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purge valve and stored vapors

  #1  
Old 10-30-2018
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Icon5 purge valve and stored vapors

This is in regards to a 2007 Ranger, 4 liter four wheel drive vehicle. I have some questions about the purge valve, and the stored vapors in the E V A P system.

I know that when the engine gets to a proper operating temperature, the purge valve which is normally closed, opens and requests the stored vapors from the charcoal cannister, to be reburned in the intake manifold.

I have successfully modified my system, having removed the cannister and dust collector. The vapor hose from the fuel tank is connected to the normally open solenoid that used to be attached to the cannister. The other end of the solenoid, has the curved hose on it that was taken from the dust collector. You might see more detail from this picture.

Per this modification, I no longer have a cannister storing the vapors; which in essence, are released to the atmosphere, through the normally open solenoid. Since vapors are no longer being stored anywhere, how does the purge valve work? --Does the computer still open the valve and request for hte vapors through the front end of the vapor hose? Or, does it some how sense/check for vapors, and when it doesn't find any; does it continually leave the purge valve closed?

Would I need to reprogram the computer to not 'purge' vapors? Or, would I just disconnect the wires and put a resistor on the pins in the connector?
 
  #2  
Old 10-31-2018
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Without the canister vapors are stored in the gas tank
Shouldn't be a problem unless you overfill the gas tank, so don't

The Charcoal Canister is used to hold gasoline vapors after engine is shut off, then when engine is started the purge valve will open to pull those vapors into the engine.
The charcoal absorbs the vapor then releases some as vacuum air flow is applied
If canister is not present then system is pretty much sealed, there is a Vent solenoid that is usually only used by computer to test the EVAP system, it opens to allow fresh air to be pulled into the system
 
  #3  
Old 10-31-2018
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okay ron. thank you. to confirm my understanding you; are you saying that without the cannister and its assembly, the purge valve gets its vapor from that which is in the fuel tank?

then, knowing that the solenoid in my remaining assembly is usually open, what is it that 'escapes' through it per my modification in the picture i posted? is vapor still being pulled through that to a non existent cannister? but in this case, to the outdoors?

i would imagine then that when the purge valve is pulling the vapor from the fuel tank, would the solenoid at that time be closed? --how does it all work per this modification?
 
  #4  
Old 10-31-2018
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Diagram here of EVAP system: https://www.aa1car.com/library/evapobd2.gif

In your setup Purge Valve is hooked directly to the gas tank, so no fresh air inlet/outlet unless you hooked up, "T"ed, the vent hose into the line as well
 
  #5  
Old 10-31-2018
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well ron, im only guessing here, that per your tee comment, my modification, according to this picture here;

that the air inlet/outlet would occur per the normally open solenoid. this new image, outlines the vapor hoses connected to the purge valve. one going to the intake manifold, and the other going to part of the hose attached to the fuel tank and the cannister (solenoid).

in the image, the purge valve is at the blue dot. the fuel pump connection is at the red dot. the green dot is the connection at the back of the tank. and the black dot shows where/how it connects to the cannister. the black line illustrates the black dots connection to my modification. the majority of the hose from the valve to the back of the vehicle, seems to have more of a direct connection to the cannister than the fuel tank; if you follow closely its separation from the two sectons going to the tank. though these two do still have joints to the main hose. but per the image here, it seems it could still get fresh air at my modification; being that the solenoid is normally open.

What do you think?
 
  #6  
Old 11-01-2018
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If you just have a single hose to the Canister, then just cap that hose, if however canister also has a Vent hose then connect both hoses together
 
  #7  
Old 11-02-2018
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okay ron. i have modified my E V A P system, leaving only the solenoid. i do not have a cannister, or the dust collector. all i have is the vapor hose from the fuel tank directly connected to the normally open solenoid. the other opening of the solenoid has a short rubber hose without a cap connected; as you should see from my original attached picture.

the hose all this is connected to, is almost an uninterrupted length making a connection to the purge valve. about two feet away from the solenoid mentioned above, this same length of hose has two connections adjoining to the fuel tank; as you should see in the illustration image i attached previously.

so, i dont have a cannister. and these two separate connections to the fuel tank, i know not what their purpose is. if you know that may help in your next reply

i currentely have no issues with anything or any diagnostic trouble codes, but i am curious how the purge valve would work in my current modification' as i am considering also removing it.

do let me know. thank you.
 
  #8  
Old 11-02-2018
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Not sure what you are after here?

There is no sensor for canister so it can be removed, as long as system is sealed during operation all will be well
You will be venting more vapor since it isn't passing thru the charcoal, but that's your choice, lol, polluter

If you are asking what hoses go where and why, you would need a 2007 Ranger EVAP reference
The EVAP systems are basically the same on all vehicles but how "they" plumb them is different, even one year to the next

Instead of allowing gas vapor to pollute the air, "they" seal the gas tank while driving, sloshing gasoline causes more vapor, and suck(using engine vacuum) vapor from the tank and add it to the vapor already in the intake(from fuel injectors).
Since "they" loose the vacuum when key is off they added a charcoal canister to collect any vapor when vehicle is just sitting.
Charcoal canister is not integral to EVAP just makes it less polluting.

Like a CAT converters, engines run fine without them, just pollute more
 
  #9  
Old 11-04-2018
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well i guess i was really wondering if the purge valve has a sensor in it. or, if the computer is programmed open the valve at certain times. since i am releasing all the vapor to the atmosphere, theres no vapor for it to purge that it would normally be taken from the cannister; which i dont have anymore.

but, depending on the computer, i do wonder if i would be able to safely remove the purge valve and related hoses, and avoid dagnostic trouble codes after putting caps on ports.
 
  #10  
Old 11-04-2018
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There is a pressure sensor on the gas tank most likely in 2007

The gas tank is open to air when key is off, that's what the charcoal canister was for.

There is no real strategy as far as I know for EVAP, when you start the engine the computer will apply negative pressure to the gas tank, then wait, and watch the pressure sensor
If it holds then it applies pressure to maintain negative pressure in the tank as you drive.

Gasoline is also being sucked out of the gas tank while driving so EVAP doesn't use full vacuum, just a slight negative pressure that will pull vapor to the engine
EVAP does do TESTING and Purge Valve is part of that
EVAP codes can take a long time to clear even after a repair, because you can't force or in any way trigger an EVAP test, there are ways to try and trigger it but it may of may not test


Fords Drive cycle outline here: Ford Motor Company Driving Cycle
And here: https://www.nyvip.org/PublicSite/OBD...-monitors.html
 
  #11  
Old 11-04-2018
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Okay. thank you for your help Ron. About a month ago, my malfunction indicator light came on. I figured it was due to my emissions system modification. I bought a cheap scan tool at walmart, and it showed that I had a small leak. Though I couldnt test for the leak, I was almost sure where it could be. I addressed it, and after driving maybe 50 miles or so, the light did go out. But after about 40 miles of driving, maybe more; i used the same tool. It still showed the small leak diagnostic code. --though, during the time of the light coming on and scanning, while it shown a total of only one code, it showed the same code, but twice. one of them was pending. with this most recent scan, it wasnt a 'pending' code, but still apeared, yet the malfunction indicator light was off.

Do you know how long until the computer clears past, post-repair codes? I know I can use the tool to clear the codes, but that also deletes a buncha other things that i'd rather not mess with.

....and then, what about the instrument panel test, and its display of diagnostic trouble codes? its the test that occurs when holding in the trip meter button while turning the ignition to on. it tests guages, indicator lights, and shows a bunch of other computer data. part of the process has it 'display' any diagnostic trouble codes. --both while i had the malfunction indicator light iluminated and after the repair and the lights going off; i did the instrument panel test, and it continuously shown a total of zero codes. what is the purpose of that part of the test?? i do recall not long ago, going through the test, and it shown that i had 1 code, but i had no way to scan the system.
 
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Old 11-05-2018
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Pending codes are just that, they don't activate CEL unless that specific code is repeated at least 1 more time, sometimes 5-10 more times, that's up to Ford software programmers
And if pending code is not repeated in says 30 drive cycles then it will be cleared, again number of drive cycles is set by original programmer of the software.
A lot of software updates are because of glitches in the pending code resets, CEL would come on when nothing was really wrong, so update would lower drive cycles to 3 and then clear pending code, so no CEL if it repeated over and over, just a glitch that caused it to set to begin with.

The instrument panels in 2004 and up Ranger were run by microprocessors, this was to prevent odometer "roll backs" that were common on Fords, people would swap out instrument clusters to one with lower odometer mileage and then sell vehicle for more money.
These newer instrument clusters are "married" to the computer, and visa versa, so if you unplug instrument cluster engine would not start, if you replaced it, engine would not start
Not even a Ford Dealer can swap instrument cluster(or computer) on their own, Dealer notifies Ford head office of the need to replace instrument cluster(or computer), Dealer gets actual miles from odometer in cluster AND odometer in the computer, yes computer also has odometer reading.
Ford head office programs new instrument cluster(or computer) for correct mileage then sends if off to the Dealer for swap out.

Anyway the point is the instrument cluster can show B codes, body codes, and some P codes, Power train codes, but it is not very reliable for P codes, and even B codes should be confirmed with OBD2 reader

Small leaks in EVAP system are common, filler and vent tubes are most likely location for leaks, also gas cap gasket
 
  #13  
Old 11-05-2018
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i see on the clearing of codes. but, what if the code i see in the scanner isnt pending, yet the malfunction indicator light is off? i scanned it a few minutes ago, and it shows the same 'small leak' code for emissions. the light itself had been on for maybe 2 weeks, and went off early last week. when it was on, the scanner showed the same code twice, but one was pending. but now, the pending is gone and the light is off. could the leak be due to there now not being a cannister to send vapors to; as they are now being let out into the atmosphere?? --and just 'leaking' through the normally open solenoid. is that really a leak?

and then, when i take it in to the dealership for its usual multiple point inspection, do they normally connect their scanner to the data link connector? and, if they do, and their system identifies the same emissions trouble code; would they immediately investigate to see if things are alright where the emissions assembly should be, but isnt?? or would they just let me know after their done with normal things; that i have a small emissions leak?

i havent had an 'update' for maybe 10 years. that was the last time that light came on. they checked and said that i needed an update. i have no way presently to simply download and install any updates.

regarding your statement on disconnecting instrument clusters and engine not starting... about 4 months ago, i had unplugged the instrument cluster (removed from the cabin) to check the lights in it. everything checked out and i plugged it back in. since then, ive had no problems starting the engine or driving. thats strange.

well my instrument cluster, in test mode just shows dtc and then a single digit number. in the past that number has been 0, but lately and even today, the number is 1. it shows dtc 1, and blinks a four digit number of 9868 until i press the tripmeter button for the next test. that part of the code test, only shows digits, there are no code prefixes of P C B or N. do you know what that could be?

9868
 
  #14  
Old 11-05-2018
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Engine won't start while instrument cluster is unplugged, unplugging it doesn't hurt anything, same as unplugging computer doesn't hurt anything
The instrument cluster has a unique ID number, as does the computer, each needs confirmation from the other on startup/powerup or engine will not start


A code in memory, pending or set, doesn't mean CEL will come on, CEL is to notify driver that there is a problem that needs attention, small EVAP leak isn't an immediate problem so no CEL just something computer wants to keep in memory.
Ford dealer may check for EVAP leak, but tech would look it up using Ford data base and VIN and could be a "no don't bother" code, meaning computers software and installed EVAP system will often show that code with no actual problem, so they may or may not clear the code, and may or may not investigate

Instrument cluster codes are not reliable, if they are valid they will be in computers memory
DTC 0 means no codes stored
DTC 1 means 1 code stored
9868 is most likely an airbag code
Ford doesn't release much info about these odometer codes, usual response in Shop Manual is to read full OBD2 codes with Ford scanner
Known example is B1364 9364 Ignition Start Circuit Open
B1364 is an OBD2 Body code
9364 is the Odometer code

So if we do that to 9868 we get B1868 which is airbag light issue, whether there is an airbag light issue or not is unknown
 
  #15  
Old 11-05-2018
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oh, i see regarding the instrument cluster situation. thank you.

ill be going to the dealership in a few weeks for a regular check up. per your experience and knowledge, if they physically investigate, seeing the code, and notice my modification and there not being an E V A P assembly by the spare wheel; could they maybe deem the vehicle 'illegal' to drive (pollutant hazard) and 'prevent' me from driving it away?

and, arent there more expensive and professional scanners available for public purchase that can remove the code, yet not harm the other data, like computer 'learned strategies'?

if the code is deleted, and maybe in fact there is no leak and its just a matter of time for the computer to delete it; would the computer not post another trouble code until there really was a detected leak?

then, with the normally open solenoid back there, and no cannister to store vapors, could the computer detect that as a leak with vapors 'leaking' into the atmosphere-cannister.

i actually do have the two volume ford workshop manual, and long ago checked it for codes, and didnt see the 9868 thing in there. but thats wierd that it could be tied to the airbag. ive not had any issues with the airbags. and any 'tweaking' ive done in that area, they were properly depowered and repowered; per those books. and about three months ago, the dealership finally replaced the inflator on the passenger bag. thats interesting.
 
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Old 11-06-2018
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It depends on state law standards, look up your states EVAP tampering laws
Some states require any work by Shops must include restoring any emissions system to factory standards for that year, so they may want you to pay to have charcoal canister replaced, but it is a FREE Country, lol, so you can say OK, I will do it myself.

EVAP won't be like Catalytic converter laws though, no or bad Cats must be replaced once discovered, or shop gets $25,000 fine, its a Federal beef, and you can elect to DIY Cats but there is a time period set for re-inspection in most states

The small leak code shouldn't be a big deal, I doubt they will pursue it, but I ain't them
 
  #17  
Old 11-06-2018
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ahh yes, of course. thank you. i did check and according to oregon department of environmental quality, they state that no person may operate a motor vehicle if any element of the factory installed pollution control system has been modified... --decreasing its effectiveness of doing such control.

so yeah, if they talk about having it replaced; i will (eventually) just put it all back in. :)

but anyway, thank you for your input and help here RonD.
 
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