Emission system -varying codes!
#1
01-12-2012, 08:59 AM
Emission system -varying codes!
Got 2006 Explorer back fron trans rebuild and probably unrelated but started getting P1405 (Large vacuum leak) and alternating "replace gas cap" errors. When I installed a new gas cap, error went from large vacuum leak -which I checked for on engine and found none using smoke test- to loose gas cap. So next, I changed the emission system valve which is right up front on rt. side of engine looking into engine bay. Now, error has returned to large vacuum leak. So new gas cap and valve. Error does not come back immeditately after clearing. Takes about a week and then either get SES light and large vacuum leak error or just picture of gas cap on dash error. Note that when I remove gas cap, I no longer hear the "whooosh" of releasing a vacuum. Assume now it is in back by spare tire where I need to be looking. I note on emission valve that there is a schrader valve for testing vacuum....Does Ford have a pretty definitive test to pinpoint where offending leak can be found or has someone had similar problem and what cured your issue?
Thanks in advance!
Bill-noob
Thanks in advance!
Bill-noob
#2
01-13-2012, 09:48 AM
Cargo Master
#3
01-13-2012, 10:43 AM
Thank you for the courteous reply. As I said, I replaced the cap with new oem Ford, but I suppose I could have gotten a bad one. Smoke testing whole deal sounds like the plan, but I guess what I did not want to admit is that I don't know exactly where the other system components are located other than they are "in the back by the spare". I don't know whether I approach from the top or underside of the SUV? Don't really know what to look for beyond the filler neck. Is there a vacuum pump to create vacuum in the system, does it take from cars generated vacuum, or does it develope a vacuum from the system being sealed and then gas is pulled from the tank creating a vacuum? If it uses engine vacuum then I could be losing power and all sorts of bad stuff. If It is its own contained unit of vacuum source and venting, then that is better. Any guidance would be appreciated. You can likely see from my sig what cars I do know a little more about :-)
#4
01-15-2012, 05:47 PM
Cargo Master
The fuel cell is a closed system, vented into the carbon canister which then stores the volatile fumes until a prescribed drive cycle. The CPU then commands a valve to open, releasing the fumes into the intake manifold under engine vacuum... Philip
#5
01-15-2012, 06:10 PM
All I see is a blank sig,
The fuel cell is a closed system, vented into the carbon canister which then stores the volatile fumes until a prescribed drive cycle. The CPU then commands a valve to open, releasing the fumes into the intake manifold under engine vacuum... Philip
The fuel cell is a closed system, vented into the carbon canister which then stores the volatile fumes until a prescribed drive cycle. The CPU then commands a valve to open, releasing the fumes into the intake manifold under engine vacuum... Philip
#6
01-16-2012, 10:22 AM
That may not be what you asked, but unless you think about how the system works, you cannot determine why the codes are setting.
As he explained, it uses engine vacuum to pull fumes, which puts the fuel tank under slight partial vacuum. So what happens if there is a leak? The vehicle cannot pull the desired vacuum, and it cannot tell why. My guess is there is a leak int he evap line between the intake and the purge canister. If it was a leak in the gas cap or somewhere between the tank and the purge canister, there would be no lean code, just a gas cap code. The fact that you are getting a lean code or both codes tells me that the leak is somewhere that affects the vehicle whether the purge solenoid is open or not. Unless of course the purge solenoid is leaking, in which case you could have two leaks.
You cannot reliably vacuum test such systems because unless the leak is pretty massive, you will not be able to locate where the leak is. Even if it is massive you still may not be able to find it. But if you take it to a mechanic that has a smoke machine, it should only take a few minutes to find the leak.
As he explained, it uses engine vacuum to pull fumes, which puts the fuel tank under slight partial vacuum. So what happens if there is a leak? The vehicle cannot pull the desired vacuum, and it cannot tell why. My guess is there is a leak int he evap line between the intake and the purge canister. If it was a leak in the gas cap or somewhere between the tank and the purge canister, there would be no lean code, just a gas cap code. The fact that you are getting a lean code or both codes tells me that the leak is somewhere that affects the vehicle whether the purge solenoid is open or not. Unless of course the purge solenoid is leaking, in which case you could have two leaks.
You cannot reliably vacuum test such systems because unless the leak is pretty massive, you will not be able to locate where the leak is. Even if it is massive you still may not be able to find it. But if you take it to a mechanic that has a smoke machine, it should only take a few minutes to find the leak.
#7
01-16-2012, 11:04 AM
That may not be what you asked, but unless you think about how the system works, you cannot determine why the codes are setting.
As he explained, it uses engine vacuum to pull fumes,
I must have missed that. I asked how the vacuum was developed, engine, external pump, or as fuel was used. I did not see that answered. My bad, I guess.
which puts the fuel tank under slight partial vacuum. So what happens if there is a leak? The vehicle cannot pull the desired vacuum, and it cannot tell why. My guess is there is a leak int he evap line between the intake and the purge canister. If it was a leak in the gas cap or somewhere between the tank and the purge canister, there would be no lean code, just a gas cap code. The fact that you are getting a lean code
Did I say I was getting a lean code?
or both codes tells me that the leak is somewhere that affects the vehicle whether the purge solenoid is open or not. Unless of course the purge solenoid is leaking, in which case you could have two leaks.
You cannot reliably vacuum test such systems because unless the leak is pretty massive, you will not be able to locate where the leak is. Even if it is massive you still may not be able to find it. But if you take it to a mechanic that has a smoke machine, it should only take a few minutes to find the leak.
As he explained, it uses engine vacuum to pull fumes,
I must have missed that. I asked how the vacuum was developed, engine, external pump, or as fuel was used. I did not see that answered. My bad, I guess.
which puts the fuel tank under slight partial vacuum. So what happens if there is a leak? The vehicle cannot pull the desired vacuum, and it cannot tell why. My guess is there is a leak int he evap line between the intake and the purge canister. If it was a leak in the gas cap or somewhere between the tank and the purge canister, there would be no lean code, just a gas cap code. The fact that you are getting a lean code
Did I say I was getting a lean code?
or both codes tells me that the leak is somewhere that affects the vehicle whether the purge solenoid is open or not. Unless of course the purge solenoid is leaking, in which case you could have two leaks.
You cannot reliably vacuum test such systems because unless the leak is pretty massive, you will not be able to locate where the leak is. Even if it is massive you still may not be able to find it. But if you take it to a mechanic that has a smoke machine, it should only take a few minutes to find the leak.
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