Gurgling From the Gas Tank

[70 FJ40]

This spring is the first time ive owned my 60 when its hot outside. The last few times ive driven it there is a definite gurgling sound coming from the gas tank and it is under quite a bit of pressure. I can remove the gas cap and relieve the pressure and the gurgling stops. Thre is also quite often a gas smell that fills the garage after getting home. The PO did quite a bit of work on the truck including a desmog. I'm pretty sure its not been done completely correct. I also had a new fuel tank put in at the dealer late last fall. Where do I check first to solve this issue and is it related to something missed on the desmog or something not hooked up correctly after a new fuel tank?

 

[Lead Head]

This spring is the first time ive owned my 60 when its hot outside. The last few times ive driven it there is a definite gurgling sound coming from the gas tank and it is under quite a bit of pressure. I can remove the gas cap and relieve the pressure and the gurgling stops. Thre is also quite often a gas smell that fills the garage after getting home. The PO did quite a bit of work on the truck including a desmog. I'm pretty sure its not been done completely correct. I also had a new fuel tank put in at the dealer late last fall. Where do I check first to solve this issue and is it related to something missed on the desmog or something not hooked up correctly after a new fuel tank?

There is a check valve inside the charcoal canister that likes to get stuck. I would first make sure the charcoal canister is hooked up.

 

[MWM1]

Charcoal canister full rebuild link below:

Thread 'Charcoal Canister Rebuild'

Sep 26, 2020

This post was a great guide that convinced me to try this rather than just replacing it with the ACDelco 215-153. I will follow up once I have more miles on it and can confirm that all is working.

A few weeks before doing the rebuild, I had used carb cleaner (B-12) to free up the check valves in the tank port. The check vales did free up and I could get some air to flow through that port but it was pretty minimal. It turned out to be not enough and I was still getting a 'whoooosh' when I pulled the gas cap after driving.

During the rebuild, I THINK I found what was restricting...

• coultl
• Replies: 23
• Forum: 60-Series Wagons

• 

 

[70 FJ40]

The charcoal canister is hooked up. Whether it's hooked up correctly, I don't know.

 

[70 FJ40]

How do I test the check valve? 

 

[70 FJ40]

Thanks for the thread @MWM1 I'll read up.

 

[70 FJ40]

There are 3 nipples/ports on the top of the canister. The front one hooks to a medal tube that runs to the back of the truck accrosst to the driver's side and back to the passenger side and goes to whatever that thing is called in the passenger cago side panel. Why does it run from one side just to turn and go back? The middle port is hooked to a tube that crosses to driver's side of the engine bay and is capped. The back one goes into a valve thingy? under the green electrical connection then over to the driver's side of the engine bay and is also capped. Does that sound like the way it should be done for a desmog?

 

[Lead Head]

There should be a tube on the bottom of the canister. As long as that bottom tube is open, I don't think the other two being capped should do anything. I suspect your check valve is stuck. See if you can blow into the "Tank" port on the canister.

 

[midknightc3]

Probably in the thread linked above would be the diagrams needed, but getting those capped lines hooked up would help your problem, though I agree that your check valve is probably stuck closed. Those two capped lines are supposed to vent the canister into the carb to be burned. On the bottom of the canister should be another line that vents into the frame rail, which if nothing is clogged would still prevent the bubbling. Also check that thingy in the rear passenger well and make sure it is hooked up correctly, if one of the lines is on the wrong thingy port it won't vent properly.