gas tank fume pressure EFI

[73azbronco]

you tree huggers and your canpurge circuit. I love it.

 

[73azbronco]

So this is how I would want to hook it up?

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Hmmmm, might look up the ford fuel injected book from the 80's/90's, i remember this book going for $2-300 back in the late 2000s

https://www.thriftbooks.com/w/ford-fuel-injection--electronic-engine-control-how-to-understand-service-and-modify--all-fordlincoln-mercury-cars-and-light-trucks-1980-1987-ford_charles-o-probst/815403/item/29908013/?utm_source=google&utm_medium=cpc&utm_campaign=low_vol_f/m/s_standard_shopping_customer_aquisition&utm_adgroup=&utm_term=&utm_content=603452145786&gad_source=1&gclid=Cj0KCQjw_-GxBhC1ARIsADGgDjsFhoDukCtysSzYqvBluwRTSTzma_T-0BKkaTiHQvbPpETbu1vu_AkaAsCnEALw_wcB#idiq=29908013&edition=4875511

 

[Broncobowsher]

you tree huggers and your canpurge circuit. I love it.

Doesn't hurt performance
In theory gets you better economy (you get a chance to burn the gas that would normally evaporate to the atmosphere)
Reduces the stink in the garage from gas fumes, which tends to keep plastics and rubber stuff that are stored in the garage lasting longer.

All good reasons in my book.

 

[Big Slim]

i was getting a houling sound out of the gas cap with all the pressure. which cant be helping anything. but all for better for the environment and economy too.

looks like my EVAP was disabled on the ECU.

 

[EFI Guy]

I sometimes mix in what other manufacturers do as well. Work on other stuff as well.
The basics are the same, implementation and naming of parts sometimes changes.

I wasn't taking a dig, I think you did a great job of explaining it. It shows that you have a better concept of the system than some of the "certified" techs that I've worked with over the years. The terminology even changes with the same manufacturer. An example is some years you have a purge valve, other years it's called a vapor management valve.

 

[EFI Guy]

looks like my EVAP was disabled on the ECU.

Are you sure? The only way to really test funtionality if reporting has been disabled is to wire in a light to the circuits mentioned and watch to see if it ever operates going down the road.

 

[Big Slim]

i asked the guy that tuned the ecu and said it was off. said i could turn it back on with quarterhorse. if it is just a 12v signal i could try the light test.

 

[Broncobowsher]

It's actually a ground signal. Keep 12V applied to one side of the test light, the ECM will choose when to apply ground.

 

[Big Slim]

hooked it up 12v to light and to green/black wire. didnt see it go on. idled it for a good 10 min and was up to temp. how often does it cycle?

 

[73azbronco]

Doesn't hurt performance
In theory gets you better economy (you get a chance to burn the gas that would normally evaporate to the atmosphere)
Reduces the stink in the garage from gas fumes, which tends to keep plastics and rubber stuff that are stored in the garage lasting longer.

All good reasons in my book.

i guess my sarcasm didnt show, yeah, all good, but also, egr good for economy and power.

 

[DirtDonk]

hooked it up 12v to light and to green/black wire. didnt see it go on. idled it for a good 10 min and was up to temp. how often does it cycle?

It might not activate at idle only.
Are you driving the vehicle? If so, I would leave the light connected and drive it around to see if it comes on.

 

[DirtDonk]

Then again, these guys might know whether that’s a legit test or not. If it will occasionally cycle it idle, then you should’ve seen it and I guess that confirms that it’s been deactivated.

 

[Broncobowsher]

Typically won't purge at idle. Typically needs to be at part throttle cruise.
At idle, adding extra airflow can have a noticable change to the idle. At cruise, you have 10x(?) the airflow through the engine so a little extra from the purge isn't noticable.

Can't say that is how the Explorer logic is, but that is common logic I have seen for years in a bunch of stuff.

 

[Big Slim]

drove it into work today and didnt see the light come on, but cant keep eye on it all the time while driving. ill say the tuner is correct that it is off.

 

[Big Slim]

so if my ecu will not control it anymore, how about a thermal vac switch. then it would only open when the engine is hot. better than always open into the intake tube.
or one of these vac controlled one valve

 

[Broncobowsher]

I have some ideas, and some of this goes off into the theoretical...
Completely mechanical method. Drill a hole in the throttle body just above the throttle blade. 1/8"? Think ported vacuum on a carb. At part throttle the throttle blade is just past the hole, but there is still manifold vacuum. That gets vacuum at cruise. Run that to the purge on the canister. The air inlet to the canister, I am tossed if the regular inlet is fine or it if should be routed to the intake duct between the MAF and throttle body.
It should work, I have never done it that way.

 

[Big Slim]

Here is what I think a mechanical setup might look like.

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[DirtDonk]

The line you're showing with the adapter to the large fitting, venting either to vacuum in the manifold, or "soft vacuum" in the intake tract, can also be plumbed into the medium sized fitting next to the small tank vent fitting.
I thought I'd seen the full vacuum type connected to the medium fitting, while the older intake tract/air cleaner housing method was always to one of the larger fittings.

I have also seen "custom retrofit" setups where the medium one was connected to the air cleaner housings. But that was usually due to expediency and not easily sourcing the larger hose and fittings. Just a spark plug boot and some 3/8 fuel line!
Not factory, but was on a '76 with the newer style canister where the old hoses had been lost or destroyed and they wanted it to pass smog.

Not saying one is mo-righter than the other. Just that I've seen them that way.

Paul

 

[Big Slim]

I would have thought the two larger ports would be the vents before finding the drawing of the canister. Would not need fumes going thru charcoal into the engine. Only to store it before venting. Then use normal size hoses to intake and tank. But if I have the right parts I can try different configurations.


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