grumpin Posted October 15, 2018 Share Posted October 15, 2018 I've had a problem getting all the fuel out of the rear tank. One thing I found was the oil pressure switch for the fuel pump had a bad connector. I have not been able to find one yet, so I butt connected the wires together, that affected both tanks. At first the rear tank seemed to consistently run down to about 2 gallons of fuel remaining, per the fill up which would take around 17 gallons. On a recent trip I was running on the rear tank and stopped and got gas and went to the restroom. As I drove from the station it died, I tried it again and it died. Tank was full. I watched the odometer and drove ten miles at highway speeds. Switched to the rear tank and drove the rest of the way home around 170-175 miles. The next day I was able to drive it for 20 miles or so and it died, waited a bit and it died. This morning I switched to the rear tank before I started it, I have not fueled it yet, and was able to drive 5-6 miles and it died, I pulled over and pulled the gas cap and I can hear the pump running. Tried it a couple of more times and it died. Drove home, parked and switched to the rear tank and it sat there happily idling. Pulled the gas cap and listened. Let it run for maybe 15 minutes and it was fine and the pump sounded consistent. By my estimate I have 1-2 gallons of gas in there. The only thing I'm seeing different between the two tanks is the pump. I have drove it with the gas cap loose. Looking for ideas from this knowledge laden forum! Link to comment Share on other sites More sharing options...
85lebaront2 Posted October 15, 2018 Share Posted October 15, 2018 It could be several items. The "sock" on the pump may be bad. the hose from the pump to the hanger could be leaking. How old is the pump? OEM or replacement? I went through a royal PITA when I had to replace the front one on Darth. All except Pep Boys wanted to sell me an EFI pump, they had Borg-Warner pumps and it was the exact match (this was in 1994). Other question, is the 6 port motor driven valve going completely to the rear tank and powering the pump reliably? On the switch. Chrysler used a switch for the electric chokes on the 2.2L carbureted engines that has two 1/4" flat terminals, same as their A/C low pressure switch. One of those, and I think I have several spare molded plugs for the A/C switches. Link to comment Share on other sites More sharing options...
grumpin Posted October 16, 2018 Author Share Posted October 16, 2018 It could be several items. The "sock" on the pump may be bad. the hose from the pump to the hanger could be leaking. How old is the pump? OEM or replacement? I went through a royal PITA when I had to replace the front one on Darth. All except Pep Boys wanted to sell me an EFI pump, they had Borg-Warner pumps and it was the exact match (this was in 1994). Other question, is the 6 port motor driven valve going completely to the rear tank and powering the pump reliably? On the switch. Chrysler used a switch for the electric chokes on the 2.2L carbureted engines that has two 1/4" flat terminals, same as their A/C low pressure switch. One of those, and I think I have several spare molded plugs for the A/C switches. 85lebaront2, I have thought the sock or lines in the sending/pump unit could be the culprit. Also the 6 port valve, I guess I thought since it defers to the rear tank that that "should" be OK. The way I understand they usually fail is feeding the opposite tank you are on. I don't know if the pump is OEM or not. Same pump since I got the truck a couple of years ago is all I know. Thought I would check before I get the tank pulled. I decided I'm not going to do it in my gravel driveway! If you want to part with one of those molded plugs I would be interested in one. Thanks for the info.! Link to comment Share on other sites More sharing options...
85lebaront2 Posted October 16, 2018 Share Posted October 16, 2018 85lebaront2, I have thought the sock or lines in the sending/pump unit could be the culprit. Also the 6 port valve, I guess I thought since it defers to the rear tank that that "should" be OK. The way I understand they usually fail is feeding the opposite tank you are on. I don't know if the pump is OEM or not. Same pump since I got the truck a couple of years ago is all I know. Thought I would check before I get the tank pulled. I decided I'm not going to do it in my gravel driveway! If you want to part with one of those molded plugs I would be interested in one. Thanks for the info.! On the 1986 system, the 6 port valve does not have a "default" position, it stays where it was set until it receives power through the tank selector switch. I may even still have the switch from Darth since he is now MAF/SEFI and is using the 1990 pump system and 1996 gauges. Link to comment Share on other sites More sharing options...
grumpin Posted October 16, 2018 Author Share Posted October 16, 2018 On the 1986 system, the 6 port valve does not have a "default" position, it stays where it was set until it receives power through the tank selector switch. I may even still have the switch from Darth since he is now MAF/SEFI and is using the 1990 pump system and 1996 gauges. Oh OK, I assumed it had to be powered out of the rear position. Good to know. Link to comment Share on other sites More sharing options...
grumpin Posted October 18, 2018 Author Share Posted October 18, 2018 On the 1986 system, the 6 port valve does not have a "default" position, it stays where it was set until it receives power through the tank selector switch. I may even still have the switch from Darth since he is now MAF/SEFI and is using the 1990 pump system and 1996 gauges. Oh OK, I assumed it had to be powered out of the rear position. Good to know. I finally got the pump to fail. It is loud too. I can hear it from the drivers seat with the door open and the fuel cap off and the engine running. The front one I can barely hear with the cap off and my ear next to the filler with the engine running. Going to a shop next Tuesday, quoted me $265 for parts and labor. Also 85lebaron, on the connector, I don't think a 1/4 inch type connector will work, unless I misunderstood you. Here is a picture of the connector. Link to comment Share on other sites More sharing options...
85lebaront2 Posted October 19, 2018 Share Posted October 19, 2018 I finally got the pump to fail. It is loud too. I can hear it from the drivers seat with the door open and the fuel cap off and the engine running. The front one I can barely hear with the cap off and my ear next to the filler with the engine running. Going to a shop next Tuesday, quoted me $265 for parts and labor. Also 85lebaron, on the connector, I don't think a 1/4 inch type connector will work, unless I misunderstood you. Here is a picture of the connector. I was talking about using the Chrysler switch if your switch was bad. Link to comment Share on other sites More sharing options...
grumpin Posted October 19, 2018 Author Share Posted October 19, 2018 I was talking about using the Chrysler switch if your switch was bad. Ok, I misunderstood. Thanks! Link to comment Share on other sites More sharing options...
grumpin Posted October 23, 2018 Author Share Posted October 23, 2018 I was talking about using the Chrysler switch if your switch was bad. Ok, I misunderstood. Thanks! Well, the shop could not get the sending unit out, the lock ring is rusted to the tank. I wasn't surprised, they're getting a new tank, sending unit and all. Estimate is $550 or so. I'll just be glad to have this behind me. Link to comment Share on other sites More sharing options...
Gary Lewis Posted October 23, 2018 Share Posted October 23, 2018 Well, the shop could not get the sending unit out, the lock ring is rusted to the tank. I wasn't surprised, they're getting a new tank, sending unit and all. Estimate is $550 or so. I'll just be glad to have this behind me. Will that be a 19, 32, or 38 gallon tank? The 19 would be stock, 32 would be a Bronco, and 38 would be an aftermarket that will fit. Link to comment Share on other sites More sharing options...
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