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C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
All, I have a minor, intermittent problem with fuel smell coming from passenger rear wheel area but only after a multi hour fun drive on a hot day starting with a full tank of gas. Smoke test reveals no leaks and there are no codes. When test program opens the vent valve to relieve pressure from the canister to the atmosphere, it smells like hot fuel vapor, but charcoal should neutralize those vapors right?. So, I believe I need to replace my evap canister. On a 26k mile car, my question is why would the canister be done already? Is something else broken like a fuel level limit valve that allowed liquid gas to get to the canister and ruin it? What parts? I fear it would be the passenger side tank module which is another $300. Does anyone have the related service manual pages or want to sell me a 2011 manual set? I don't want to install a new canister only to have it fail again when I fill up with gas. My friends 2007 z did the same thing after the same drive. I love this car and am only considering fixing it to be perfect. Haven't had smell after I installing dei heat shields either.
All, I have a minor, intermittent problem with fuel smell coming from passenger rear wheel area but only after a multi hour fun drive on a hot day starting with a full tank of gas.
I have experienced this issue a few times at the track. (2009 Z 16,000 miles.) I thought I had a fuel leak so I put the car up on jack stands, removed most of the fuel, and dropped the aluminum pans under the tanks. Did not find anything. Everything I could see was like new.
I do not know where the evap canister is located. I will have to check into this.
The evap canister is above the passenger side fuel tank. The dealer, although very helpful and I would recommend them, wanted $1800. They asked me to reproduce the problem so I took it for an awesome joyride for over two hours after filling up with auto stop. Brought it in hot and they showed me on the lift absolutely no leaks just fuel vapor when venting canister to atmosphere. Hence fairly certain the canister needs replaced...at least?
I know how difficult it is to work on the fuel systems reading threads on here... usually folks doing faulty fuel pump on drivers side. I already got that replaced under special coverage, so not that.
After reading about the crazy complex fuel system, I am curious if/what breaks during an overfill event at the gas station. Does the fill level limit valve FLVV break such that it needs replacing or does it just allow liquid gas upward to destroy the canister during a forced overfill?
And is the FLVV within part 19354814?
I suppose I need a new seal and file level sender if I put the new right side sender in?
Ps. You can find the shields online by searching for dei floor and tunnel heat shields, c6 corvette. I'm happy with them.
On a typical track day at Sebring I drive 3 times with a full fuel tank. I wonder if I am simulating an overfill fuel tank condition with the G forces generated at the track.
It is worrisome smelling fuel vapors after a track session when the car is hot.
Your issue and mine are the only ones I have heard about who have this issue. Please keep me informed if you find any solution.
Not sure how tunnel and floor thermal shields helps this issue.
The heat from the exhaust manifolds and xpipe is deflected downward, whereas without them, I bet the gas tanks get hotter along with the gas inside.
So, the engine is supposed to burn off the excess vapor when commanded by the computer right? And if the car isn't on, the the canister is supposed to capture the vapor but allow the pressure out?
I've actually noticed vapor smell at odd times driving home from the canyon carving, and after the ride being parked in the garage. Could I have a faulty tank pressure sensor or bad solenoid large valve under the hood? Again, no codes, so I doubt it.
Also, fwiw, I bet many if not all corvettes do this. Most people have a cam tune and no cats on here so the cars stink all the time. Not a big deal to those folks. Anyway, hopefully someone knows this issue and can chime in...Im still wanting to know if I should spend the extra $300 and do the passenger side fuel tank module...
Maybe everyone missed my questions with the holiday weekend and all. I'm still trying to figure out if I should replace passenger side fuel tank module, does it break during an overfill event? Sales end today so would like to order it if needed....
If the evap can got full of gas it will eventually leak out / evaporate I would imagine and fix itself? Never try to squeeze extra gas into the car - stop filling when it pops the first time.
Mine used to make that smell and it was the crossover o-rings. Sloshing fuel should not be filling up your evap.
Last edited by Apocolipse; 11-29-2020 at 04:32 PM.
Pretty sure once the charcoal gets wet it's done from ever working again. I bought the car used and I never fill past the first shutoff. Question is did the fill level vent valve break and how can you tell?
I mean, unless I'm totally wrong? A tank pressure sensor tells the computer to tell a solenoid to open to vent pressure to the canister or to the engine if possible to be burned...
Last edited by rockinSeat; 11-29-2020 at 05:27 PM.
Reason: Comment
Well, not totally wrong, but not totally right either.
Here's how the Evap system works as described in the shop manual, hope this helps explain it:
Evaporative Emission Control System Description
EVAP System Operation
The evaporative emission (EVAP) control system limits fuel vapors from escaping into the atmosphere. Fuel tank vapors are allowed to move from the fuel tank, due to pressure in the tank, through the vapor pipe, into the EVAP canister. Carbon in the canister absorbs and stores the fuel vapors. Excess pressure is vented through the vent line and EVAP vent solenoid valve to the atmosphere. The EVAP canister stores the fuel vapors until the engine is able to use them. At an appropriate time, the control module will command the EVAP purge solenoid valve ON, allowing engine vacuum to be applied to the EVAP canister. With the EVAP vent solenoid valve OFF, fresh air is drawn through the vent solenoid valve and the vent line to the EVAP canister. Fresh air is drawn through the canister, pulling fuel vapors from the carbon. The air/fuel vapor mixture continues through the EVAP purge pipe and EVAP purge solenoid valve into the intake manifold to be consumed during normal combustion. The control module uses several tests to determine if the EVAP system is leaking.
Nowhere does the manual mention anything breaking if the gas tank is overfilled, or the charcoal in the cannister being harmed by exposure to gasoline.
Thanks wjnjr, that description helps but I am still a bit confused.
"Fuel tank vapors are allowed to move from the fuel tank, due to pressure in the tank, through the vapor pipe, into the EVAP canister. "
So if you overfill your gas tank, does gas go up the vapor pipe and flood the canister? Isn't there some sort of valve? The gas tank has to fill before the gas pump shuts off. I don't understand the valve mechanism involved.
That description didn't say much about relieving pressure when the car is off or engine cannot burn fumes. I thought the charcoal cleaned the air a bit before releasing fumes to the atmosphere????
Dealer told me they have replaced plenty of canisters on different cars and once wet they are ruined. I'm sure I need a new canister, but wondering if there is anything else that's broken that caused my canister to flood.
maybe caught a fuel pump that had a really high flow rate... or too quick on a left hander on a full tank.... it's not tough to replace... passenger side of the trans, I believe there's an access door in the frame specifically to service this... right above the brake duct behind the wheel liner...
Hi DrewZ06, I have read 'canister access door's a couple of times, but everything says the passenger tank must be dropped. It would sure be nice if not. If that is the case, I will try replacing just the canister first. Something tells me it is too good to be true....
Hi DrewZ06, I have read 'canister access door's a couple of times, but everything says the passenger tank must be dropped. It would sure be nice if not. If that is the case, I will try replacing just the canister first. Something tells me it is too good to be true....
I can't find my photo but if I remember correctly you're going to want to disconnect the passenger exhaust and move it out of the way... I seem to recall that hatch is for access to the tank and lines....
@drewz06 , if no leaks and no codes, but fuel vapor smell when hot, can you think of anything else to replace besides canister? You mentioned high flowing gas pump, do other parts besides canister break when this happens?
@drewz06 , if no leaks and no codes, but fuel vapor smell when hot, can you think of anything else to replace besides canister? You mentioned high flowing gas pump, do other parts besides canister break when this happens?
Sorry I know I'm repeating myself.
when the cars hot, slowly open the gas cap to see if you've got excessive pressure buildup... I don't have the manuals in front of me but I remember seeing some good stuff when I was doing my pump swap... will check for ya
When I took the car in hot to the dealer,. They put it on a lift and hooked it up to a smoke machine and a computer. They built up decent psi in the tank and demonstrated no leaks. I believe they commanded the vent valve by the transmission to open and smoke came out, along with strong vapor. The tech said if the canister were working, the fuel smell would be less. So then they said like $2000 for a new canister install and they would see what else they find on the passenger side tank. I thought it was a bit steep and wanted a project to work on anyway. Fwiw, I have seen a couple drops of fuel inside the gas cap...isn't there another hose that connects to the filler neck?
All I can tell you is replacing the crossover o-rings worked for me in the EXACT same situation as you are in. No codes no visible leaks but fuel smell pass side after corner carving.
Appreciate that info Apocalypse. I will look out for that. I was going to have a look behind the rear wheel molding tonight but by chance I parked too close to the pillar in my garage and couldn't get the wheel off. Live and learn. In other news, I found the canister in Amazon for $99. Most others want $136 or 150.
Fuel System Description (W/LS3 or LS7)
Fuel Tank
The fuel storage tank is made of high density polyethylene. The fuel storage tank is held in place by 2 metal straps that are attached to the under body of the vehicle. The tank shape includes a sump in order to maintain a constant supply of fuel around the fuel pump strainer during low fuel conditions or during aggressive maneuvers.
The fuel tank also contains a fuel vapor vent valve with a roll-over protection. The vent valve also features a 2-phase vent calibration which increases the fuel vapor flow to the canister when the operating temperatures increase the tank pressure beyond an established threshold.
On-Board Refueling Vapor Recovery (ORVR) System
The on-board refueling vapor recovery (ORVR) system is an on-board vehicle system to recover fuel vapors during the vehicle refueling operation. The flow of liquid fuel down to the fuel tank filler neck provides a liquid seal. The purpose of ORVR is to prevent refueling vapor from exiting the fuel tank filler neck. The ORVR components are listed below, with a brief description of their operation:
• The fuel tank--The fuel tank contains the modular fuel sender, the fuel limiter vent valve (FLVV), and 1 rollover valve.
• The fuel filler pipe--The fuel filler pipe carries fuel from the fuel nozzle to the fuel tank.
• The evaporative emission (EVAP) canister--The EVAP canister receives refueling vapor from the fuel system, stores the vapor, and releases the vapor to the engine upon demand.
• The vapor lines--The vapor lines transport fuel vapor from the tank assembly to the EVAP canister and engine.
• The check valve--The check valve limits fuel spit-back from the fuel tank during the refueling operation by allowing fuel flow only into the fuel tank. The check valve is located at the bottom of the fuel filler pipe.
• The modular fuel sender assembly--The modular fuel sender assembly pumps fuel to the engine from the fuel tank.
• The fuel tank pressure (FTP) sensor is located on top of the fuel tank vapor dome.
• The FLVV--The FLVV acts as a shut-off valve. The FLVV is located in the fuel tank. This valve has the following functions:
- Controlling the fuel tank fill level by closing the primary vent from the fuel tank
- Preventing fuel from exiting the fuel tank via the vapor line to the canister
- Providing fuel spillage protection in the event of a vehicle rollover by closing the vapor path from the tank to the engine
• The pressure vacuum relief valve--The pressure vacuum relief valve provides venting of excessive fuel tank pressure and vacuum. The valve is located in the fuel fill cap.
• The vapor recirculation line--The vapor recirculation line is used to transport vapor from the fuel tank to the top of the fill pipe during refueling to reduce vapor loading to the enhanced EVAP canister.
11-27-2020, 02:02 PM
Fuel Smell Evap Canister Parts to Replace
