I have a 1997 F250 HD with two wheel drive, an automatic transmission, and a 5.8L that is fuel hydro-locking the number 8 cylinder when cranking to run. The fuel has been entering the block.
This is what I done so far:
Removed the oil pan, cleaned out the oil /sludge, (truck sat for a bit without oil it hardened in the pan.) replaced the oil, filter and oil pan gasket.
Replaced all of the fuel injectors with rebuilt units. Tried to start the truck, never started, then still the fuel is completely hydro locking the motor in the #8 cylinder.
Removed the spark plug, cranked the motor to drain the fuel.
With the spark plug removed, unplugged the injector, cranked the motor and fuel filled into the #8 cylinder. The coil wire was unplugged.
Removed all of the spark plugs, turned the motor by hand to drain the cylinders/check. Found fuel in the #8. The coil wire was unplugged
Replaced the #8 injector with an old unit. Installed all the plugs, plugged in the coil and cranked to start. Motor started, ran badly for less than 5 seconds then died. Cranked the motor sever more times, motor once again hydro locked. Removed the spark plug and fuel leaked out of #8 cylinder. Turned the motor by hand to drain the fuel.
My question is what is the problem and how do I fix it? Thank you I am lost…

 

Shot in the dark cause im not sure, but seeing as fuel is going in....something making the injector stay open?

 

Yea
I am going crazy with this one. I do not want to just start buying more parts. Oh wait I am crazy...

 

Bent or stuck open intake valve is my guess. With two different injectors and the fact you unplugged it and the cylinder still filled with fuel leads me to suspect an intake valve problem. Assuming your F250HD version is running a SD batch fire EEC-IV means that whenever any injector (or maybe just that side?) is told to fire all of them turn on for some period of time. So a lot more fuel could be dumping into #8. Compression check would confirm that theory.

 

Wow... I guess I could try that!!!
Thanks

 

I agree with Rla2005, do a compression test.

 

I will do that

 

No.. I don't see a valve causing this, I bet you're getting a ton of fuel into the intake via the FPR or charcoal canister. Pull the vacuum line off the FPR and switch the key on, if fuel shoots out it's toast. Also pull the vacuum line off the charcoal canister and let it hang low to see if any fuel comes out.. there should not be any just vapors. If there is fuel then you have a fuel transfer problem with your tanks.

 

Still seems odd only one cylinder appears to be getting all the extra fuel. I just threw that out there as a "possible maybe". A quick check with a compression gauge will prove me wrong or right. Conanski has another great suggestion of a possible cause. This should get really interesting.

 

If a valve was stuck open, it would not hyrdolock, just push the fuel back into the intake or exhaust depending on which valve was stuck open. It is strange that only one cylinder is flooding since if the injector was shorted to ground, all four in that batch should also be flooding. Unless, of course, it's a California truck with mass air and sequential EFI...

 

Good point, but then this is also happening pretty quik, the piston is not going to beable to move or compress a fluid as quik as air, so when the pressure is building, it may not beable to push fluid through and open valve fast enough.

 

We Also know that the oil sludged up in the engine, and that could cause a valve to stick open.
And remember, the engine is not going to sit level. when changing the injectors on a diesel, you take out the rear most injector first because the fluids drain to that side.

 

I wanted to thank everyone that has contributed their expertise on resolving my problem.
THANK YOU!!! THANK YOU!!! THANK YOU!!!
I have solved this problem and discovered a new problem.
The old problem was the Fuel Pressure Regulator, the diaphragm must have been ripped, and fuel was entering the vacuum line and feeding back into the intake and then running into the #8 cylinder.
My new problem must have been created by the fuel hydro locking the motor. Upon starting the motor I soon realized large amounts of white smoke coming from the tail pipes. Yep, antifreeze/water in the exhaust, so it seems to me, I now have a blown head gasket. Once again, THANKS EVERONE for the help, I now know what I will be doing for Thanksgiving.

 

Good call Conanski. Sometimes it takes several viewpoints to work out the theories. The intake valve was a long shot, glad it turned out to be something relatively simple. The problem is now you know the engine has been washing down with excess fuel for some period of time. Good luck with your new ride.

 

Why were my replies removed from this post? Is that what happens when there is a difference of opinions on this site?