Fuel leak at the IP on my 91.

[BigRigTech]

I've been smelling fuel for about a week, today I noticed the valley pan was kinda wet with fuel. I washed it off with brake cleaner at work today and checked it when I got home - wet again...It appears to be coming from the bottom of the IP. Any common area's for it to leak? The truck still starts and runs great, no issue's that way. Might be time to hit ebay for a pump eh? I'm not sure what the local IH or Ford dealer will want for one.

 

[Mr_Roboto]

Make sure it isn't coming from the lines. The input (center) line has a rubber "olive" that seals it, and the high pressure lines can develop cracks right next to the nut.

 

[BigRigTech]

I think it might be the center line, it was wet when I washed it off earlier today. Can I buy the "olive" seal at Ford or IH???

 

[argve]

yep sure can. There is also an oring that seals between the nose cone and adapter fitting on the very end - this is also a source of leaks

 

[rjnerd]

I've been smelling fuel for about a week, today I noticed the valley pan was kinda wet with fuel. I washed it off with brake cleaner at work today and checked it when I got home - wet again...It appears to be coming from the bottom of the IP. Any common area's for it to leak? The truck still starts and runs great, no issue's that way. Might be time to hit ebay for a pump eh? I'm not sure what the local IH or Ford dealer will want for one.

One that I saw on a F450 - the line to one bank has a metal clamp on it halfway. In our fine salt atmosphere, moisture collected under it, and the line wound up with a pinhole under the clamp. Took out the line, and had a brake joint fab up a replacement.

 

[BigRigTech]

I'll take a look tommorow and report what I find.

 

[Mr_Roboto]

One that I saw on a F450 - the line to one bank has a metal clamp on it halfway. In our fine salt atmosphere, moisture collected under it, and the line wound up with a pinhole under the clamp. Took out the line, and had a brake joint fab up a replacement.

Ouch. The injector lines are very special. They are 1/4" OD and the passageway inside is tiny, maybe 1/16".(Edit passageway is between 1/16" and 5/64", making for a wall thickness of @ 3/32") This makes a VERY thick wall. There is NOTHING in a brake system with that kind of wall or to handle that kind of pressure. Not only must the lines handle the pressure, but they must resist expansion with the injection pulses.

The input line can be replaced with anything - even rubber hose because it is low pressure. But it sounds like you are talking about one of the high pressure lines.

 

[BigRigTech]

I'm with you Mr, I was thinking the same thing.....

 

[Diesel JD]

The hard line from the filter to the pump is not special as it is low pressure. The fuel injection lines going from the back of the pump to the injectors are. There are several areas you could have a leak at the back of the pump.
1) The nut is loose 2) The rubber washer is degraded and leaking. 3) The injector lines are loose or broken 4) The pump has a shaft seal leak and is leaking out the weep hole(added on later 6.9 and all 7.3 pumps so the crankcase doesn't get filled with leaked diesel)

 

[BigRigTech]

Good info, I'll check all that stuff in the morning.

 

[rjnerd]

Ouch. The injector lines are very special. They are 1/4" OD and the passageway inside is tiny, maybe 1/16".(Edit passageway is between 1/16" and 5/64", making for a wall thickness of @ 3/32") This makes a VERY thick wall. There is NOTHING in a brake system with that kind of wall or to handle that kind of pressure. Not only must the lines handle the pressure, but they must resist expansion with the injection pulses.

The input line can be replaced with anything - even rubber hose because it is low pressure. But it sounds like you are talking about one of the high pressure lines.

This was a common rail system, with one line to each bank. The tube was fairly large in ID, and sure looked just like brake line. I have seen conventional injector line, and this stuff was not like it.

 

[BigRigTech]

I had a look at my IP this morning, I'm pretty sure I found the leak. The nut on the fuel supply line to the IP was loose at the IP. I snugged it up a little and took it for a run - dry as a popcorn fart......I put a white cloth serviette under the IP and so I can check for any signs of a leak for the next week or so....My kinda repair - free......This might explain the "hiccuping and kicking" cold starts for the last 2-3 weeks in the mornings, it might have been loosing a little bit of it's prime over night with the fuel all leaking out on the valley pan.

 

[Mr_Roboto]

This was a common rail system, with one line to each bank. The tube was fairly large in ID, and sure looked just like brake line. I have seen conventional injector line, and this stuff was not like it.

I assumed you were talking about an IDI, people have a tendancy to call F-Superduty's "F-450's" since they are similar.

 

[MIDNIGHT RIDER]

I assumed you were talking about an IDI, people have a tendancy to call F-Superduty's "F-450's" since they are similar.

In the IDI years, a Superduty and an F-450 were one and the same, with ten-hole wheels, straight front axle, and front leaf springs.

Later on, Ford used the SuperDuty name on their new body-style of trucks, regardless of weight capacity.

 

[BigRigTech]

I would say my leak is fixed, I just had to go in to work for a service call (broken fan drive belt on a CAT C15) and when I got home I checked the valley pan - dry as a fart...