1994 F-250
7.5 ltr Gasoline
184,000 miles

Youtube link: I recorded a quick shot of the leak.
https://youtu.be/oz8PWB-E3s4

Hello, I am looking for input to brainstorm how this is even possible.

First, yes this is the EGR, not the Fuel pressure regulator.
It's about baseball size, with a vacuum line and a 2 wire connector plug, a line that runs into the exhaust l, and is mounted to the driver side of the intake manifold post throttle body.

The context:
The truck has ran great for years. Recently it began hesitation at freeway speed and would stall at low speed such as trying to maneuver parking. After changing fuel filter everything was great for about 60 miles, then the problem persists.
After running Seafoam and Injector cleaner through a whole tank, the issue went away for about 80 miles. Now it won't even idle under its own power.
The truck will start immediately if it has been sitting for a few hours, it will sometimes idle ok for about 5-10 seconds, then will begin to stutter, choke, and stall. Even under constant steady throttle, the RPM will fluctuate 1,000 RPM on its own and then stall. It will backfire a lot too but the Cat was deleted and the airpump still feeds into the exhaust si thats expected until I delete the pump.
I noticed a heavy presence of fuel smell each time it stalls. I checked the pres regulator vacuum line, no fuel. Blew into the regulator with a hose and it has no leak so the diafram is OK.

I checked for vacuum leaks with carb cleaner to no avail.
I replaced the MAP and found no difference.
TPS look ok but havent tried replacing.

The discovery:
To double check for vacuum leaks the redneck way,, i fogged the **** out of the engine bay with carb cleaner (extinguisher handy), to no avail. When the truck inevitably died 10 seconds later i got a phone call so I'd left the Key in the "running" position not thinking about it. During the call the gas smell got really strong and I kept hearing a sound like pressure flowing. After about 4 minutes I looked at the EGR and saw gasoline dripping from the backside of the flange at an alarming rate.

I am aware of the plethora of issues I could be dealing with in tandem, such as just about every sensor in the engine bay, I've even considered timing or timing chain tension, the distributor shaft or pin, the Computer itself being bad, injectors, IAC (seems unlikely), or of course the EGR. However I don't really think the EGR is the cause here, I'm thinking this is a symptom.

The question:
If you were curious enough to read this far, Thank you!
In your opinion, how in Sam Hell is raw fuel making it into my EGR, and leaking out? I have replicated the leaking once, but haven't had the chance to really see where its leaking from the EGR because i'd have to start it and I don't want to hydraulic the cylinders with all that fuel, haven't had time to pull the plugs yet.

My only theory thus far:
Injector stuck open, dumping fuel when the key is in the running position even after stall, cylnder fills entirely after a few minutes, leaks through the exhaust valve, fills the EGR with raw fuel.

If this is the case, why is the fuel leaking out of the EGR instead of running down into the headers?
Its safe to assume i have a leak at my EGR, so would this cause any of my above symptoms in your opinion?

Quite the mystery to me thus far. Any input is greatly appreciated, and I thank ya for your time.

 

We need to start somewhere and I believe a good place to start is checking the fuel pressure in the system. The system when shutdown will hold fuel pressure for quite a while. If the pressure is too high , that would point to the pressure regulator, which could be the problem until the pressure check proves otherwise.
Pressure specs for a 7.5L engine are,
engine running, 30-45 PSI
Key on engine off 35-45 PSI We don't know at this time if the regulator is faulty or if the return line is restricted until we see the readings.

With the gauge connected to the pressure check fitting , watch the pressure after the engine is shut down.
You will probably see the pressure drop . Are we sure the fuel is not coming from an injector connected to the injector feed line , but close to the EGR valve.
Not too sure of the engine always stopping at the same cam position where the exhaust valve is open enough to allow fuel to come through there.
There is something that causes some questions and that is , it seems to run fine each time you replace the fuel filter , and always starts right up which would kinda steer me away from a leaking injector internally into the engine. From what you describe ,you can hear something like fuel squishing out . That would to me be an external leak.that could be spraying on to the EGR valve. What if you used a mirror and flashlight to observe that area after you shut down the engine?

 

First, thank you for your input!

I don't have any pressure test tools, I will rent one if I need to, and thank you for the specs so I can reference them. I did however order a fuel pressure regulator because after the MAP that was my original 2nd suspect before finding the leak. I will try installing the regulator after removing plugs to drain any fuel still in cylinders and will note my findings.
I am not exactly sure how the EGR itself would leak, but it really looked like the EGR had fuel spilling out of it. I will investigate that further and will update what I can find.

Another note, CEL is not on. I did have a code at first, but I was sorely disappointed when it flashed 5,3,9 and I realised it was just telling me my AC was switched on. After turning it off it was 111 system ok.

As a truck driver I don't have a lot of free time during the week so if the weather is good I do most of my work on the weekends. Thanks again for the thoughts.

 

There are a lot of knowledgeable folks here, and It is a good place to get some help.

 

I’d be leaning to injector/s hung open, more so if your hear fuel being dropped with no Tach/RPM, KOEO and no visible leak. Fuel pump run is PCM timed for the start/no start, so if it runs continuous (?) KOEO, there’s an issue. It’s not uncommon to hear pressurized fuel being circulated through the rail KOEO for a short time when the key is cycled.. But without an injector ground being supplied, fuel would just rail circulate..
As you noted, unmetered fuel would be exhaled and possible into the EGR passage. That said, you’d likely see rich fuel deposits or even droplets exiting the pipe, or evidence on the paint etc if severe enough. Quite often with injectors stuck as you mentioned, the offended cylinder will hydro lock on a cranking attempt, but not always and would depend on puddled fuel volumes.. Also if an intermittent fail, meaning static, or run time induced..
Another thing, may be to check for injector/s being ground activated, uncontrolled. Using a analog meter or noid light, meter pegs, or an illuminated noid within a no run event, may indicate control shorting /grounding..

The stalling, flooding, rough idle, inconsistent performance/steep RPM variations, heavy fuel smell and visible depositing would need a ‘decent’ source. Fuel reg can make for some of the conditions, certainly checked, but most often if the diaphragm is blown, fuel will spill out either manually removing the hose and checking it, or under engine run times with a consistent leak from the reg hose fitting ...

TPS, MAP, global enrichment possible, but generally the TPS will suffer or have drop outs, most often with a CEL, possibly intermittent.. If the TPS registered WOT it could make for off spec enrichment, would be a global affect though, not just a cylinder or two, and you could disconnect the connector to see if any over fueling corrects for idle..

If an injector/s seem likely, warming the engine, cold, hot soak etc to duplicate the event conditions and removing the spark plugs and short crank to verify any unmetered fuel expelled would prove out Y/N for cause.