looking over the the wiring diagram for the tank selector switch, I realized it was a good thing I got a DP switch.
For whatever reason it looks like they use the OFF tank lead as a ground for the selector valve. There are 2 wires that run from the switch to the valve and they are both used; either for power or ground. So one side of the switch is for ground and the other side for power; just have to flip the wires. Here's the pin out I used:
The 7, 8, and 10 terminals are for the red and green indicator lights.
I removed the terminals from the melted housing and put them in some I have that work with the same terminals.
Unfortunately, I didn't have a 4-port plug so I had to use a 3 and a 1. I put the power in wire on the single plug. Then I just made pigtails between these plugs and the switch. The Carling switch fit in the hole I already had.
The rotary switch is an ON-OFF-ON so I like that I can put it in the middle position and maybe confuse a would be truck thief. I also like that now when I want the left tank the switch points left and when I want the right tank it points right.
The only thing I think I will change is to add a fuse in the wire that provides power to each tank. The switch is rated for 20 amps. The pump is supposed to pull around 11-12 amps at 60psi. So if everything is functioning properly, there shouldn't be a load problem.
I picked up a Carling Rotary switch that is DPDT.
After looking over the the wiring diagram for the tank selector switch, I realized it was a good thing I got a DP switch.
For whatever reason it looks like they use the OFF tank lead as a ground for the selector valve. There are 2 wires that run from the switch to the valve and they are both used; either for power or ground. So one side of the switch is for ground and the other side for power; just have to flip the wires. Here's the pin out I used:
The 7, 8, and 10 terminals are for the red and green indicator lights.
I removed the terminals from the melted housing and put them in some I have that work with the same terminals.
Unfortunately, I didn't have a 4-port plug so I had to use a 3 and a 1. I put the power in wire on the single plug. Then I just made pigtails between these plugs and the switch. The Carling switch fit in the hole I already had.
The rotary switch is an ON-OFF-ON so I like that I can put it in the middle position and maybe confuse a would be truck thief. I also like that now when I want the left tank the switch points left and when I want the right tank it points right.
The only thing I think I will change is to add a fuse in the wire that provides power to each tank. The switch is rated for 20 amps. The pump is supposed to pull around 11-12 amps at 60psi. So if everything is functioning properly, there shouldn't be a load problem.
Figured out a side benefit of the indicator light on the new switch. If power to the pump goes off, so does the light. I had the terminals wrong and the lights weren't coming on. After swapping them, I tested it without starting the truck. The light was on, then went off. When I started the truck it came back on. I realized it went off because the fuel prime stopped. So now I'll know if I have power coming from the Sniper system for the fuel pumps.
As indicated, the wiring for the indicator lights is backwards from what you'd expect.
Terminals 8 & 10 power the indicator lights. One would hope terminal 8 would go with terminal 1, but it does not. When terminal 1 is energized, the terminal 10 indicator light is the correct power lead. So I have gray and tan wires crossing 3 ways on this switch. FWIW terminal 7 is the ground for both lights.
As indicated, the wiring for the indicator lights is backwards from what you'd expect.
Terminals 8 & 10 power the indicator lights. One would hope terminal 8 would go with terminal 1, but it does not. When terminal 1 is energized, the terminal 10 indicator light is the correct power lead. So I have gray and tan wires crossing 3 ways on this switch. FWIW terminal 7 is the ground for both lights.
I had a problem with my crew cab saddle tanks not working on the left side. I found out that a PO put a wire crimp in the tan wire that is the temporary hot until the solenoid takes over as the hot for which ever tank is selected. The wire crimp was bad, and causing to much resistance. This also caused to much heat build up, and burned the tank selector rocker switch. I replaced the wire crimp, and the rocker switch, and that fixed the problem.
Interesting.
When I got this truck, only 1 tank was working but I can't remember which; it's probably somewhere in this thread. I'll have to look at it and see if the inoperable tank was the same tank that melted the switch. It's been running now for probably 6 years, but might be worthy of checking the wires further if it was the same tank.
When I got this truck, only 1 tank was working but I can't remember which; it's probably somewhere in this thread. I'll have to look at it and see if the inoperable tank was the same tank that melted the switch. It's been running now for probably 6 years, but might be worthy of checking the wires further if it was the same tank.
I have the electronic tank selector switch that 1988 to 1991 square body TBI pick-up trucks came with, and not the mechanical one that carbed trucks came with. From what I can tell there is a pink wire going to the tank selector rocker switch that is hot when the ignition is turned on. Then there is a tan wire that goes from the rocker switch to the fuel pump solenoid that provides a hot that engages the solenoid. When the solenoid engages it causes the tan wire circuit to go open, and completes the hot circuit coming from the battery/alt hot, which provides the power to the pumps while the engine is running. There are two more green wires coming from the rocker switch. one of those wires goes to the left tank, and the other to the right tank. Those are the ones that select which tank you want.
If you take out those 5:13 gears I would be interested in buying them for my 1991 V3500 crew cab.
I'll keep that in mind.
