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Unread 08-25-2013, 07:32 PM   #1
HeathFinnie
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1976 CJ5 
 
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Wiring the gas tank - questions

So I want to finally wire the gas tank on my 76 CJ5. Any idea which gauge wire was used originally? Was it 16?

I'm hoping I don't need to drop the tank completely to get it set up.

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Unread 08-25-2013, 07:46 PM   #2
LeePrather
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By wire, you mean? Sending unit replacement? Fuel line replacement? Just replace the sending unit wire? You will drop the tank to do any of the above. It's really fun too...
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Unread 08-25-2013, 08:55 PM   #3
BagusJeep
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From the rear connector (which is near the instrument panel) backwards it is in 16 gauge pink. There is then a connector near the tank sender and it goes into 16 gauge white for the final connection.

The sender grounds through the tank, a couple of rusty bolts back to the frame and tub and eventually a grubby earth strap in the engine compartment to the battery. If you are going to expose it a seperate ground attached to the sender is a good idea, 16 gauge black. As a minimum attach the other end to the frame, though ideally you could install a seperate ground system back to the battery through copper wires.
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Unread 08-26-2013, 04:37 AM   #4
HeathFinnie
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Thanks, yes just the wire from the gauge to the sending unit. The PO never connected it up when redid his frame off build.
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Unread 08-26-2013, 04:47 AM   #5
LeePrather
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A piece of advice: don't bolt that tank back up until you know it works. If they didn't hook it up, you might have a bad sending unit in the tank...there are 4 bolts under the back of the skid plate and 2 under the front. I wouldn't undo the front 2. I would try to just drop the back. It may not be easy to get everything lined back up if you pull the tank down all the way. Also, you need the gas tank empty or close to it...go ahead and replace your rubber fuel lines while you are under there.
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Unread 08-26-2013, 08:44 AM   #6
HeathFinnie
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Quote:
Originally Posted by LeePrather
A piece of advice: don't bolt that tank back up until you know it works. If they didn't hook it up, you might have a bad sending unit in the tank...there are 4 bolts under the back of the skid plate and 2 under the front. I wouldn't undo the front 2. I would try to just drop the back. It may not be easy to get everything lined back up if you pull the tank down all the way. Also, you need the gas tank empty or close to it...go ahead and replace your rubber fuel lines while you are under there.
I think (from pictures I saw) that the sender is towards the drivers front of the tank if I'm not mistaken on a 76? Although this jeep has had a lot of changes so they might have switched the tank at some point too.
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Unread 08-26-2013, 08:49 AM   #7
CJ7ROB
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Quote:
Originally Posted by LeePrather View Post
A piece of advice: don't bolt that tank back up until you know it works. If they didn't hook it up, you might have a bad sending unit in the tank...there are 4 bolts under the back of the skid plate and 2 under the front. I wouldn't undo the front 2. I would try to just drop the back. It may not be easy to get everything lined back up if you pull the tank down all the way. Also, you need the gas tank empty or close to it...go ahead and replace your rubber fuel lines while you are under there.
Good info, not to jack the thread but on an '86 with the poly tank & skid, would it be pretty much the same deal? Also I have new filler hoses, can I just leave them attached when I drop the tank some? thx
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Unread 08-26-2013, 08:54 AM   #8
LeePrather
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Quote:
Originally Posted by HeathFinnie

I think (from pictures I saw) that the sender is towards the drivers front of the tank if I'm not mistaken on a 76? Although this jeep has had a lot of changes so they might have switched the tank at some point too.
It is toward the front and you can get in there comfortably with your arm to access the wires if you just drop the front 4 bolts (plus the 5th in the middle that is the tank strap). You will have 2 fuel hoses, 1 ground wire and 1 sender wire. If you just replace the wire, you don't have to drop the tank completely, but that's pretty optimistic with these cheap sending units. I am dropping my tank today to install the last of my vdo senders...
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Unread 08-26-2013, 08:57 AM   #9
LeePrather
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Quote:
Originally Posted by CJ7ROB

Good info, not to jack the thread but on an '86 with the poly tank & skid, would it be pretty much the same deal? Also I have new filler hoses, can I just leave them attached when I drop the tank some? thx
My guess is yes...mine is a 78 and I'm pretty sure everything from 76-86 is roughly the same with minor changes to shape and design
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Unread 08-26-2013, 03:00 PM   #10
james04si
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My suggestion is to just drop the tank. You will have way more room to work. I've had mine down a good 10x dealing with cheap senders and hoses through the years. Mine has always had a ground connected from a spade connector on the sender to the frame and I have no idea what color the original wire was since the po didn't have mine even wired much less a gage in the dash. I used 16ga wire and have had no issues with the wire in the past 15 years.

If you need a new sender unit it will probably come with a cheap plastic float. From experience chunk the float and use the original or get a float for an older ford which are brass. I would not have had to drop my tank so many times if I had done this the first time.
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Unread 09-22-2013, 01:39 PM   #11
HeathFinnie
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If I take and do a continuity test on the gas gauge itself, I'm getting continuity from one post of the gauge to the other. I'm guessing that is not correct? I also was getting 12V at the end of the sending wire by the tank…

(edit) after some research I've discovered that this might be the way it's supposed to work. So if thats the case it's either the gauge or the sending unit (my grounds seem good).

If I take the side of the gauge that goes to the sending unit and ground it to the dash nothing seems to happen...
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