Mechanical/electric fuel pump combo?

[dodgerammit]

About to get ready to install a low pressure (4-6psi) in tank pump on the Waggy to combat vapor locking issues I am having.

Is there any real reason NOT to leave the mechanical in place as well given both are flowing the same rate and pressure?

Basically, each would be a supplement to the other.

Thanks.

[Cheapthrills]

I would cap off mechanical becuaseif mechanical fails you will dump fuel into crank case..

I left mine installed and capped in/out ports because I'm too lazy to take it out and instal plate

Sent from my SM-N920V using Tapatalk

[68glad]

When the diaphram goes bad in the mechanical pump the electric will fill the crankcase with gas.

[dodgerammit]

Mechanical is new, just not sure how long I should expect a parts store pump diaphram to last.

Next question: Where can I find a block off plate?

*Edit
Nevermind... http://www.bjsoffroad.com/Fuel-Pump-Blo ... p_555.html

[4bz]

I run a mechanical and an electric simultaneously in two of my rigs (77 cherokee and 62 willys wagon). I also have a dash mounted fuel pressure gauge in each. If you run the mechanical pump as primary, you will know right away if it fails; it does not hurt the electric to be connected in-line and not running while the mechanical is doing the primary duty. A switch on the dash can be used to control the electric pump. If the mechanical pump stops working, a piece of rubber fuel hose can be used to bypass the pump, and the electric unit will get you out of the woods or back home again. Other than simply being a backup to the mechanical pump, the electric gets used to prime the carburetor if the vehicle has not been driven for more than one week, or when I have done engine work and drained the fuel out of the carburetor.

[Tatsadasayago]

4bz, that's how I've been running my vehicles for two decades. The electrical pump simply free-wheels when not in use and presents very little resistance to fuel flow, but is there when you need it. A mechanical pump diaphragm less than a few years old is not likely to fail under normal circumstances so filling the crankcase with fuel isn't a big concern.

[jsinajeep]

I run both on mine also, and use the electric as a back up for when it vapor locks. Just hit the switch
and let it run for a bit.

[dodgerammit]

Hmmm, interesting replies guys. Thanks. I'll run both for a bit and see if the issue is resolved before I commit to doing the block off. If the issue is resolved, I'll probably consider the next level (EFI) in the future.

[will e]

The suggestion to put a fuel gauge in the cabin is a good one. What carb are you running?

[dodgerammit]

2150. What fuel gauges does everyone run? Where do you have yours mounted?

[tgreese]

Heck, people object to running a mechanical oil pressure gauge into the cabin. No way would I run a mechanical fuel pressure gauge into the cabin. I thought these gauges were meant for use under the hood, not in the cabin. There are electric fuel pressure gauges, which IMO would be the right choice if you want to put the readout in the cabin. Usually the mechanical gauges are meant as test instruments, or are mounted under the hood as a help for tuning.

The Summit mechanical FP gauges are about $20 each, and the Summit electric FP gauge is about $60, but it gets poor reviews. The name-brand electric FP gauges are over $200.

[dodgerammit]

Looking at speed hut gauges since they are the most reasonable with what appears to be decent quality.

http://www.speedhut.com/gauges/Pressure ... 7&i=18&p=1

What pressure does most tbi systems run around? Primarily the GM based systems.

I'd like to get a gauge that can be used with the carb now AND with tbi in the future if possible.

Thanks.

[dodgerammit]

Heck, people object to running a mechanical oil pressure gauge into the cabin. No way would I run a mechanical fuel pressure gauge into the cabin. I thought these gauges were meant for use under the hood, not in the cabin. There are electric fuel pressure gauges, which IMO would be the right choice if you want to put the readout in the cabin. Usually the mechanical gauges are meant as test instruments, or are mounted under the hood as a help for tuning.

The Summit mechanical FP gauges are about $20 each, and the Summit electric FP gauge is about $60, but it gets poor reviews. The name-brand electric FP gauges are over $200.

Nobody ever stated mechanical gauges. Just recommended a gauge to monitor with.

I'm not a fan of any pressure lines running into the cabin either.

Any gauge I run will be electric.

[Curly]

Looking at speed hut gauges since they are the most reasonable with what appears to be decent quality.

http://www.speedhut.com/gauges/Pressure ... 7&i=18&p=1

What pressure does most tbi systems run around? Primarily the GM based systems.

I'd like to get a gauge that can be used with the carb now AND with tbi in the future if possible.

Thanks.

GM TBI systems typically run 11-13 psi.

[dodgerammit]

Cool, so a 15 psi or even a 30 psi model would be sufficient.

[j10jim]

Speedhut gauges are the bomb!!

[az chip]

I use mini Isspro ev2 series gauges for fuel pressure and other items. You can find them for around $100.


Sent from my iPhone using Tapatalk

[dodgerammit]

I use mini Isspro ev2 series gauges for fuel pressure and other items. You can find them for around $100.


Sent from my iPhone using Tapatalk

Where did you find them for $100? All of the ones I've found are $180ish and you still have to buy the sender separately.

[az chip]

I buy them at Geno's Garage or Xtreme Diesel.com I see they have gone up. Last I bought one was 2014.

https://www.genosgarage.com/product/iss ... -ev2-black

[Tatsadasayago]

FWIW: An electrical oil pressure gauge will do the same job for cheap. Just label it
Fuel Pressure and yer done.
I mention this because I use Autometer temp and pressure gauges for engine, trans, fuel and diffs for very little expense.