Evaprative system help

[hootmmc]

I have an 86 F150 2wd with the 302 EFI. I have had some gas fumes in the engine compartment when the engine is warm , and slow starting ( like flooding)
I wondered why the evap canister is connected directly to the throttle valve.
Now that I have a parts book I found the control valve and solenoid valve . I even have the parts. But my shop manual and the parts book illustrations do not show the set up. Can anyone post a diagram or refer me to one. I know everyone likes to get rid of this stuff, but I would like it to work.
Thanks

 

[Twiceblown351]

Why have it work?? it doesn't help the engine in anyway. Doesn't really help the air we breath. you just let it out when you put gas in the truck. Its EPA BS that never worked.
Put a cap on the hose and called it a day. Or at less do it to see if it fix the truck. and if it does you can fix it or not. that be up to you.

 

[Fellro]

If it smells and acts like it is flooding, then it likely is. The emissions should not really give a smell, it only is to take care of what evaporates when the truck sits. You need to take the air cleaner off and look down the carb to see if it is dripping when you park. The evaporative emissions will do nothing for this situation. It is more indicative of either a heat soak, sticking needle/sinking float, or float adjustment condition

 

[jebadiah04]

Ok. So I can't find a diagram but I can break down the basics of the evap canister for you.

basically all that is happening is the fuel tank is vented to the charcoal canister to scrub out the stank and fumes. From there it runs to the intake so the motor will burn up and Un burnt gas vapors.

Ad for hard starting and flooding when warm? My 85 efi 302 did that too. Turned out to be the fuel pressure regulator. Strange they only do it warm but my theory is the valve dies and the pressure becomes too high. Then when the hot engine heats up the fuel it expands it. The fuel pressure spikes and when you turn the key on to prime the engine it gets was say to much fuel. The only way to start it is to keep cranking until the pressure bleeds out and it stops flooding itself.

at least that is my theory.

another theory I have is that you could have injectors sticking. But I'm 99% sure your evap system is not causing flooding...since a lot of people remove them anyways like you said. Mine is still in tact so I can take pics for you if need be but I'm not 100% sure what you are looking for

I am not sure of an solenoids or any thing else that's a part of this system.

 

[jebadiah04]

Why have it work?? it doesn't help the engine in anyway. Doesn't really help the air we breath. you just let it out when you put gas in the truck. Its EPA BS that never worked.
Put a cap on the hose and called it a day. Or at less do it to see if it fix the truck. and if it does you can fix it or not. that be up to you.

Emissions laws and it's an explosion resistant system is its intended purpose since there is no other vent on these things. Does it work? Meh probably not. Ain'thurting anothing either. Plus some guys go for 100% original and factory function.

 

[jebadiah04]

If it smells and acts like it is flooding, then it likely is. The emissions should not really give a smell, it only is to take care of what evaporates when the truck sits. You need to take the air cleaner off and look down the carb to see if it is dripping when you park. The evaporative emissions will do nothing for this situation. It is more indicative of either a heat soak, sticking needle/sinking float, or float adjustment condition

86 302s are EFI

 

[Fellro]

My mistake. Then it would be possibly a leaking injector. Either way, evaporative emissions especially will not be the source of the smell. The regulator may be leaking into the vacuum line. Take the vacuum line off the regulator and see if there is any gas in it. On injected vehicles, the evaporative emissions only collects from the tank and dispenses into the intake once the engine is fired up and warmed up.

 

[jebadiah04]

After more research this is what I found.


The solenoid is usually shut unless the engine is idling. Then the computer will open the evap solenoid and pull the stored vapors into the engine to be burnt. This stops vas gators from escaping into the atmosphere as you drive. I guess these systems help a lot with smog since smog can be caused by raw gas fumes as well as exaust. Anyways if the solenoid fails in theory it could start pulling vacuum 100% of the time and causing the e fine to start ducking gas vapors all the time. Which could cause a rich condition and flooding. I guess this is fairly common.

However I am not 100% sure where the solenoid is since I've not messed with mine before but from what I've read you should be able to follow the vacuum line off the intake back to it or crawl under the truck and follow the steel vent line to the canister.

Even though i highly doubt the evap system is causing your problem it appears to be possible. Still would check fuel pressure first.

 

[Twiceblown351]

There a rubber hose coming from the upper intake,it comes along topside the right valve cover to the front of the engine.by the intake heater hose you will see it. it goes right to the EVAP can on the side of the inter fender under the Battery. In that rubber line by the heater hose will see a Valve with wires going to it. That the valve your talking about. Take the hose off the intake and put a plug on it. Plug it up. And try to drive it for a day. See if it fixes it?? then you can do with it as you will.

I dont think its what wrong with your truck as Fellro said.

Put a Fuel PSI on the fuel rail. It should be 40PSI at idle with the vacuum line on the FPR.

86 Right?? 2 tanks?? IS your one of the ones with 3 fuel pumps?? one is each tank and one high PSI pump on the frame rail?? with a tank Valve??
there kind of bad about killing one of the pump but still running.

and you got fumes in the cab? starts hard? its rich. high fuel PSI [ Bad FPR]. Bad Injector. fuel in the vacuum port of the FPR[Bad FPR]
Low spark. could need tune up. Bad map sensor. leek in line to map sensor.

 

[jebadiah04]

No map sensors on speed density trucks. I'm with twice blown tho. Plug it off and see if it helps. Check fuel pressure then Injectors. Or maybe you have a leak on your fuel filter. It's right under the cab

 

[Twiceblown351]

explosion resistant system is its intended purpose since there is no other vent on these things.

explosion resistant system!! no not even close.

There is way more then one vent for the tank in the system. Its not a Carb truck there doesn't need to be one on the engine at all. the other one have a one way check valve on the tanks. and one going to the fuel caps.

Ive fix the EVAP system on new car and got rid of it on other cars
. and my own cars that i own that do not have the EVAP system on them any more do not smell like gas ever.
A missing EVAP system on a car when you know how to get rid of it does not make a car or truck smell like a gas can inside or out. or make it less explosion Resistant,

 

[jebadiah04]

Never said it actually did anything. just said it trapped vapors

unhook in it and not plugging it off could equal BOOOOM

 

[Twiceblown351]

No map sensors on speed density trucks. I'm with twice blown tho. Plug it off and see if it helps. Check fuel pressure then Injectors. Or maybe you have a leak on your fuel filter. It's right under the cab

Yes speed Density cars and truck have a Map sensor.. what that do not have is a MAF sensor.

The MAP sensor is that black box thing up on side of the heater box on a steel braket with a rubber hose going to it from the upper intake. with a 3 wire plug going to it. Its what tell the computer the load on the engine. with out it your computer and engine would be lost.

 

[jebadiah04]

I stand corrected. I was thing maf

 

[Twiceblown351]

Never said it actually did anything. just said it trapped vapors

unhook in it and not plugging it off could equal BOOOOM

Please dont say its going to go boom. Your on here asking Q&A about something you dont know anything about. Or you wouldnt be asking about it at all.
So now you talking to more then one person that know why it work how it work and why its there. and fixes they for a living.
But your still saying it will go boom But dont understand why or why not it would or could go boom.
Please if you know all about it all please dont ask why or how it work in the first place.

Sorry im not a know it all but when i talk . i talk about things i fully understand and have been working and fixing for over 25 years. with full training.

The truck or gas tank will not go boom anymore with or with out a EVAP system.
I know the truck inside out. Ive have had more then one torn down to the frame rails.
and are trying to help you fix something that you dont know everthing about. Thats why were all hear.

Thank you. good luck with your repair.

 

[jebadiah04]

I'm not the one asking for help there speedy. I'm simply saying that if the original poster unhook his shit and doesn't plug it off it can and will allow gas vapors to exit the tank and flow into the engine compartment. Let me spell it out for you...

If he blows up or catches fire to his truck based on your advice who gets blamed?

Ftf

if he removes emissions equipment it becomes a federal offense so stop giving illegal advice. I want Ftf to be here for years to come. You aren't the only person on here who has torn down one of these trucks.

Let me school you a little on chemistry. Do you k ow what the flash point of gasoline vapor is? 536 F. Do you know how hot exaust leaving the heads is? Let's forget that and simplify it further. Ab exaust manifold...cast iron...it idle is anywhere from 460 F to 520F. Let's think about what happens when you drive it. The Pyro in my truck reads over 1500 degrees some times. Now let's take gas vapors (which has a flash point of what again?) And apply them to exaust manifolds...what happens. You can't tell me in all the years of you stripping down trucks to the frame you have never seen gasoline vapors ignite. I have sometimes it's neat sometimes it's frigging scary.

so before you go saying...just rip it off!!! You don't need that!!! Think about the consequences of your words. This dude could be 15 years old with a truck that has no header gaskets left in it. Let's not purposely apply a fuel vapor escape point to the engine compartment.


You are 100% correct in saying it won't make the truck smell. I know that. But you have to make every attempt when giving advice to do it right.

 

[Twiceblown351]

I'm not the one asking for help there speedy. I'm simply saying that if the original poster unhook his FTF and doesn't plug it off it can and will allow gas vapors to exit the tank and flow into the engine compartment. Let me spell it out for you...

If he blows up or catches fire to his truck based on your advice who gets blamed?

Ftf

if he removes emissions equipment it becomes a federal offense so stop giving illegal advice. I want Ftf to be here for years to come. You aren't the only person on here who has torn down one of these trucks.

Let me school you a little on chemistry. Do you k ow what the flash point of gasoline vapor is? 536 F. Do you know how hot exaust leaving the heads is? Let's forget that and simplify it further. Ab exaust manifold...cast iron...it idle is anywhere from 460 F to 520F. Let's think about what happens when you drive it. The Pyro in my truck reads over 1500 degrees some times. Now let's take gas vapors (which has a flash point of what again?) And apply them to exaust manifolds...what happens. You can't tell me in all the years of you stripping down trucks to the frame you have never seen gasoline vapors ignite. I have sometimes it's neat sometimes it's frigging scary.

so before you go saying...just rip it off!!! You don't need that!!! Think about the consequences of your words. This dude could be 15 years old with a truck that has no header gaskets left in it. Let's not purposely apply a fuel vapor escape point to the engine compartment.


You are 100% correct in saying it won't make the truck smell. I know that. But you have to make every attempt when giving advice to do it right.

First off i never told you to rip it off. I told you you can get rid of it IF IF you know what you are doing. I told you could amp to get rid of it or fix it. And it was up to you.

So know you want to talk about Flash point and all that junk. Fine. Yea i know i under stand it alot more then you do.I work with E85 and C16 race fuel about 2 days a week. Flash point of that is much lower then pump gas.

Have you ever look to see were the vent is on the EVAP is on that truck your working on?????????????????????

Oh look Its right there on the EVAP can under the Battery and next to the HOT AS HELL HEADER. And You want to talk about safety???

If your Pyro on your truck reads over 1500 degrees some times. on a gas engine with out a power adder truck or car,
Theres something way wrong with it. and its about to melt a piston down.

No in 15 years of building fixing and racing some nut case car and truck. Ive never had a fire, Its called Safety!!! With fuels like E100 E85 C16 C23. Nitro.
C16 has a 90% evap @ 215.8°F. A lot less then pump gas.

As for the EVAP being removing emissions equipment and its becomes a federal offense. Thats not true as long as it not a 2000 or newer.
this is what the EPA has on there web site.

When is EVAP required on cars and trucks?
EVAP is required on 40% of 1998 model year cars, 80% of 1999 model year cars, and 100% of
2000 model year and later cars. Light-duty trucks have a six-year phase-in period, starting in model year 2001

But you would have to be into cars,Fix them everyday, And understand how and why things on cars and truck work and why they,re there and how it all work together.
But Please tell us all how it works. Since you know all about it. have training. And dont need any help with this repair.

 

[hootmmc]

86 evap system

Looks like I stirred things up. I did wonder about a leaky injector , but the truck can sit for weeks and fires instantly, and I not heer the high pressure pump run if turn the key when it is cold. I did have the injectors out to clean them it ran fine at first. This is the first EEC engine I have worked on so the control system is new to me. If anyone has any other thoughts I would love to hear them. Thanks