Fuel cap

[Peter60]

I took my Patrol for a bit of 4WDing yesterday. It poured with rain.

After some hours of driving, the engine lost power. However I kept going but then no power.

It felt like a fuel blockage but filter etc looked OK but there was a bit of air in the line. I decided to put some fuel in the tank. On opening the cap there was a noise of what I though was fuel vapor escaping. However a guy with me said it was the reverse - air rushing in.

I put the cap back on and the Patrol started and off we went. I stopped every so often to remove the cap to let air in!

Research today turned up vented and non-vented fuel caps.

Pre 85 cars need vented caps.

A tiny hole in the fuel cap makes all the difference!

[L60Boerne]

That is one of those great little tips! This is why I'm rushing to get my Patrols together and running.....because the generation of trained mechanics is fading fast. I've probably waisted 50% of my total expense due to either crooked or just bad mechanics.

I knew the bad mechanic problem in my area going in.

Patrolling past my problems,

L60Boerne

[RiverPatrol]

The Patrols actually don't use vented caps. There is a vent tube on the filler neck inside of the fender. If this gets plugged, like from mud while out 4 wheeling, it will cause the problem you describe. It will also make it difficult to fill the tank because the fill nozzle will keep clicking off - here in the states anyway because we have the evaporative recovery type at gas stations. Sometimes wasps like to build nests in the tube and it will cause the same problem. I've never actually experienced the lack of power situation but our Patrols have different carbs on them.

[Peter60]

Yes, thank you River Patrol you are correct. It is plugged. The rubber vent tube is missing altogether and a rubber plug is in its place!

I lost the previous fuel cap, which I assume was vented, and replaced it with what I now know is a non vented one. Hence my recent problem.

I don't seem to have a problem filling the tank, so I might just use a vented fuel cap from now on.

[L60Boerne]

Patrol Whisperers,

A picture of that sidestream vent tube would be educational.

I've seen both of my tanks removed and I didn't see any bent lines?

Thanks,
L60Boerne

[Esteban]

Patrol Whisperers,

A picture of that sidestream vent tube would be educational.

I've seen both of my tanks removed and I didn't see any bent lines?

Thanks,
L60Boerne

The following pictures shows the filler neck tube with its parts, and the other the fuel tank with the location of the vent (the pictures are not mine )

Fuel tank filler neck.JPG

[RiverPatrol]

In addition to the enormously helpful information Esteban just supplied, this is the top vent tube:

mystery_part_1.jpg

This attaches by a hose to the top tube of the filler neck (marked above 'open to air') and is secured high up in the wheel well to prevent submerging or taking in water.

[Peter60]

This is my breather (that I removed). It is just rubber.

Fuel Pipe Breather.JPG

[RiverPatrol]

Hehe, well, it looks close.