Gas tank venting?

[60Man]

So I have a question about the vapor separator on my ’87 fj60. This has had the recall preformed back in ‘97. I think I am experiencing some problems with the venting of the gas tank, or vapor locking. The truck has 125k and it is all OEM. I just started to experience some vapor locking symptoms. Some bucking at low RPM with a fuel tank of less than half full, and some difficulty starting after the engine is hot. I am not convinced that it is vapor locking because it has been starting with less than 5 miles into the drive and it just started in the cooler weather of late September in Buffalo NY. Today I drove the truck twice for about 6 miles each time with the gas cap off and it drove just fine. I did have an ’86 fj60 back in the early ‘90’s that had a similar problem and I replaced the fuel filter and the fuel pump with no change. Went to a shop and the mechanic who had fixed it told me it was a venting tube off the gas tank. That truck did not have the recall maintenance on the fuel tank performed. Can anyone give me any direction as to this issue? Thank you in advance.

 

[Elbert]

maybe someone else can chime in but is there a hard line on the firewall in somewhat close proximity to the heater hoses....where a rubber vacuum line connects and then runs to the charcoal canister...I think this is the actual vent for the gas tank. Its part of the emissions crap so if you have to pass emissions you may have some issues , but you need to make sure the vent process is still working.

I did an engine swap and my charcoal cannister is long gone and that metal hard line is just vented to a long rubber hose running over into the fender well. I don't have emissions testing where I live.

 

[60Man]

Thank you Elbert. I did take a look at the charcole can and looked at the hard line on the fire wall. It looked like the like was fine. I was able to blow air into it with out any problem. However when I was under the hood I noticed to lines under the air cleaner that were disconected. I posted a photo of the two lines and I pluged them back in, was sure to put the gas cap back on hand tight, and put 5gal of gas in and drove it around this morning without any problems. This might do it. Thank you for the help.

 

[Elbert]

when my truck was stock I had issues with filling the gas tank (overflow) which I think was a result of poor venting. Now with engine swap its not as bad but you have to watch the flow of gas into the tank.

in regard to vapor lock issues..tank vent would be an issue to look at... but I think you should also make sure your carb fan works. Apparntly vapor lock was / is a known issue with the 60 series.

You may be good to go now. All those magical vaccume lines need to be connected and functional..

 

[iowaguy]

gas cap issues

So I have a question about the vapor separator on my ’87 fj60. This has had the recall preformed back in ‘97. I think I am experiencing some problems with the venting of the gas tank, or vapor locking. The truck has 125k and it is all OEM. I just started to experience some vapor locking symptoms. Some bucking at low RPM with a fuel tank of less than half full, and some difficulty starting after the engine is hot. I am not convinced that it is vapor locking because it has been starting with less than 5 miles into the drive and it just started in the cooler weather of late September in Buffalo NY. Today I drove the truck twice for about 6 miles each time with the gas cap off and it drove just fine. I did have an ’86 fj60 back in the early ‘90’s that had a similar problem and I replaced the fuel filter and the fuel pump with no change. Went to a shop and the mechanic who had fixed it told me it was a venting tube off the gas tank. That truck did not have the recall maintenance on the fuel tank performed. Can anyone give me any direction as to this issue? Thank you in advance.

i took the gas cap off of my 85 fj60 with the same issues. i busted all the stuff off the underside of the gas cap save for the rubber seal, and alleviated the bucking/stalling concerns. This of course after i had a new fuel pump put on and fuel filter exchanges. hope this helped.

 

[Spike Strip]

The two lines that go to the top of the charcoal canister, switch them around and see if it goes away.

And is your carb fan working ?

 

[60Man]

Funny you all ask about the carb fan because I was under the truck this morning looking at the sensor on the cat. In reading on the carb fan I found that just cleaning the sensor with some WD40 and looking at the ground contact to make sure that all is well. That will be the next thing that I do. Thank you all...

 

[60Man]

So an sad update. I have been driving the truck for the last week or so with no problem. I put about a half of a tank of gas in and the problem came back right away. I drove it around for a bit and found that it is happens mostly at low RPM when I need a small amount of gas. If I step on the gas the truck will do okay. Then when I take my foot of the gas and idel the problem comes back. So I parked it and kept it running, opened the hood, and can hear the motor run ruff. I looked at the hoses again and all are right. I swiched the hoses on the charcoal can and no good. Still with the motor running I removed the gas cap and a very big swoosh. Motor still not running well. So I shut it down and put the hood down and the gas cap on. Started to work on something and then came back to it about 10 min latter. Now the motor has been off for 10 min and I put the gas cap on after the motor was off. I removed the gas cap for a 2ed time and again a big swoosh. How can that much build up so soon when the motor is not running?

 

[FJ40Jim]

RFG has high RVP. Has nothing to do with engine running.

Sounds more like there is dirt floating around in the carb, obstructing the slow jet. There is enough fuel flow for idle, but not enough to transition above idle. And the main circuits are clear, because it runs OK when the pedal is used more aggressively.

 

[60Man]

So the slow jet in the carb? Well I am not very well trained in working on carbs. I have worked on mostly small motors. I have been doing some more reading on some other threads and it looks like the work is something I can deal with. Let me first say that as I was looking around the carb and the motor I have noticed a small leak in the EX. manifold. I did not look like anything big, just a small amount of spiting sound. Can it be that it is not the carb and the leak in the manifold is playing around with the vacum. Or do I just need to take the carb off and give it a good cleaning? If so I will ask if anyone can point out the slow jet on the carb?

 

[FJ40Jim]

The slow jet is clearly identified in the exploded view in the manual.

 

[60Man]

Thank you to all who helped.. The end to this tail is easy and somewhat bone - headed on my part. It turned out to be the fuel filter. Fixing cars 101 Start with the $8 part that takes 1 min to change in the parking lot of the auto store. Thank you again to all.

 

[Spike Strip]

Yeah, they kinda fill up after 25 or so years...

 

[60Man]

So I am back with the same issue almost to the year. Is it likely that the filter is shot again. I will change it to see but if anyone has a thought on how the filter can get junked up after only 1500 miles I would love to hear it. Thank you again.

 

[FJ40Jim]

The filter can fill up in 5 miles if the tank is rusty inside or the gas is dirty.

Remove the filter and knock the inlet side on a piece of clean paper on the floor to see what comes out. Proceed from there.

 

[60Man]

Thank you Jim. I will give it a try. I did look into the gas tank recall and my truck did have it done. But we will see what comes out.

 

[Stumpalama]

You can also autopsy the filter by cutting it open, if it is the plastic type (are the 60 filers the same as the later 40's of more like the 62's).

 

[FJ40Jim]

Filters are the same in equivalent years. i.e '83 FJ40 & FJ60= same.

 

[scott76f]

The two lines that go to the top of the charcoal canister, switch them around and see if it goes away.

And is your carb fan working ?

I'm having a similar problem with an "82 60. Swapping the lines will do what and why would that alleviate the problem? Fresh carb rebuild 6 months ago and has started flawlessly hot or cold until just recently. Just want to make sure i understand before I try. Thanks again.

 

[OSS]

I'm having a similar problem with an "82 60. Swapping the lines will do what and why would that alleviate the problem? Fresh carb rebuild 6 months ago and has started flawlessly hot or cold until just recently. Just want to make sure i understand before I try. Thanks again.

There's a check valve that sticks shut on the Tank pipe of the charcoal canister. The other Purge pipe doesn't have one.
Swapping the hoses allows the tank to breathe freely through the canister instead of getting blocked off by the sticking check valve