60 series fuel tank venting HELP ????

[Beehanger]

Until you get it figured out—
Remove the gas cap and stuff a rag in the fill pipe and lock the access door.
That will eliminate any vapor pressure in the tank & lines and vent it outside.
My guess is your vapor separator behind left rear panel is still leaking and your charcoal canister check valve is stuck (unfixable).

How can you fix a vapor separator leak? Already replaced charcoal canister so wouldn’t be that

 

[OSS]

wouldn't that be passenger side rear panel? at least that's where it is in my '87

Yes! My mistake!

 

[OSS]

How can you fix a vapor separator leak? Already replaced charcoal canister so wouldn’t be that

They leak at hose junctions or if it has a crack

 

[Beehanger]

You need to read the emissiosn diagrams for charcoal canister. If all of your lines are connected correctly and unbroken from tank to separator, then you need to test your charcoal canister, vent control valve, VCVs and associated lines are routed correctly. Then come back.

View attachment 3508991
View attachment 3508992

Make sure all lines are clear,

Would being desmogged change the routing?

 

[Beehanger]

They leak at hose junctions or if it has a crack

Can you buy replacements? I’ve also heard of people taking wires to em to clean out junk that gets stuck in there

 

[mattressking]

Would being desmogged change the routing?

No, smog/emissions equipment is separate. An effective desmog retains HAC, EVAP, HAI, Decel Fuel Cut switch, choke opener and choke breaker.

EGR and Air injection are their own systems and do not rely on above and vice versa.

 

[Beehanger]

Until you get it figured out—
Remove the gas cap and stuff a rag in the fill pipe and lock the access door.
That will eliminate any vapor pressure in the tank & lines and vent it outside.
My guess is your vapor separator behind left rear panel is still leaking and your charcoal canister check valve is stuck (unfixable).

Hey mate, can you drive with a rag stuffed in there? I’ve also heard of punching a hole in gas cap.

FYI: on this rig, I’ve pulled gas cap off to fix venting issues, and accidentally left it off on a hot day in my driveway and it spilled petrol everywhere just sitting there. (no rag, not sure if this helps)

Does this clarify anything or prevent me from doing the rag trick?

 

[mattressking]

Hey mate, can you drive with a rag stuffed in there? I’ve also heard of punching a hole in gas cap.

FYI: on this rig, I’ve pulled gas cap off to fix venting issues, and accidentally left it off on a hot day in my driveway and it spilled petrol everywhere just sitting there. (no rag, not sure if this helps)

Does this clarify anything or prevent me from doing the rag trick?

Don’t drive with a rag stuffed in, you absolutely can but I only recommend folks who know exactly what they are doing, too many people can start fires this way because of negligence or just plain ignorance.

Check all your hoses, in/out, test what I told you to test and then circle back. Stop guessing

 

[Beehanger]

No, smog/emissions equipment is separate. An effective desmog retains HAC, EVAP, HAI, Decel Fuel Cut switch, choke opener and choke breaker.

EGR and Air injection are their own systems and do not rely on above and vice versa.

3 questions:

If I have headers how do I maintain HAI and HIC

How can you check if line from under the truck going from fuel tank to canister ain’t plugged?

Side question: What happens if you deleted HAC on your desmog (can you compensate with a tune at altitude change?)

Thanks,
Dan

 

[mattressking]

3 questions:

If I have headers how do I maintain HAI and HIC = You can't without a little work - I'm stating based on a stock engine. It isn't necessary, just an option to retain.

How can you check if line from under the truck going from fuel tank to canister ain’t plugged? You need a compressor with air to fill the line and test flow.

Side question: What happens if you deleted HAC on your desmog (can you compensate with a tune at altitude change?) Only by manually adjusting the distributor to compensate is all you can do. This assumes the advance diaphragm still works on your truck.

Thanks,
Dan

 

[OSS]

1. Your HAI and HIC are gone with headers.
2. EVAP system integrity is usually checked at a shop by blowing smoke back through the lines starting in the engine bay.
3. HAC when operational, advanced the timing 7° AND leaned out the fuel mixture. You can easily bump up the timing your own but leaning out the mixture properly would require smaller jets in the carb. You can’t just leave a vacuum hose unattached and hope that it’s right.

 

[Beehanger]

1. Your HAI and HIC are gone with headers.
2. EVAP system integrity is usually checked at a shop by blowing smoke back through the lines starting in the engine bay.
3. HAC when operational, advanced the timing 7° AND leaned out the fuel mixture. You can easily bump up the timing your own but leaning out the mixture properly would require smaller jets in the carb. You can’t just leave a vacuum hose unattached and hope that it’s right.

So since I have no HAC, I could get away with advancing timing about 1 degree and htats about it? I dont want ANY vacuum leaks, even the intentioanl ones from toyota correct? shooting for 15 mercury when I start tuning and doing the lean drop method. I have no issues adjusting the carb if I head up a mountain pass.

Dan