Question for Innovative

[2008powerstrokef350]

Originally Posted by 07stroker

Can those injectors push enough fuel to actually hydro-lock a cylinder....if they can thats impressive. I mean wasn't the flame thrower in the early 6.4's caused by a leaking injector or stuck open injector or something like that??

yes they can i have a job 1 08 f350 and with 9000 milles on and i have had #6 cyl, piston and rod replaced. stock truck no chips no exhaust no nothing!

[RedMule]

Originally Posted by 2008powerstrokef350

yes they can i have a job 1 08 f350 and with 9000 milles on and i have had #6 cyl, piston and rod replaced. stock truck no chips no exhaust no nothing!

Now that is interesting. Glad it was under warranty.

[fordfish]

^so a tuner doesnt cause or lead to this issue. It should be warranty tuned or not

[DavidPhillips]

It takes very little fuel in a closed cylinder to hydrolock it.

What made the pump fail is the question that will be discussed and the warranty coverage will depend on that decision.

What is troubling is the fact that a failed pump means damaged engine. Why is there not a screen or something to prevent catastrophic failure?

[redracer62]

ive seen a 6.4 pulled out of the truck with a bent rod sitting on top of the motor all crated up ready to ship back to ford

[737tdi]

I have the 6.4 bible downloaded on my computer but it is also available here.
The Powerstroke 6.4L Bible!
The reason I am adding this is because if you open the fuel system file there is a very good simplified schematic and good explanation of the system. This guy is right about the 3 +/- .5 psi., but as far as a tune causing a problem with this I just don't believe. The pressure is regulated by a mechanical poppet relief valve in the filter housing routing fuel back to the HFCM, has no communication with the computer. Also if you read on down is says the cracking pressure is 2psi. and actual pressures may be lower or higher.

I guess to get to the point, I just don't believe it is as critical as it is being portrayed and having a tune or any other mod. is going to have 0 effect on the operation of this portion of the fuel system. I'm not saying it "can't" fail but if it does it has nothing to do with a mod. J.M.O.

737tdi

[George C]

I guess to get to the point, I just don't believe it is as critical as it is being portrayed and having a tune or any other mod. is going to have 0 effect on the operation of this portion of the fuel system. I'm not saying it "can't" fail but if it does it has nothing to do with a mod. J.M.O.

If it is strictly a mechanical feed and monitored by a mechanical valve, then I agree. There can be no way a tuner could alter the pressure of the fuel supply. If all is true, I wonder how Ford can attempt to pin the fuel supply pressure directly to a tuner.
Is there anything else directly or indirectly changing fuel pressures anywhere else in the supply system that could be somehow altered by a tuner's affect?

[DavidPhillips]

Unless..

the fuel used is more than can be supplied from the tank and it starves the pump. This is highly unlikely on this truck in my opinion. After modifying my old Chevy truck however the fuel pressure would go to 0 psi at the injection pump when it was run hard and a better or second lift pump is needed to maintain the required pressure to prevent pump damage.

The problem can't be ruled out by assumption. Somebody needs to install a gauge and test it.

[George C]

Originally Posted by DavidPhillips

Unless..

the fuel used is more than can be supplied from the tank and it starves the pump. This is highly unlikely on this truck in my opinion. After modifying my old Chevy truck however the fuel pressure would go to 0 psi at the injection pump when it was run hard and a better or second lift pump is needed to maintain the required pressure to prevent pump damage.

The problem can't be ruled out by assumption. Somebody needs to install a gauge and test it.

Considering the instant fuel draw when an agressive 200-250 hp tuner starts drawing fuel when the driver floors it..

This is very possible.

[737tdi]

This info. is straight out of the Ford Powertrain Control/Emissions Diagnosis Manual for our trucks. The HFCM supplies 5 to 10 p.s.i. to the secondary fuel filter at idle, as said earlier the pressure relief/return valve inside this filter housing is set to relieve at 3 p.s.i.. So this indicates positive pressure to the filter thus to the High pressure pump. Also if you look at the HFCM it relieves pressure at 24 p.s.i. indicating it has alot more pressure capability.

"After the low pressure fuel is filtered by the secondary fuel filter, it enters the high pressure fuel injection pump. When the fuel reaches the high pressure pump, it's pressure is stepped up by the transfer pump. The transfer pump is internal to the high pressure fuel injection pump and is driven by the high pressure fuel injection pump main shaft. A portion of the fuel leaving the transfer pump flows to the lubrication valve which allows the fuel to lubricate the mechanical components of the high pressure injection fuel pump. Fuel that is not used for pump lubrication is directed to the fuel volume control valve."

My reason for adding all of that is the last sentence, this is all happening prior to any control by the pcm, and is also before any fuel reaches the high pressure portion of the pump/fuel volume control valve which of course is where the fuel pressure is then increased up to 24,650 p.s.i..

As I see it the last thing to be starved of fuel would be the lubrication portion of the high pressure pump, if there is a fuel starvation event I believe the pump would simply not be able to supply the high pressure/volume to the fuel rails/injectors.

I'd like to see some more input by maybe some actual diesel engineers. I am merely a aircraft mechanic with a working knowledge of turbine fuel systems/main engine controls and a shade tree mech..

737tdi