Fuel Leak under Intake Manifold (?)

[Ninerslr]

searching for a solution was un-successful, so here goes:

We have a 1991 3.0l 6cyl 4wd 4-Runner with 246,000 that began emitting a strong smell of gas about 100 miles ago.

After stopping yesterday morning, we began hearing a dripping of fluid onto a hot surface and an even stronger smell of gas.

After climbing all over the engine, we traced the possible leak to a spot that we could not see; beneath the intake manifold, right next to the firewall.

In researching these forums, we found the attached diagram and believe it is the #2 fuel pipe that is leaking, but are completely unsure.

Questions:

1. If we are correct that it is the #2 fuel line pipe, has anyone replaced this line before and what caused the break?
2. Are we completely looking in the wrong direction and is there another, more obvious cause that we are missing?


Sorry, this is my first post to this forum and I appreciate the patience and advise.

 

[Bad_Vision]

age, things get old and break might be the copper crush washer that failed.
You have to remeber that the engine is always vibrating this can cause all sorts of things, i had a zip tie vibrate a hole in a vacume line once!
It is not uncommon for things to just happen from years of use.

 

[Ninerslr]

Thanks, BV; will keep looking at all the joints/connections.

Doing more research it appears we will have to remove the intake manifold to get a better look... all it takes is time and money, right?

 

[77'911]

You might need and consider pulling the intake and resealing the fuel system with new copper o-rings and upper/lower injector o-ring seals. I found ours was a injector o-ring. You'll be pleasantly surprised how much better the truck runs and starts afterwards. I doubt the feeder lines themselves are leaking as they are fair robust in construction. Hope this helps.
regards

 

[Bad_Vision]

77'911 is right when you pull it all apart just replace all the seals and orings they are really cheap and the hole proscess should only take a hour or two.

 

[77'911]

Nineslr, you might also consider replacing the pcv on the passenger side valve cover. It is much easier to R&R, while the intake is pulled. That $5 part can be the cause of a lot of head ache if let go.
regards

 

[Ninerslr]

BV & 77911; thank you both for the ideas. I've got some work to do and much appreciate the direction. Will post the outcome at a later date!

 

[Ninerslr]

Final Report:

Leak was found and fixed.

In 77'911's picture, the right fuel injector rail (left side of picture, right side of engine) has a pressure "dampener" at the far end of the rail. You can sort of see it behind the paper towel in the picture. (Round bell looking device)

The dampener had opened up on top of the end cap and looked to have released pressure through the actual end cap. The dampener was hidden under the intake manifold, so we couldn't see the leak while the system was pressurized.

This project was the first real engine work I have done. Now I'm hooked!

Reading Chilton's book, the injector job was about 15 instructions long.

The first line was a short 4 words long: "Remove air intake manifold". That only took me 4 hours...

Thanks again for all the help. The Green Machine rolls on! (246,000 miles and counting!)

S