1997 4.0 SOHC P0455 GROSS leak detected

[allmyEXes]

For many months now I have been having a very strong fuel smell that I have been dealing with. There are not any raw fuel leaks visible and there is not a fuel mileage issue. I've read the PCM many times and clear it and the only code that will pop up is P0455, gross leak detected. And it is gross. When the engine is shut down you can smell it and it smells like it is in the front left fender area. I replaced the Vapor Canister Purge Valve / Solenoid with a Motorcraft one and no change. This is located above the left front inner apron.

Many say that you can access it under the battery. I preferred not to do it that way and risk breaking a 24 year old plastic line or connector. It didn't make any change in the condition. Instead of the expensive "parts swapping" method of diagnosing a problem I purchased a $150- smoke machine. I was finally able to get the vehicle up on our only lift at the Shop. 3 of us spent 30 minutes with the smoke machine hooked up to 2 different places and looking under the hood, front to back under it and looking at the top of the tank and the only place that a little wisp of smoke came from was the seam of the air filter box. That is not where the smell is coming from and a filter might help that isolated issue. When you use a smoke machine do so in a well vented area. Burning baby oil produces carbon monoxide.
We are all baffled and can't see any fuel injector seal leaks and even if there was a drip I don't think it would smell near as strong as it does. If the vehicle is occupied after the engine is turned off the smell will overwhelm the occupants.
I CAN'T FIND THE GROSS LEAK !

 

[donalds]

For many months now I have been having a very strong fuel smell that I have been dealing with. There are not any raw fuel leaks visible and there is not a fuel mileage issue. I've read the PCM many times and clear it and the only code that will pop up is P0455, gross leak detected. And it is gross. When the engine is shut down you can smell it and it smells like it is in the front left fender area. I replaced the Vapor Canister Purge Valve / Solenoid with a Motorcraft one and no change. This is located above the left front inner apron.
View attachment 423439
Many say that you can access it under the battery. I preferred not to do it that way and risk breaking a 24 year old plastic line or connector. It didn't make any change in the condition. Instead of the expensive "parts swapping" method of diagnosing a problem I purchased a $150- smoke machine. I was finally able to get the vehicle up on our only lift at the Shop. 3 of us spent 30 minutes with the smoke machine hooked up to 2 different places and looking under the hood, front to back under it and looking at the top of the tank and the only place that a little wisp of smoke came from was the seam of the air filter box. That is not where the smell is coming from and a filter might help that isolated issue. When you use a smoke machine do so in a well vented area. Burning baby oil produces carbon monoxide.
We are all baffled and can't see any fuel injector seal leaks and even if there was a drip I don't think it would smell near as strong as it does. If the vehicle is occupied after the engine is turned off the smell will overwhelm the occupants.
I CAN'T FIND THE GROSS LEAK !

You can get to it if you remove the wheel well liner But most likely cause damage to something or other
I recommend the battery tray method
I have removed my battery tray a few times 1nut and 3 bolts
Use as Wd40

 

[CDW6212R]

I don't know what else it would be, the smoke detector should be the trusted way to find all leaks. Are you doing the testing with the engine off?

I get a strong fuel smell from the rear of my trucks during hot weather, that I think is from the charcoal canisters being worn out. I bought two of those to install in my good project when I finish it. Those ran between $55 and $75 IIR, I got one and then realized later it had two.

Did you test all along the left side of the truck, the fuel vapor line goes from the front to the rear end area, it's all one AL line?

 

[donalds]

I flushed my canister with alcohol from the hardware store off the truck

Let it dry with a little help from a air gun
Been a expensive fix lmao

 

[allmyEXes]

@donalds I removed the well liner to get to the part.
@CDW6212R We looked at all of it several times. All 3 of us...

 

[CDW6212R]

Yeah, that's tough, many problems seem to be real gremlins that defy logic. Get pissed at it and drive the hell out of it for a short while, give it a wash and clean up, and try again to sort through the possibilities.

 

[donalds]

@donalds I removed the well liner to get to the part.
@CDW6212R We looked at all of it several times. All 3 of us...

Sometimes the battery acid leaks down and burning a little hole in that valve

 

[allmyEXes]

I have found the raw fuel smell. I removed the upper intake plenum on the chance that I might have a leaking fuel injector and I did. The far back injector on the drivers side was wet and when I took it apart the o-ring was damaged. I thought that I was being careful two years ago when I had it apart and reassembled it. Yesterday I really took my time fixing it. I installed 6 brand new o-rings and 2 new injector sleeves. Also new o-rings on the fuel supply line and the rear fuel rail jumper line. No leaks now and no smell. The leak was bad enough that after the engine was shut down the fumes would drive you out of the truck but it was not bad enough that it would run down the side of the engine and drip on the ground. My wife says now all that she smells is burnt baby oil from the "smoke machine". I thought about using coconut flavored tanning oil instead of baby oil. A spectator said "why not use hemp oil"?

 

[donalds]

Great to hear you found it
And remember

All the o rings are the same size on that fuel rail. Good info

"why not use hemp oil"? That would get expensive lmai

 

[allmyEXes]

I for sure won't forget about the o-rings now after fumbling around with the repair and picking your brain too. I'm glad that you were accessible. I'm currently reading my thread about how this whole thing on this white '97 started. It's amazing how much I can remember about it and how much that I have forgot.
Thanks again !