3fe external fuel pump

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Question, why did mmw's 60 need so much more fuel compared to a stock 3FE?

Or was it as simple as the pump or the bypass going bad?
 
I think it was a bad pump problem but in the process of upgrading all the intake/exhaust stuff in it I kinda got carried away with the whole thing. I am am sure I could have just run the MSD in line and it would have been fine but I was looking at what would make it easier and cheaper if he had to replace parts or trouble shoot the fuel system. on his 40. So far he has had great success with the combination.
 
So very likely, the stock bypass and the MSD pump will be just fine right?
 
The fuel pump I have is running it fine at idle. I haven't driven it on the road yet. I'm waiting on a EFI Main Relay, should be in tomorrow. The part they overnighted for this AM was the Cirquit opening relay.

Everything in the efi/fuel system tests good except for the EFI Main Relay, which fails one of the tests. No power to the fuel pump.

I ran a hot wire to the pump to crank the truck, so that's how I know it idles.

I'm hopeing that the EFI Main Relay fixes the problems, especially since I'm supposed to be done setting up my tent at Katemcy exactly 7 days from right now!
 
Moby said:
Yeah, I've heard of converting new style "deadhead" EFI fuel systems to a return line but never the other way around. I'm not sure why OEMs have gone to the deadhead style in recent years. I'd be very interested in hearing more if anyone has insight into the pros/cons of deadhead vs. return line designs for EFI fuel systems.
Click to expand...
Newer EFI systems use a Pulse Width Modification (PWM) method of controlling the fuel pressure. Some have a constant bleed in the system somewhere, others do not.
For those unfamiliar, PWM is simply turning the pump on and off at, say, 30 times per second. How long it is on vs. how long it is off is "Duty Cycle". More Duty Cycle, more fuel pressure.
With this method you can run the system deadheaded and don't need an FPR, but you do need a computer monitoring the pressure and adjusting the PWM on the fly.

The only advantage to deadheaded that I can see is less pressure pulsation in the fuel rails, so each injection should be more consistent.

Personally, I would use the Bosch or the Walbro 255 liter per hour pump over the MSD pump. Those pumps are designed with a high MTBF rating like an OE pump. I don't know that the MSD units are.
 
Cool , so it is more of a constant pressure vs constant volume adaptation.. Interesting.


ntsqd said:
Newer EFI systems use a Pulse Width Modification (PWM) method of controlling the fuel pressure. Some have a constant bleed in the system somewhere, others do not.
For those unfamiliar, PWM is simply turning the pump on and off at, say, 30 times per second. How long it is on vs. how long it is off is "Duty Cycle". More Duty Cycle, more fuel pressure.
With this method you can run the system deadheaded and don't need an FPR, but you do need a computer monitoring the pressure and adjusting the PWM on the fly.

The only advantage to deadheaded that I can see is less pressure pulsation in the fuel rails, so each injection should be more consistent.

Personally, I would use the Bosch or the Walbro 255 liter per hour pump over the MSD pump. Those pumps are designed with a high MTBF rating like an OE pump. I don't know that the MSD units are.
Click to expand...
 
Mace said:
Cool , so it is more of a constant pressure vs constant volume adaptation.. Interesting.
Click to expand...

So I thought about this comment some more - wouldn't the constant volume pump combined with Fuel Pressure Regulator, fuel pulsation damper and return line basically equal constant pressure?
 
PabloCruise said:
So I thought about this comment some more - wouldn't the constant volume pump combined with Fuel Pressure Regulator, fuel pulsation damper and return line basically equal constant pressure?
Click to expand...

Vs a pump with essentially constant pressure.. less stuff to go bad and less stuff to troubleshoot..

Not saying I agree with it, just that it is interesting :)


AWESOME!!!!
 
Installed on the PS frame of myh 62 with brown davis tank
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