Hi
I've been smelling diesel for a few months whenever I drive. If the truck sits a few days, the smell goes away, but comes right back when driven. When checking underneath, there is minor fuel residue (a few droplets hanging) and most of it is forward of the tank. Had the VP replaced recently, so took it back and they made sure all was tight. I did find a slow seapage coming from my RAPTOR 150, so I replace that.
After degreasing underneath today, I took it for a short 3mile drive and back. When looking underneath, it appears there is some leakage coming from (see photo) this "plate" on the lower portion of the engine...took a photo because I'm not too savvy with mechanics. What does this plate cover (3 bolts; size 5/16)?? I did put a wrench on each bolt and was able to snug each one a small amount; each was slightly loose, but not excessive. Will try to include PHOTO (see blue tape on the plate in question). Note: I THINK it is diesel fuel, but not 100%. It is mostly clear and doesn't feel like oil (certainly not dark).

 

Usally that will be oil from rear main or atf from front seal of trans. If it is fuel make sure the inj tubes are not leaking at the head.

 

Thanks. So, that plate covers the compartment that contains ATF?
Question: Ref the injector tubes, that would be ON TOP of the engine--right? where the fuel lines from the VP go into the TOP of the engine--right?(again, sorry, not as mechanical smart as I'd like to be)

 

you might want to check the #6 injector line..or the return line at the rear of the head..

the plate you're talking about is part of the tranny not the engine.

-dkenny

 

Not exactly. That is the bell housing and if you pull the cover all you do is see the torque convertor. You might be able to tell if the tranny has a leak there though.

 

Look to see what is dripping out if its black I would say its motor oil from rear main seal if it has a red tint to the oil I would say the trans front seal has a leak. You can catch the drip on your finger and smell it if it smells like diesel then it would be working its was domn from the top of the motor.

 

Yeah, this is shaping up to be not good...might be an easy fix for a mech., but I'm not sure I know how myself...
So, today I went out and cleaned underneath real good (degreaser, then sprayed off). Then a short 15 mile run to town and back. Here's what I noticed:
--Fuel mileage has dropped by almost half. Normally I average about 19mpg; computer is reading 12.5MPG !!
--My boost is almost zero (as measured by the Quazilla Commander); normally fluctuates around 11-18-ish.
--When coasting, my "instant" MPG drops to 5-8mpg...normally while coasting or downhill it's 35-45+ (just for short periods)
--My "instant" MPG seems to increase whenever I accellarate...that's real odd as it should drop.
--My fuel pressure is around 10psi (the RAPTOR 150 is adjustable, but 10psi is sufficient I think)
--Here's the real telling part: There is fuel all around the lower half (where the photos shown earlier are at).
MY SUSPICION: I think I have fuel leak from the fuel lines up on top of the engine. There IS some leakage around a couple of the inlets (I can probably tighten those up, but reaching back to #6 is going to be tough.
Also, since I replaced the previous RAPTOR PUMP, maybe I need to bleed some air out (that's what worries me because I'm not sure exactly how to do that CORRECTLY).

The engine runs fine and is not missing or acting up, but the MPG drop and fuel obviously coming from SOMEWHERE gives me the *******...

 

My 2000 did almost exactly as you describe. Mine was the return line at the back of the head. Took a bit to get it to stop.....

 

Their is no doubt you have a fuel leak park it, find it and fix it before you have a fire.

As others have said check the lines at the back of the head.

 

Thanks, I have a feeling that is what it is...dropped it at the shop today...if they call and tell me they can't find it, I'll ask 'em about the return line.....thanks!

REF post about "stop before catches fire" that's what I was thinking too...glad the weather in S.Texas is curently cool...no doubt summer road heat would be dangerous!

 

when my 53 block was cracked the wind and fan blew the coolant back and it dripped off at the exact same stop and through me off track.

coolant would run straight down to the ledge of the oil pan, run to the rear, then down the rear bell housing and off the inspection cover.

straight up is the fuel return, it has a tee with rubber sleeves in the connections, rear of block left side. at the rear of the head is a banjo bolt with sealing washers.

that is where i would take a real close look.

fuel is not considered flammable, it is combustible.