Removing my EVAP System in it's entirety...
11-18-2010, 02:07 PM
#82
Senior Member
Join Date: Dec 2002
Location: London, ON, Canada
Posts: 595
Prophecy, I don't have the exact codes off-hand, but if you have a small leak code, start with the gas cap. (about $23)
If you have a valve stuck open/closed code, you'll have to replace the release valve at the charcoal tank. (about $100)
However, replacing that valve will likely destroy the charcoal tank, so you'll have to replace that as well. (about $200)
Figure 1 - 2 hours labor for the shop, and you can approximate the math.
With hindsight, if there were someway to cut the valve bolts, rather than attempt to back them out, you could then strap the new valve in against the tank. There's an o-ring on the valve that makes the seal. After which, all you really need is some technique to fix the valve tight... it doesn't have to be the OEM bolts. Be creative, maybe you can get lucky.
If you have a valve stuck open/closed code, you'll have to replace the release valve at the charcoal tank. (about $100)
However, replacing that valve will likely destroy the charcoal tank, so you'll have to replace that as well. (about $200)
Figure 1 - 2 hours labor for the shop, and you can approximate the math.
With hindsight, if there were someway to cut the valve bolts, rather than attempt to back them out, you could then strap the new valve in against the tank. There's an o-ring on the valve that makes the seal. After which, all you really need is some technique to fix the valve tight... it doesn't have to be the OEM bolts. Be creative, maybe you can get lucky.
11-18-2010, 02:17 PM
#83
It should go without saying, but a component to all this is to make sure you are properly tightening your gas cap (even on my new one I have to push firmly in and twist 3-4 clicks) and DO NOT overfill/top off your tank. Once the nozle clicks off, stop!
I recently posted I had replaced my gas cap about a month ago and it resolved my 455 (high leak) code before I was home from Nissan (under 20 minutes). Then, last week I filled up and just "had" to add those .03 cents of gas. I also didn't push in on my new gas cap when tightening.
Filled up again two days ago, didn't top off the tank and pressed in on the new cap. My SES light went off today after approximately 90 miles of driving. Good grief.
Light is back off for now.
I recently posted I had replaced my gas cap about a month ago and it resolved my 455 (high leak) code before I was home from Nissan (under 20 minutes). Then, last week I filled up and just "had" to add those .03 cents of gas. I also didn't push in on my new gas cap when tightening.
Filled up again two days ago, didn't top off the tank and pressed in on the new cap. My SES light went off today after approximately 90 miles of driving. Good grief.
Light is back off for now.
11-19-2010, 05:32 AM
#84
John- that CEL? Same codes as before 
Large EVAP leak, Vent valve stays open
Soooooo I guess I'll be testing my new vent valve per the FSM instructions, or there's a huge split/crack hiding in my charcoal can where I can't see it. The minor crack I've got isn't deep enough to compromise the shell, and I'd also expect a small leak code, if somehow I wasn't seeing its severity.
The more I think about this we todd id EVAP system, the more I'm resigning myself to the fact that my original idea of pulling a vacuum on the pressure sensor isn't gonna get me "outta jail"
If it were that simple, we'd have a single EVAP error code, not the bazillion we do. Guess the ECM does have a specific cause/reaction table that tells it when what it's trying to do does or does not work.....
Oh, and that same B1S2 pair of codes. I wonder why all 4 pop at the same time?......
Large EVAP leak, Vent valve stays open
Soooooo I guess I'll be testing my new vent valve per the FSM instructions, or there's a huge split/crack hiding in my charcoal can where I can't see it. The minor crack I've got isn't deep enough to compromise the shell, and I'd also expect a small leak code, if somehow I wasn't seeing its severity.
The more I think about this we todd id EVAP system, the more I'm resigning myself to the fact that my original idea of pulling a vacuum on the pressure sensor isn't gonna get me "outta jail"
If it were that simple, we'd have a single EVAP error code, not the bazillion we do. Guess the ECM does have a specific cause/reaction table that tells it when what it's trying to do does or does not work.....Oh, and that same B1S2 pair of codes. I wonder why all 4 pop at the same time?......
11-19-2010, 05:57 AM
#85
BlackMacks, I'm sorry to hear your problem continues. And I'm confused why there would be a "vent open" code when you have a new valve. The "large leak" code... isn't that usually a gas cap solution? While that may be true, having a gas cap fail at the same time as all this other crap is highly unlikely.
When my mechanic and I were discussing the EVAP system, he was agreeing that American cars have been built with an EVAP charcoal tank for 40 years, but originally it was passive. It's only been since the mid 90's or so that the system has been micro-managed to the extent it is today with a computer-controlled release valve, purge solenoid, etc.
Anyway, as the familiar phrase goes, I feel your pain. (Oh, look! An unintentional "cigar" segue!
)
When my mechanic and I were discussing the EVAP system, he was agreeing that American cars have been built with an EVAP charcoal tank for 40 years, but originally it was passive. It's only been since the mid 90's or so that the system has been micro-managed to the extent it is today with a computer-controlled release valve, purge solenoid, etc.
Anyway, as the familiar phrase goes, I feel your pain. (Oh, look! An unintentional "cigar" segue!
)
Last edited by Rochester; 11-19-2010 at 05:59 AM.
12-01-2010, 06:22 AM
#86
John- that CEL? Same codes as before
Large EVAP leak, Vent valve stays open
Soooooo I guess I'll be testing my new vent valve per the FSM instructions, or there's a huge split/crack hiding in my charcoal can where I can't see it. The minor crack I've got isn't deep enough to compromise the shell, and I'd also expect a small leak code, if somehow I wasn't seeing its severity.
Large EVAP leak, Vent valve stays open
Soooooo I guess I'll be testing my new vent valve per the FSM instructions, or there's a huge split/crack hiding in my charcoal can where I can't see it. The minor crack I've got isn't deep enough to compromise the shell, and I'd also expect a small leak code, if somehow I wasn't seeing its severity.
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