EFI Fuel Pump - In-Tank or In-Line w/ accumulator?

[DanWheeler]

Need to decide on a fuel pump setup for an EFI conversion.

In-Tank pump:
PROS
- pump is protected and kept cool - long lasting
- single pump - less things to fail

CONS
- more likely to run dry when fuel level is low and vehicle is off camber
- may be more difficult to access the pump if it fails
- expense - I'll have to buy an expensive new tank that supports an in-tank pump


In-Line pumps w/ accumulator
PROS
- accumulator ensure fuel is always available until the very last drop even when the vehicle is off camber
- easy to change out in case of failure

CONS
- 2 pumps means 2 possibilities for failure

 

[gddyap]

I've read of guys putting in a door in the floor to access the top of the fuel tank to get to the pump. Also, it's a good idea to put some sort of baffling inside the pump either around the pickup or pump to help with sloshing and off-camber. I have in-tank for my '73 and will likely do the same with my '66 when I do the swap.

 

[DanWheeler]

also - if I were to go with inline pumps and accumulator, does anyone have part numbers for Ford high and low pressure pumps that would likely be available at any auto parts store?

I thought I read somewhere in the archives that Ford had a similar set up in some of their F-series trucks with dual pumps. Did they also use an accumulator?

 

[Mark]

In tank pump is the way to go.
I'm waiting for my dual pump setup to fail so I can switch to an in tank pump.
There is also a good thread here somewhere that attributes higher altitude cavitation and/or vapor lock occurring because of pumps external to the tank.

edit... found the thread... http://www.classicbroncos.com/forums/showthread.php?t=124079

 

[wpaeb]

I removed the stock sender used the pump and modified the bracket from a '93 mustang. I haven't worked out the sender yet. I have about 10 gallons usable fuel. This is on my trail rig.

 

[Nobody]

I prefer the external pumps. The OEM E2000 pump is a very good pump and widely available. I have mine mounted on the crossmember above the rear axle. I use all OEM factory fuel fittings. A second pump is not required.

I found that I need to add a small accumulator. That will also be one of the OEM's. I notice a little fuel starvation when I'm low on fuel, and heavy on the throttle around sharp corners. If the aftermarket tank had a baffle it would solve that issue. As is, it's really a non-issue. I'll fix it someday when I have nothing better to do.

The best part is, you can go to pull-a-part and load on on spare everything. Factory fuel system for cheap!

 

[lars]

I'll be the odd man out...

I have dual tanks (NWMP in back, stock plastic aux tank under driver) selected by a Pollak motorized 6 port valve, feeding a Carter low pressure pump, then a Bosch (Ford) high pressure pump, and finally a Ford high pressure filter. No accumulator.

I routinely fill, then empty both tanks before refilling, so the selector valve gets exercised regularly. It's worked flawlessly for 8 years and 40k miles. Summer and winter, sea level to 10,000+ feet, on road and way off camber. The engine has never hiccuped.

I can't claim that my system is better or worse than any other, but it's done the job for me. I've had to replace a few in-tank pumps on various cars and trucks I've owned over the years. I do not enjoy dropping fuel tanks for some reason. I loathe the idea of having to do it trailside, though as was pointed out above, you could cut an access hole above the tank to ease the pain. I do carry a spare high pressure pump, just in case.

 

[Dave]

I really like in tank pumps. To work correctly you need an in tank accumulator (or sump) like every vehicle with in tank pumps comes with from the factory. Here are some pictures of of my project using an Explorer in tank pump assembly and accumulator from the Explorer tank. Some of the GM pump assemblies include the sump as part of the drop in unit. If in tank pumps didn't offer some benefits vehicles would still have frame mounted pumps.


http://classicbroncos.com/forums/showpost.php?p=1336399&postcount=108

 

[zeeman1]

I have the external low-pressure to accumulator to High pressure pump, and would love it if I just had an EFI tank with the pump on the inside. I'd be a LOT less likely to damage the system at all, and it would get rid of the rats-nest of plumbing I have running around under there. Just seems safer and simpler to put it in the tank.

 

[Socal Tom]

I've burned up several LP pumps feeding accumulators. I also had a FORD RV with the dual pump system ( in tank LP pump feeding small accumulator). I've burned up several LP pumps. I suspect that the main issue is that LP pumps are not designed for continuous full speed use, and they eventually overheat and die. I'll admit I haven't used the carter pump, but I know others that have and also had a failure. I had the most success when I included a small valve on the outlet of the accumulator and kept about 3 psi on the accumulator.

Lars' system lacks an accumulator, so he avoids the "all out all the time" situation.

I'm currently running the BC 24 gallon tank with a single external HP pump. Its working fine. I haven't seen fuel stavation issues with this setup, but the BC fuel pickup is at the angled spot as the tank starts going up, so when you go uphill its in a good place. I also don't go on the trail with less than 1/4 tank ( 6 gallons). With a stock tank 1/4 tank is 3 gallons and since the bottom of the tank is shaped about the same, I think its safe to assume that my tank is 2 times as deep in as the stocker would be.

If you go with the dual pump setup, I would try it the Lars way first, using the Carter pump. If you decide you must have an accumulator add the restriction on the outlet of the accumulator so air can escape, but you maintain 3 or so PSI on the system.
Tom

 

[Bronco_69]

you can modify a mustang pump / sender to work in the bronco tank. i posted up some part numbers a few days back

all OEM use an intank pump for a reason

 

[trailpsycho]

I too am running a LP (carter 4070) to the E2000, both pumps are pretty widely available and can be swapped in minutes. I am not running an accumulator. The key is to make sure that the LP pump flows more capacity than the HP pump can flow. I have about 16K miles in the last 18 months and havent had any problems...other than some fuel filters clogging...from the tank sitting for a couple of years during the build.

As mentioned, the aftermarket tanks dont have the best baffling and you can get a small hesitation under heavy acceleration in combination with a left turn when there is less than 3 gallons in the tank...it doesnt stall, just hesitates a second till the fuel sloshes back over to the pick up. Unless you absolutely need a new tank (still running a stocker), I wouldnt spend the money on the in-tank pump-tank setup.

Another warning, I was originally using a compression fitting at the tank outlet, I found that the compression fitting was leaking/seaping, so I went back to standard fuel line clamps there. The compression fitting over time, aparrently, etched into the tube and allowed seapage under pressure (once the tank level is above the level of the outlet). So, I would stay away from the compression fittings.

Good luck.

 

[bronko69er]

Sticking with your 302?
Keep the mech pump as you feeder to the accum.
http://classicbroncos.com/forums/showthread.php?t=104144

 

[HoosierDaddy]

I have the dual pump/ accumulator set-up , if I were to do it over again , I'd use a single HP pump mounted right above the rear axle on the frame.
Others have done it that way and have no issues.
I don't see any problem with a dual pump NO accumulator set-up. That Carter 4070 is meant for a carb set up , which will mean the pump is dead heading against the carb inlet valves anyways.


EDIT ; If I had to do it over again using the same non-EFI tank , I'd just use one pump. If buying a new tank was an option , then that would be my first choice , in tank pump.