just woundering if anyone has chenged a intank fuel pump for in line mechanical fuel pump and what you did and how hard it was to do.
I want to do this to my 91 318
thanks dirty

 

All I have to say is good luck finding a mechanical fuel pump capable of pressurizing the fuel system high enough. Modern EFI systems require much higher fuel pressures than carbs did.

 

I think our pumps run up near 40-45psi

 

Early Ford EFIs used an external pump. The problem they run into is overheating or running dry - the submersed pump is cooled by the fuel it's surrounded by.

If you don't remove the intank pump you'll get too much of a restriction and it can cause your external one to burn up.

 

Ours do for the magnums. I assume the FI LA engines ran about the same.

But to me, a mechanical pump is not the same as an external pump. You can have an external pump that is electrical. Mechanical pumps are very old school and were designed for carbs that run under 12 psi.

 

I'd love to replace the in-tank pump with an external that would do the job just as well. The only reason I can figure for the Big 3 going to in-tank pumps is $$$$ for the service guys. They are pretty long lived, but when they start failing they are a PITA to deal with and most folks aren't going to drop the tank or pull the bed to do their own work. This is engineering for dollars at its best/worst.

 

Yes 95 318 is right guys. Mechanical pumps were designed with such low pressure and volume rate that it is insufficient for FI setups.

Think about it all the pump did was fill up the bowl in the carb and controlled by the float. The vacuum pulls the fuel from the bowl. Like said above carb pump is set for around 12psi. Stock FI is set for around 35psi. Now there also is the volume rate. Gallons per min. I'm not sure on what the rate is, but I'm sure it not no where close.

If you dead set on it, search for a EXTREAM HIGH Performance one. Read the specs and make sure it can handle your needed specs.

 

sorry about that - I'd missed the point with the mechanical unit. you'd have a hole in the bucket scenario with a mech - you need 40+ psi to run the injectors, the mech pump needs a running engine to produce the max psi/gph numbers needed to get the injectors firing. I don't believe it'd start - or you'd be cranking for quite a prolonged period before it'd start = your starter/battery would not like you anymore.