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PostPosted: Fri Sep 05, 2014 6:29 pm 
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I couldn't even tell you what fuel pump I'm on now, 6? Maybe 7 this year? First I thought it wasn't grounded well enough, then I thought maybe it wasn't getting a steady fuel supply, then I thought maybe it was a dirty tank, how about poor electrical current, maybe I got a couple junk pumps? No no no and no! I installed my current fuel pump about 6 weeks ago, and wired it all directly, or should I say as directly as possible to the battery made sure there was no kinks in my line and cleaned out my gas tank. I leave for Colorado just over a month ago and got back today. Before I left the truck ran perfect! I get back and try to start it today and the fuel pump is out again! They''ve all been Precision Pumps and seemed to last 3 to 4 weeks, but most the time its getting driven regularly. This time however, it was not driven while I was away and the thing still went out! I got 5 days to get this thing highway worthy for a long drive. Any ideas on why the POS keeps going out are appreciated, I'm starting to go crazy. What can cause a fuel pump to stop working while not working at all! By the way, all fuel pumps have still clicked and hummed like they were still working yet pull no gas through the carburetor. Please, please help. Thank you for anything!

Is it possible that gas is sitting in the fuel pump when it's not being used and rotting away some small piece in it cause it not to work? Just turned it on and disconnected it from the fuel filter and sure enough it's not sucking at all even tho it sounds like it's running right


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PostPosted: Fri Sep 05, 2014 7:59 pm 
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Is your tank vented correctly?

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PostPosted: Fri Sep 05, 2014 8:09 pm 
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I don't think the gas could be doing anything. There was concerns when they went to 10% ethanol in gasoline.It was only questionable on much older cars IIRC. Biodiesel and the new low sulfer diesel are a real problem on the diesel except the very newest ones. 85% ethanol gas would be a problem.

Regular gas will smell bad it it has become old in time.
Look for other problems. water in the fuel, I don't think that is your problem either. Some others will jump in and help.

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PostPosted: Fri Sep 05, 2014 8:10 pm 
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That's a great question. I don't know. I do know that when I hooked up my weber carb, there were two hoses running to the carburetor. I hooked the larger diameter hose to the new carb and plugged the smaller hose. But my fuel pump went out three times before I installed the Weber.


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PostPosted: Fri Sep 05, 2014 8:16 pm 
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Electric Fuel pumps want to push, not suck. That is why every new setup has the pump in the tank. How far is your electric pump from the tank. Does fuel run out of the hose before your pump?

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PostPosted: Fri Sep 05, 2014 8:25 pm 
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Is your plastic expansion tank still in the bed? Is the check and relief valve on the firewall still hooked up? I think your tank s not vented and the cap is a non vent cap causing the pump to run hard to overcome the non venting issue.

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PostPosted: Fri Sep 05, 2014 8:39 pm 
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Luvrv8 wrote:
Is your plastic expansion tank still in the bed? Is the check and relief valve on the firewall still hooked up? I think your tank s not vented and the cap is a non vent cap causing the pump to run hard to overcome the non venting issue.


Is the expansion tank still in the bed? Check and relief valve on the firewall still hooked up? I don't know! I'm not honestly sure what either of these things are... But if you think those things could be the problem, i definitely want to look in to them!

And i believe the fuel pump is in the stock location? About 2, maybe 2.5 feet from the fuel tank mounted to the frame. The inline filter is halfway between the tank and fuel pump.

I just can't figure out why, three times now, it's gone out after being parked. The fuel pump is failing when its not even being used... The other 3 times it has gone out while the vehicle was driving. Somethings not adding up.


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PostPosted: Fri Sep 05, 2014 9:16 pm 
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You could go with a vented fuel tank cap but you might smell fuel around the truck when it gets hot.

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PostPosted: Sat Sep 06, 2014 1:48 am 
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i went thru 6 of them in about a year and a half. replaced all the wires to the pump, put it on its own circuit with a relay and such. still burnt one out it must have to do with the location of the pump in relation to the tank
just upgraded to one of the mr gasket pumps which im sure is a clone of someone elses pump, its quieter and fits in the stock spot, it had a big foot plate that makes it fit in there funny but it fits. working so far under increased demand
I also bent my gas cap a bit on accident and that made it a bit of a vent so that may be helping

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PostPosted: Sat Sep 06, 2014 5:49 am 
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GOT IT! So the stock carburetor had to lines going to it, a smaller OD hose (return line) and a larger OD hose (fuel line). I had two fuel pumps fail with that carb set up.

I since put on a weber 32/36 dgev. I connected the fuel line to the weber and plugged the return line (like an idiot) because i didn't know what it actually did. Had four fuel pump failures with the weber on.

I woke up at 430am this morning, still pissed off and went out to tinker with the truck before i removed my 4,894th million fuel pump to go get a new one. I decided to remove the plug from the return line and blow as much air as i could muster through that line. At first i couldn't get any air through but i finally got to where a decent amount of air would travel through but it still feels very forced. Anyways. i climb down under the truck and look at the fuel filter and all of a sudden it's filling with gas again. I sit down in the truck. turned the key and it started immediately. Let it run for 10 minutes with no problem.

So, i had four failures with the return line plugged and two when the return line was hooked up correctly. I'm sure the return line is gunked up since it is 35 years old. What is my best plan of action from here? Fuel pressure regulator? Blow out the return line with a air compressor and hope for the best? Is there a way to actually vent the tank without a fuel pressure regulator? I love you all, so so much now. Going back to bed happy. Thanks.


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PostPosted: Sat Sep 06, 2014 6:02 am 
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I'm kind of hijacking my own thread here but i had another question that might be able to be resolved by the fuel pressure regulator as well but i'm not sure...

While the truck is in neutral or at idle, it misses out a lot, like 30-40 times a minute. Little spudders and toots, not really loud or bothersome, just kind of annoying and it doesn't sound healthy. Furthermore, when idling, if i give it a steady amount of gas then the RPM's come up with no hesitation, however if i mash the pedal to the floor it kills the engine immediately. I know it could be an air leak but i've checked pretty thoroughly with no luck of finding one. Anything else you could think of? Carb getting too much gas or not enough? Maybe too little or too much air? Trying to make her mechanically sound, we've got a 620 mile adventure coming up on Thursday, i'm gettin nervous!


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PostPosted: Sat Sep 06, 2014 6:42 am 
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Pumps do not like to push gas against a "dead" end. Most carbs will run 3 to 6 psi. If it can not pump because the float is not letting enough through because the carb is not using it. The gas flow through the pump is what cools it. I am not sure it that is what the return line lets excess fuel to the tank. A lot of fuel systems use a fuel pressure regulator. I do not know on a stock Luv any more.

Luvrv8 could chime in. My last stock Luv was 20 years ago till this last one.And what does the first problem with it? My electric fuel pump. On our Neon Race Car we run a regulator that returns extra fuel back to the tank.. Not the same, but make me go hummmm. If we did not run a regulator, our aftermarket fuel pump would burn up $125 + Not a big pump but nether is the engine and stock too..We set the PSI with a gauge off the fuel rail. I suppose to much fuel could cause the the carb to flood at a idle but when you increase the throttle the carb and engine can deal with the extra pressure-fuel flow.

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PostPosted: Sat Sep 06, 2014 7:30 am 
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To vent the tank drill a 1/8" (or even smaller) hole in the filler cap.
Your fuel pump may be providing too much fuel for the Weber causing the miss & sudden full throttle stumble. Stock fuel pump pressure is 4-7psi (the replacement pumps are likely the same range, the box should tell), Webers don't like more than 3psi, hence the recommendation of a fuel pressure regulator. A Holley #12-804 for about $40 will work, it's 1-4psi adjustable. Then re-tune the Weber to the best running conditions with the reduced pressure.

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PostPosted: Sat Sep 06, 2014 9:45 am 
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Great to hear you found the issue. I bet you will be fine now with the pump issue. Like others said, get the pressure down and it will run better. I have mentioned to several others about the fuel tank venting and most won't listen or even check. The fact that you actually didn't discard others theory's and actually looked into them is not the norm around here.

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PostPosted: Sat Sep 06, 2014 12:57 pm 
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Well the misses and sputters are definitely less than they were and if I mash on it now there's just a light dip before it revs, could probably chalk that up to me not being able to tune a carb. When I removed the old fuel pump it had built so much pressure in the tank that it drained the whole thing. First time i've ever seen it do that, what a mess.

I left the fuel return line open and blew it out the best I could. Opted for a 2-3.5psi Mr. Gasket fuel pump instead of spending the same price on a fuel pressure regulator for my 4-7psi pump. I wanted to install the fuel pressure regulator but it required 3/8s tubing and I couldn't gain access to the top of the gas tank so I opted for the smaller pump. Also I spent $15 on a vented gas cap. Here's to hoping it all works!


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PostPosted: Sat Sep 06, 2014 1:02 pm 
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Too late now, but the regulator doesn't have to be at the pump, it could be near the carb...

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PostPosted: Sat Sep 06, 2014 2:40 pm 
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mytmouz wrote:
Too late now, but the regulator doesn't have to be at the pump, it could be near the carb...

Correct- mount it to the passenger fender liner or firewall, used barbed 3/8" connectors screwed into the regulator and low pressure rubber fuel line w/clamps to connect to the supply line & carb, that way you have the assurance of full pressure flow from the pump to the regulator then the lowered pressure to the carb proper, plus the regulator is adjustable in case you need it to properly tune the carb/engine setup or if the pump begins to weaken over time. If your setup works that's fine, but there is a better way.

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PostPosted: Sat Sep 06, 2014 8:05 pm 
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There is a much easier way to solve your problem. As mentioned above those electric fuel pumps must move fuel in order to keep cool. The return line is a very important piece of the puzzle you didn't use. No fuel pressure regulator needed!!!!!!!!
The carb only needs 3-6 psi, but if the carb bowl is full then the fuel isn't moving and the fuel pump gets hot over heats thus stops working. All you need is to use the fuel return line and problem is solved. It is just this simple go to O'Reilly's and get a brass 3 way T. Get two 5/16" size by 1/4" thread brass nipples and one 3/16" size by 1/4" thread nipple. Will need a roll of thread sealing tape also. Once all this is purchased just lay the 3 way T on table place the two 5/16" at each end of T and wrap sealing tape around the threads not getting any extra over the holes and install them into the 3 way T. Once done wrap tape around 3/16 nipple and install into the top of 3 way T. The 3/16 nipple now goes back to return line and one end of 5/16" goes to main fuel delivery line while other end goes to carb. Problem solved!!!!! The fuel flows freely, pump remains cool, carb isn't over loaded by fuel pressure, and this also allows fuel tank not to create a vacuum because of a plugged off return line. Hope this helps.
Mike.


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PostPosted: Sat Sep 06, 2014 9:55 pm 
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I would just put a regulator in it on the fender well, keep the vent line open and call it good. I believe the fuel pump issues was the pump having to work overtime trying to pull fuel from a un vented tank. I have run my truck this way and never have had pump issues.

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PostPosted: Wed Sep 10, 2014 8:20 pm 
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Do you run a regulator? If so see if your pump is working to hard. Drive it for at least 30 mins. Then try to touch the pump for 10 secs. If you can't then its too hot. If you have a regulator with more then one outlet like I do. Take the fitting and solder it and drill a smaller hole and return it to the tank. That's what a mechanic told me.

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