don't think it's the bov.. but who know's so far this summer with 2 track days under my belt so far so good.. no fuel smell yet. i should note that it hasn't been hot either. nothing above 20C last year it only happend at 30+c and when driving hard.

I've told my mechanic friend about this. and he said he'll try to help diagnose the problem if it comes up again. he's got some sort of air sensor device that can track down hydrocarbons. he figures it's comming through the AC unit during high temps and high fuel pressure as in wot driving. so yeah next time it happens he wants to use his tool to attempt to find the problem.

 

That there seems to be a correlation with the CBV opening doesn't say a lot. Many things happen when you lift. For example, that's when the EVAP system might do a purge. So this all fits the EVAP theory just as much as a new theory.

 

I'm just sharing my experience just in case someone could find it helpful, coz this thing annoys me. Coz u guys r right, the smell is inside the cabin, no doubt. When it was 110deg here, it was so foul inside the cabin I was getting dizzy.

I'm just hoping that someone could actually find the problem and let us know of the fix. I've done almost everything, close to tearing the car apart, to get this straight but to no avail.

Bowrepublik, I'm not saying I want it to happen to u again, but when it does, please please please diagnose it with ur friend with the sniffer.

 

Yea when I drive it hard, no matter what temp(this happened to me in the winter) my car smells like pure e85

 

My tuner (chetrickerman) and I figured out what was causing the fuel smell in my car today. It was 101 degrees in Denver and we figured it would be a great time to retune and make sure I wasn't getting any knock under the highest temperatures we would see in this area. After several runs we started getting the fuel smell (badly) and the logs started showing lean fuel conditions (over a full point off, was in the 12's) and the fuel trims were all over the place, anywhere from 7% to 12% corrections. We popped the hood and checked the injectors... the fuel was so hot it was vaporizing, causing lean fuel conditions.

Don't know if there's anything you can really do about it, but I would definitely stay out of full boost when it happens. Hope this helps.

 

The raw gas smell is in the cabin, not on the engine

 

The cabin is just where it smells the strongest. It about made me sick.

 

DSMs had the problem of not restarting when hot because heat from the head would soak into the intake manifold and, from there, to the fuel rail. The easy trick to get a DSM to restart when hot was to spray down (or put a bag of ice on) the fuel rail. What I did was to add a phenolic spacer between the head and intake. Not only did this solve the hot-start problem, but in combination with water/meth injection, my intake manifold was cool to the touch - even cooler than ambient - at the end of an autocross run. (Full disclosure: I also had a blocked-off EGR.)

My guess is that this is indirectly related to the problem of a gas-vapor smell in the cabin. My guess is that fuel running round and round between a hot fuel rail and the tank is heating up all of the fuel and raising the pressure in the tank. This is overwhelming the EVAP system which then leaks fumes into the trunk. (Note that Evo Xs have the EVAP in the left-rear corner and, from there, it can get into the trunk and, therefore, into the cabin.) This fits the observation that the smell is often worse with the AC on. With the cabin air recirculating, the normal flow of air in the cabin from front to back is changed to a loop going back near the interior roof and returning to the front near the floor. This will pull air from the trunk.

In short, while the observation that hot fuel is correlated with the smell is very useful, it doesn't move me, personally, away from the EVAP theory. Please, next time that you smell gas, open the trunk and sniff the left side.

 

No smell in the trunk at all. No smell in the engine bay at all. 100% of the gas smell is inside the cabin.

 

Hm. That's a stumper, then. Have you checked the hard-lines under the floor? One or two of them is EVAP.

Or do you simply have a small container of race-gas behind the passenger seat?

 

Yup, no smell in the trunk. Just cabin. Recirculating the air actually gets rid of the smell.

 

Ah. Then we should be looking near the cabin-air intake (where-ever that is).

 

ouch for raw bad gas smell

 

I'm not saying that vapor is escaping at the injectors, that's not the case. I'm just saying that we know fuel was vaporizing based on the lean conditions. I have no idea where the fuel vapor was actually escaping, save for the very strong odor in the cabin.

 

That's the part that is weird. When you heat up the fuel, the increase in pressure is relieved via the EVAP system, which waits until the next time that certain conditions are met (which includes being off-boost) before venting the vapor into the intake manifold. Yes, the line between the EVAP can and the intake runs under the car, but I really don't see how that will end up inside the cabin if the hard-line is broken; it's not like the cabin-air intake is under the car.

My only new idea is that the EVAP flex hose from the hard-line to the intake is broken and it's broken somewhere near the cabin-air intake, which is at the base of the windshield. I would try tracing this hose to check. Alternatively, disconnect the EVAP purge line at the left rear of the car and see if it holds pressure. When the car is off, the EVAP purge valve will be closed, so it should hold pressure.