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Fuel Pump

Posted: Sun Dec 30, 2018 5:48 pm
by Carl
What would cause the fuel to drain out of the fuel filter when the engine is not running ? I have checked all over and cannot find any leaks anywhere. I installed a new fuel pump and it does the same thing. If you put some fuel into the carb and get the engine to run it will fill the filter and will run good but after an hour or so the filter will be empty again....I have a 89 Jeep Rangler that has the same problem....any help you can give this old guy will be appreciated...Thanks

Re: Fuel Pump

Posted: Mon Dec 31, 2018 8:04 am
by Carl
I meant to say that after running the engine for awhile and shutting it off, after an hour or so the fuel filter will be empty....thanks

Re: Fuel Pump

Posted: Mon Dec 31, 2018 9:34 am
by Stan
Does your Jeep have a carb or fuel injection ?
The similar problem I have and have been reading others with carburetors are having is due to fuel evaporating from the fuel bowls due to engine heat and the "new " blend of gasoline.
One of my Broncos is worse than the other it'll have that issue after a day or two or three. The other isn't quite as bad and takes 3 -4 days or longer . It runs cooler engine temps and under hood temps though .
I'm not convinced that's the issue but seems to be the general consensus .

Re: Fuel Pump

Posted: Mon Dec 31, 2018 5:45 pm
by Carl
Both the Bronco and the Jeep have carbs. It seems that the bowl will be empty faster than that. It will only

take less than 1 day for the Bronco to drain and maybe 2 days for the Jeep to drain...This is a real bummer as the vehicle will not start unless you put some fuel into the carb or use starting fluid and get it to turn over enough to fill the filter...…...I really need to get this fixed...Thanks Stan

Re: Fuel Pump

Posted: Tue Jan 01, 2019 1:44 pm
by Stan
I usually turn the key and crank the motor over for 10 seconds or so to refill the fuel bowl then go to the standard starting procedure . If it doesn't start then I crank it over for another 5-10 seconds.
I've been thinking of installing an electric fuel pump and bypass line just for starting and refilling bowl ; take some of the wear and stress off of starter and etc.
One of the throttle body fuel injection systems would also cure the problem.

Re: Fuel Pump

Posted: Thu Jan 03, 2019 12:04 am
by DirtDonk
Seems you could have two things going on (maybe more, but I'm not aware of them) like a little bit of it draining back into the tank because the check valve in the pump is not working 100% and the other would be some siphoning action sucking some of it into the engine while sitting.
Oh, and I guess the third thing would be at least some bit of evaporation.

Modern fuels are more funny that way, and maybe the winter blends are even more so perhaps?
All I know is that we have a lot of failures in fuel system components on our older vehicles due to "unforseen" difficulties with new fuel compatibility.
Especially if your rig sits more often than it drives. Things like fuel pumps don't like to sit. Especially the Chinese crap ones!


Re: Fuel Pump

Posted: Sun Jan 13, 2019 8:43 am
by Carl
Thanks Paul....I think I will try a fuel shut off valve below the fuel filter . I don't drive this Bronco much and it is always in the garage so I don't mind opening the hood and switch the valve. I may even install one between the fuel pump and the fuel tank. It doesn't take much to switch them as they will be easy to get to...Hope this works !!! Thanks again ...this is a great site to get help !!

Re: Fuel Pump

Posted: Thu Mar 28, 2019 4:28 pm
by Carl
What is a good electric fuel pump for a 1970 302 Bronco that is easy to install and not real expensive ? Thanks

Re: Fuel Pump

Posted: Thu Mar 28, 2019 7:13 pm
by DirtDonk
Well, for a carburetor everyone that uses them seems to think the Carter 4050 (I think that's the number?) is the best pump around.
But I don't think they're cheap compared to the typical parts store cheapies.

That said, I'm pretty sure that some of those same cheapies are pretty good. Some are crap too though, so it's a hard choice.
Believe it or not we've had great luck at WH with both the inexpensive Mr Gasket pumps and the more expensive Edelbrock. Both fall into that compact low pressure category. Very easy to mount and plumb in.

For a single tank just mount it on the frame or crossmember near the fuel pickup from your tank. For dual tanks with the selector valve, you need to put it after the valve or you need two pumps.
After the valve is still doable, but the point is you don't want to run most electric pumps up near the engine because they push much more efficiently than they pull. So if you use them as a puller pump you can have problems especially when it's hot.
Some people get away with it, but most don't. So better to mount it as close to the tank(s) as possible.


Re: Fuel Pump

Posted: Fri Mar 29, 2019 4:12 pm
by Carl
Thanks Paul Can you let me know where I can get either the Mr Gasket or the Edelbrock and what model to get for the 302 Bronco. Also said before I am now 80 years young and would really like something that I could install easy and hope they have some good directions to work with.

Re: Fuel Pump

Posted: Mon Apr 01, 2019 9:21 am
I always thought the long crank was by design to build oil pressure before it started ;)

Re: Fuel Pump

Posted: Thu Apr 04, 2019 12:52 pm
by DirtDonk
I can work with that Shawn. Gives you the warm and fuzzies that they were really using their heads back then and had only our safety and well being in mind.

Sorry Carl, didn't see your question before. And I don't see a quote button anymore?
Anyway, Should be able to get the Mr Gasket pumps just about anywhere I would think. We carry them as well and would be happy to send you one of course!

The Carter was the wrong number. I think it's a P4070 instead. Probably any auto parts store or Summit Racing. Jegs too, which is closer to you I believe.
I doubt they have very detailed instructions, but both do come with at least some. I haven't looked at mine yet, but will check it out as soon as I have some time. Probably very generic in nature, but in fact they are pretty basic. Insert in the fuel line between engine and tank and call it a day.
Well, maybe not, since it still involves climbing(?) under the truck to find a good place to mount it.

Nobody is going to have a Bronco-specific mounting instruction that I know of. Maybe we should, but every Bronco is different so often than what works for one might not work for the next.
The frame rail on the driver's side ahead of the rear tank is usually the easiest spot. You just have to work around the selector valve if you have two tanks.
For that I would still put it on a low spot of the frame more towards the rear tank, then run the "outlet" of the tank selector valve back to the pump's inlet and then run from the pump to the engine.
This gives you more options and keeps the pump low and to the rear. The way the valve is placed on the driver's floor makes it look easier to put the pump more up front. But electric pumps definitely work more efficiently as "pusher" pumps and don't like to be mounted up towards the engine compartment in all cases.

And I would not mount it to the body if I had a choice. More potential for noise if you do.
But if you have to use the body, use a very stiff and stable panel and insulate the pump mounts somehow to reduce the vibration.
In fact, insulate/isolate the mounts any way you can no matter where you mount. Just a better practice in general.

good luck


Re: Fuel Pump

Posted: Thu Apr 04, 2019 4:22 pm
by Carl
Thanks Paul ….. That helps a lot..... Another question is where do you hook up the wiring and do you just cut the fuel line to hook to the pump or what . Let me know what you need to send me one of the Mr Gasket pumps. I have PayPal or credit card also I guess that would need a close off plate for the old pump wouldn't I ?

Re: Fuel Pump

Posted: Thu Apr 04, 2019 11:06 pm
by DirtDonk
Thanks Carl. And yes to the block-off plate. And yes (with riders, caveats, chicken little warnings and much hand-wringing) to the cutting and inserting of the pump into the fuel line. But...

We have the block-off plates as our #8037. The pump is the #8021 and both can be seen here: ... =fuel+pump

For the fuel line, you likely want to replace any rubber sections if the rubber is old. And most (if not all) EB's came from the factory with at least some hard-ish plastic fuel line runs, with rubber fuel hose as the interface between the valve, original pump, and the feed line/sending unit. It's also fairly tightly run, so not a lot of slop letting you easily mount a pump without adding some additional hose.
Which you would want to do anyway, if you have two tanks and want to put the pump farther rearward like discussed. So you may need (most likely will need) some additional 5/16" or 3/8" good quality fuel line. You don't need 100psi rated EFI line, but don't go for the cheapest stuff offered at most parts stores either, as it's likely not going to last very long. Sadly just like so many of the things we get these days...
You'll need to check your own fuel line sizes to be sure too. All EB's were 5/16" between the mechanical pump and the carburetor, but many (including my '71) used 3/8" line between the tanks and the pump.
Many other people have reported finding 5/16" line under their trucks too however, so you do need to check what you have.

If you have a standard sending unit with good sock filter still in use, you probably do not need a pre-pump filter in addition to it. Just run the pump and the filter that Ford uses on the carb. But it doesn't actually hurt if you want to add a good filter either.
Too many filters can impede flow, but I don't think you're worried about that at this level. Another one of the "up to you" decisions.

Now, for the wiring...
You do not run it directly from the ignition switch or existing wire directly. You want to use a relay to make sure you get full power to the pump and do not put much additional load on the switch. Pumps like these don't actually draw that much current, but every time you add something else to the stock ignition switch you get closer and closer to it's happy-place limit.
A relay and some 14ga wire, plus an inline fuse and you're good to go. Well, almost.
With electric pumps you really do want at least a cutoff switch tied into the oil pressure so that when the engine is turned off or dies, the pump will shut off no matter what else is going on.
An inertia switch isn't a bad idea either (in fact it's a great idea) but you can keep things simple for now if you want.

Are you familiar with general wiring stuff? And relays? If not let me know and we can run through what's what and how you'd want to utilize a relay.
Relay's are just "remote switches" basically, and use very little energy themselves. You want your trigger wire to be from one of the ignition switch's "ON" circuits and not one that has juice in ACC too. This way you can still listen to the radio or do whatever you need and not have the pump running when it's not needed.
Those would be either the Green w/red wire on the passenger side for the voltage regulator, or the Red w/green wire behind the engine for the ignition. My go-to is always the regulator wire though, so nothing else is attached to the ignition system unless that's your only choice.

Let me know if you have any other questions.
And thanks for using us. You can just call it in or run through the website if you prefer. We do take PayPal if that's your preferred method, but you definitely need to either call it in and they'll put you in touch with Dave (or maybe Brian too) specifically so they can run it through, or if you purchase online just put PayPal in the notes and someone will call, or e-mail you to get the particulars.
Otherwise credit card works too.

I'm not in the office much (and won't be tomorrow) so working through the system you'll get whoever's handy at that moment. I'll be in on Saturday, but the phones don't work on weekends anyway (thank goodness!) and nobody would have time to answer them if they did. It's our Annual Bronco Roundup this Saturday and I'm going to be hanging out in the parking lot with three or four hundred of my closest friends!

Good luck. And no problem asking questions along the way. Rather than through the website here though, if you're in need of an answer sooner you can use my e-mail. Or if you're actually in a hurry and I don't answer right away, the phone is the quickest.

Thanks again.


Re: Fuel Pump

Posted: Fri Apr 05, 2019 4:25 pm
by Carl
Thanks again Paul for all your help. I probably would replace the entire sending unit along with new fuel lines. All this will have to wait a little while as I have some health problems that I need to take care of first. This will give me some time to order all the parts I will need and have them ready when I am up to it. It seems like the biggest thing for me would be the electric hook up. I will let my son look at your reply and he will be more able to do this work for me ...Thanks again and I will keep you updated on this, you have put a lot of time on this and I really appreciate it...….Carl

Re: Fuel Pump

Posted: Fri Apr 05, 2019 7:36 pm
by DirtDonk
Sounds good. To that end I'll post some of the connections here and now so he can check them out when it's all ready, without having to wait for another reply.
This will deal only with the main relay/power connections to run the pump. Not the specific oil-pressure cutoff switch wiring. Probably have to work with the switch manufacturer's instructions on that if you use one.

Basically, what is known as a standard "Bosch type" relay, but also goes by other "type" names as well. The connections have an industry standard nomenclature and physical characteristics to keep things simple. The connections are either standard 1/4" wide male blade-type contacts, or many companies make a pre-wired base that it plugs into and all you do is connect the other end of the wires to their individual points.
The connections on the base of the relay work like this:

1. Pin #30 is power in from the battery and will ultimately power the pump. A single 14g wire directly to the battery positive, or the starter relay positive side, or whatever constant power source you decide on. Always hot, and not switched.
Here is usually the only other place you should add a fuse. Small blade type or glass fuse or whatever. Likely 15a is just right.

2. Pin #85 is ground and can have a short wire directly to the body if that's convenient. A small wire in the 18 to 20 gauge range is all that's needed for this low power segment.

3. Pin #86 is 12v switched power from your ignition switch's ON only wire. Here is where the old Green w/red from the voltage regulator can come in handy since it's one of only two wires that is hot in ON only and not also hot in ACC.

4. Pin #87 is power out to the load (in this case the pump). So this one should have 14g wire, like pin 30 has.

5. Pin #87A (if present) should be ignored for this application. It's hot when the key is off, vs hot with the key ON like pin 87 is. Just makes the relay useful for other types of circuits. Not all of these relays have the 87a pins, but more and more do as companies try to pare down their inventory.

Because the relay can be switched on/activated by controlling either #85 OR #86, a positive or a negative signal can trip the relay into closing the contact (remember the relay is only a "remote switch" that relay's the original switches commands to a more robust system. Hence the name relay.
If you choose to use an oil pressure cutoff switch, you could wire it into the ground circuit on #85 and that would cut off power to the pump as soon as oil pressure is lost.

At least some switches will work in this case. You actually want to be able to turn the pump on initially, just like modern computers do, so you don't want it off at first when there is no oil pressure because the engine has not been started yet. But I think there are simple switches that take care of that function for you somehow. Not sure how that works, but it should be pretty straightforward.
My only experiences with electric pumps have been either with no safety switch (PO installed) or with full computer control via a Ford or aftermarket EFI system.

Hope that helps. Good luck with the health stuff. I know working on the Bronco can help that, but only if it's fun and not to strenuous!