Olitho

The last couple of races my car has been putting out a raw fuel smell when I start driving the car. I put in a race load of fuel that is usually around 6/10-8/10 of a full tank. It is a 2002 Z06 T1 car, so it is mostly stock..

As soon as I start driving the car I can smell the fuel. When the fuel load burns down to 1/2 tank or less it seems to go away or perhaps I am not noticing it as I am racing and grow accustomed to the smell, but I think it goes away.

Of course this is a disconcerting problem. Pulling the fuel tanks I can't see any evidence of a fuel leak. The hoses seem to be OK. The hose fittings on the tank seem OK.

I could be wrong, but a couple of times I have put it in the trailer thinking I would have enough fuel for practice when I go back to the track, but 2-4 weeks later when I roll her out she is empty or near empty. I did not record my actual fuel load so I this is not absolute data.

I have a race coming up in August.

Has anyone eles experienced this?

Do you have any ideas/recommendations?


Thanks,

Oli

ghoffman

Sure, just conceed the race to Roy! Seriously, some shops will have a sniffer that can ioslate the leak, if you can smell it it needs to be found.

davidfarmer

is it around the tanks, or engine bay area????

It is VERY easy to damage the nipples on the tops of the tanks....the crossover "vents" well call them (above the crossover fill hoses). I've damaged them welding, even drilled a hole in the tops of my tanks once while mounting some hardware in the back.

However, it sounds like you've actually pulled the tanks?????

Is the EVAC system intact...I think the canister is in the rear passenger fender. Could it be missing/damaged etc???? Those EVAC lines also go all the way to the intake manifold, basically a plastic vacuum hose, and can be easily damaged during engine swap etc.

Maybe you should keep a Pilot flame burning just in case

Olitho

Thanks David for your suggestions.

I am not sure where the smell is coming from. I just assumed it is coming from the back tank area since it only seems to happen with bigger fuel loads.

We have pulled the tanks and nothing is evident upon a cursory look. I am going out right now to try the pilot flame. I will get back to you in a little while on how that works....


Oli

GettReal

I also noticed this recently. I had mine up on the hoist a couple days ago at my race shop replacing an O2 sensor and my mechanic told me its most likely a part (the name escapes me right now) something like a fuel check valve or something like that which is stuck open. Its located on the passenger side near the diff (general area) I will get the "real" part name tomorrow for you. He also told me that I will notice the fumes smell more on a full tank so thats why it rings a bell with what you said.

Olitho

Thanks, I am very keen to find out what your mechanic has to say.


Oli

GettReal

I just sent him a text to see if he's still awake... if not..look for my post in the morning

I think it might be close to what David mentioned about the EVAP system

Olitho

The pilot flame seemed to work. I found something, but I will have to let you know after the fire department lets me back into the garage....

TedDBere

Reminds me of all those Darwin stories of mechanics trying to weld things to a gas tank...

GettReal

ok, check your codes as well and see if you have a P0440. The next time I am at my shop, we will be running a diagnostic but he's pretty sure for me we need to replace the EVAP purge valve. Same symptoms as you. Wish I could get my car up so I can take a pic of it for you. Heres some tech info on this.

P0440 OBD-II Trouble Code
Technical DescriptionEvaporative Emission Control System Malfunction

What does that mean?This indicates that a part of the EVAP control system is no longer fuctioning correctly. The EVAP system consists of many parts, including (but not limited to) the gas cap, fuel lines, carbon canister, purge valve, and other hoses. The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine.

CausesA code P0440 could mean one or more of the following has happened:

The gas cap is not installed or working properly
The purge solenoid has failed
The canister is plugged and not working properly

Possible Solutions

Inspect the EVAP system for cuts/holes in tubes/hoses
Inspect for damaged or disconnected hoses around the Evap purge solenoid
Check and/or replace the sensor
Check and/or replace the purge valve
Have a professional use a smoke machine to detect leaks

Allthrottleandsomebottle

Very well could be the OEM fuel filter nipples.........been there.

Olitho

Very good stuff you guys. We will take a look at that today.

Oli

racerwannabe

my car had a pin hole in the tank on the top under where the roll bar was welded in...
then the evap system had a leak...
new tanks fixed mine..
then again you were smarter than me to remove the tanks while the weding was going on....
Johnny

DALE C

Is the car hard to start (long crank) after it sits? If it is I would be looking at the lines usually the fuel filter as mentioned above. If it does not have a long crank I would look at the tanks.

fatbillybob

My guess is solonoid vent or purge valves. Look of DTC on these first. Smell going away could be the time it takes to bleed the fuel out of the charchol canister which should be a sealed system if the system is working right and or cracked lines in the evap system. Solonoid vent valve is normally closed except during testing by the OBD2 system. It could be open and you get the smell the solonoid purge valve allows the fuel to get sucked into the intake and is computer controled to control mixture.

Olitho

You guys are great!

Yes, it turned out to be the solenoid. We fixed it last night and I went out to AutoClub Speedway, aka California Speedway, today and filled up twice and no fuel smell.

Problem solved.


Thanks,

Oli


PS. Now if Steve Schmidt can only figure out why his T1 car is overheating. Last race and today's track day his car is over-heating. Today we took some street Corvette drivers out at lunch for three parade laps and even that caused his car to overheat. He has check for air in the system, drained it and and filled with distilled water and Water Wetter and it still overheats. He has the authorized Ron Davis radiator I and all the other T1 guys are running locally.

fatbillybob

Easy things are to remove T-stat to see if that changes result. second reverse flush the radiator or better yet take it out and boil it out. third sometimes pump can loose efficiency with age as the clearance of the impeller to pump body grows. Pressure test system will find leaks and air intake sources that can encourage pump cavitation and radiator hot spots due to poor flow

GettReal

Glad you got it fixed

ErnieN85

check for exhaust gas in the radiator.most good shops have atester for this.
it's a sign of ablown head gasket or cracked head!

Z11409

Check FAN switch,from the engine side blow out both radiator and AC condenser.One or two OFF'seem to plug up radiator core with fine gritty Mojave rock and sand.