Adding in-tank fuel pump to CJ sending unit - JeepForum.com

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post #1 of 36 Old 08-23-2014, 11:10 AM Thread Starter
Dborns
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Adding in-tank fuel pump to CJ sending unit

I asked this in another thread I had on some tank issues, but hadn't had a response and can't find much on if this can be done on the net.

The pic is of an issue I got into on the sending unit/ fuel pump. I ordered what was supposed to be the Ford frame mounted pump awhile back, but when I pulled it out today found that I have an in-tank pump. I'm determined to make this work if I can since I've spent the money and can't return the pump. Looking at the sending unit and pump, my plan was to cut the pick-up tube on the sending unit and take off the same length as the pump. Then flare the cut end of the tube and connect that end to the pump with some rubber hose. Basically the pump would take the place of the cut length of hardline I took off the sending unit. Is that something that would work? If it does, my other question is how do I wire it correctly down through the sending unit?

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post #2 of 36 Old 08-23-2014, 11:16 AM
Mike Romain
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I would try it. You will need the sock filter on the end. Big trick is to find rubber that won't get destroyed by ethanol. I would be thinking on trying to solder the tubes maybe. The upper tube may be the ground also.

Mike
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post #3 of 36 Old 08-23-2014, 11:26 AM
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post #4 of 36 Old 08-23-2014, 11:31 AM Thread Starter
Dborns
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Quote:
You will need the sock filter on the end
The new pump did come with a sock filter that slips on the end.

Quote:
Big trick is to find rubber that won't get destroyed by ethanol
I threw that question out in the other thread, but actually about the line clamps I would have to use to connect the short rubber line in between the pickup tube and the fuel pump port, (asking if gasoline would degrade those clamps over time). My first thought was if gas would eat that rubber fuel line, but how does that happen if that's what fuel lines are made of anyway?

Quote:
I would be thinking on trying to solder the tubes maybe
I can't solder them together because the port on the pump is plastic.

Quote:
The upper tube may be the ground also
I think youre correct, because theres a wire that goes through the top of the sending unit attached to the grounding bolt. I can't remember if its connected to the return tube or not, but I'm sure that's correct.
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post #5 of 36 Old 08-23-2014, 11:33 AM Thread Starter
Dborns
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Wow, that's exactly what I needed Hack. How do I go about wiring it? If its a Ford pump, do I just need a Ford jumper, or did you make that?

Thanks
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post #6 of 36 Old 08-23-2014, 05:25 PM
HackFabrication
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It's a 255 lph Walbro pump.
The tubing soldered onto the pump is from a Mustang setup.
Wiring is stock for the pump.
I purchased the wiring pigtail, filter sock, and EFI tubing from an online company that I no longer have the link for.
The wiring is routed out the fuel return port. It's just a simple +/- connection.
One of the downsides is that the fuel level sender had to be disconnected from it in order to ease insertion in the tank, then re-assembled.

It worked fine for the time I had it installed, however, I have decided to go with an external fuel pump.

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post #7 of 36 Old 08-23-2014, 05:46 PM
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Not sure about the 15 gal tank, but the deepest part of the 20 gal tank is not directly below the sending unit/pickup hole on the top of the tank.

To get the pickup to the deepest part, you'll need to bend the down tube, so that the pump is angled towards the front. An aftermarket pickup (without the pump) is a good model for positioning the pickup.

The top and body of the pickup assembly is will be grounded, so the pump power needs to be isolated as it passes through.

I also like to use the solid style float as shown in Hack's setup. I've had both the brass and plastic style leak and flood.

Good Luck

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post #8 of 36 Old 08-23-2014, 07:02 PM
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It's really not too bad. I used a GM pump,thus I used the bulkhead connector from a GM sending unit. 2 years 10,000 miles and no issues at all. I duplicated the factory GM unit as closely as possible,to go along with my tbi setup.

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post #9 of 36 Old 08-23-2014, 08:53 PM
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Quote:
Originally Posted by HackFabrication View Post
This is pretty much how I did my in-tank pump on my 75 CJ5. I used a pump from a 91 chevy truck. I had to cut the old tube off and add an insulated wire fitting.. I did add a stiffener across the pipe and pump, securing it with hose clamps and safety wired tightly.. The pump kit I bought had pretty much everything I needed, including the correct in-tank fuel line to connect the pump to the stem..

Here's a word of caution. There is no silicon gasket material made that will stand up to gas.. But I did find some stuff called Seal All [$3.99 at HD] that is extremely fuel resistant. I used this to help seal the fitting and hole I made for the power wire to the pump..

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post #10 of 36 Old 08-24-2014, 03:42 AM
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Quote:
Originally Posted by zillla View Post
I did add a stiffener across the pipe and pump, securing it with hose clamps and safety wired tightly..
This is also a good idea. A simple strip of steel, with a couple of bends, and two hose clamps would suffice. Or get fancy and solder it to the tube, hose clamp it to the pump (for removal).

I considered epoxy to seal the wires, as there would be little need to remove the wires since the pump would unplug from the pigtail.


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post #11 of 36 Old 08-24-2014, 08:21 AM Thread Starter
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Quote:
This is also a good idea. A simple strip of steel, with a couple of bends, and two hose clamps would suffice
I think I'm following you all now. If I cut the pickup tube, and clamp the pump to the end of the tube with a short piece of rubber line, eventually movement may cause that rubber line to tear or break, so a piece of steel between the upper pickup tube and pump acts as a support. Thats not to difficult.

I looked at other pumps on ebay and rockauto, and most come with a pigtail which mine didn't. I may have to look at what years the pump I have are installed in and try to pull one from a junkyard.
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post #12 of 36 Old 08-24-2014, 08:51 AM
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I am really wondering if any of the rubber so called gas line is compatible with ethanol. I was cleaning out the shed yesterday and found some recently purchased rubber gas line I used for a generator last year and all of it has gone real hard and brittle except the end that is still in gas. It is super soft.

I also have two boat style primer bulbs less than 3 years old and they have gone rock hard. Total trash.

Well I guess if you end up with real low fuel pressure in the future you will know where to look first....

Mike
86/00 CJ7 Laredo, 33x9.5 BFG AT's, 'glass nose to tail in '00, 'New' frame,wires and plumbing in '09. Carter BBD Carbed 4.0 HO in '10.
89 YJ Renegade. BBD Carbed 4.0 HO. Locked front and rear with 33x9.5 BFG AT's
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post #13 of 36 Old 08-24-2014, 11:11 AM
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Quote:
Originally Posted by Mike Romain View Post
I am really wondering if any of the rubber so called gas line is compatible with ethanol. I was cleaning out the shed yesterday and found some recently purchased rubber gas line I used for a generator last year and all of it has gone real hard and brittle except the end that is still in gas. It is super soft.

I also have two boat style primer bulbs less than 3 years old and they have gone rock hard. Total trash.

Well I guess if you end up with real low fuel pressure in the future you will know where to look first....
There is a ton of junk rubber out there. I will not even buy regular fuel line anymore on the Weatherhead FI rated stuff. Weatherhead is good stuff but I cannot say that it is rated for ethanol. Even if the liner is the exterior is likely formulated for UV/ozone resistance and may not handle ethanol.
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post #14 of 36 Old 08-24-2014, 11:21 AM
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I used what came on my original GM pump assembly.....I wonder how that's going to hold up.....hmm

Dave in Muskegon using JeepForum
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post #15 of 36 Old 08-24-2014, 11:23 AM
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alternative to rubber

How about this stuff, guys?

http://www.goodyearep.com/ProductsDetail.aspx?id=17700

Specs say it'll handle just about any fuel situation. Even if pricey, you won't need much.
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