whenever i get out of my car after driving sometimes, you can smell a faint hint of fuel comming from somewhere. when i bought my car, the vapor canister was gone with the lines that ran into it just plugged. is this what is causing the fuel smell? can this hurt anything at all or is it ok to run like this? also, someone told me today that 3rd gens needed a pressure/vacuum release vented fuel cap, is this true? because everytime i go to fill up it seems like air rushes out when i take off the cap.

 

Well, my gas tank does the same thing. But the canistor is supposed to hold vapors and stuff, so it could possibly be the problem. Get one from a junk yard, like $4 or so.

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88' GTA 350 MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass

 

My nic name on the corvette forum is Bill's86Coupe..click on here to see a thread I just started on the gas smeel and pressure in the tank and etc.

http://www.corvetteforum.cc/ubb/Foru...ML/010503.html

I will also post a reply to an email I got from a guy name David..hes a Corvette guru and TPI expert..he wrote for Corvette magazines back in the 80's on tech how tos and etc.
I told David what was wrong and what I found out...and he explained alot to me in the email.




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1986 Vette Coupe,auto, 357 L98 w/alum. heads,40 over,crane cam,3.73 Gears,The usual Mods..
Had an 86 Bird before..want to get another F car again!

 

Heres a copy of his email to me after I wrote to him.

David writes:

Bill,
I never mind answering your questions, my computer at home is so slow and I've been busy at work I just don't have the time to spend on the forum, I do get on from time to time but I will try my best to answer any e-mail I get, probably the best way to get in touch with me.

You are correct if the vent line is clogged to the canister you can build up to much pressure in the tank in hot weather. There is a check valve in the gas cap that lets air in to keep the tank from imploading and also to release vapor if the pressure gets to high. In cool weather pulling gas out of the tank will create low pressure in the tank(if the valve sticks the tank can impload and I've seen it happen).

In hot weather the fuel heats up and pressure goes up and should get trapped in the cansiter and pulled out of the canister when driving.

If the line to the canister gets clogged it can't vent and pressure goes up until it gets to a point were the cap valve opens and vents. If the vent line from the tank to the canister is blocked you will get a gas smell out the cap and pressure out the cap when you open it.

Blocked cansiter purge valve will probably give you a gas smell or gas at the canister. An opened cansiter purge valve will probably give you a poor running condition maybe rough idle or code
45. Just somethings to think about.

I don't think there is any problem with going with rubber hoses instead of steel lines. You will get a lot of heat in the fuel tank especialy when it's so hot out side, remember the fuel goes up to the fuel rails on top of the engine and then returns back to the tank. I'm sure there is a lot of heat picked up by the fuel running through the fuel rail, that's one of the reasons for running the fuel pressure they do to help prevent vapor lock.

The 85 used to run between 28 and 32psi at idle which was a real problem in hot weather especialy when injectors started to get a little dirty, so one of the things they did in 86 to help with hot drivibility was increase operating fuel pressure.


But it sounds like you're on the right track, let me know how you make out.

David

Me:
I hope this helps some of you or at least gets ya started on the right track...I have to replace a 9 foot steel line since air wont pass through it and it caused the vapors in the tank to build tremendous and get hot...very dangerous.

Also if you smell gas, see if its under the hood or where the cannister should be..maybe a line broke.
I replaced all mine(rubber hoses around the cannister and etc) to be on the sure side since most of it was so old.

I just found out how important it is to have the vapor recovery system working right...dont even think of Junk yard parts...mine was falling apart and the junk parts may do the same..the new parts arent that much money.
A gas smell can lead to problems lke a fire or something nuts.
My gas tank was so hot I couldnt touch it for more then a second.

So now im on the road to repair it and will post here as well what I find so maybe it helps others.

 

When I had removed my cannister, I had also plugged mine line and had the same problems. I would even have gas overflow and spill down my quarter panel when there was too much pressure.

You need to unplug the line, maybe run a vaccuum hose to below the car.

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1989 IROC-Z 5.7L
NOS 150HP kit
ProBuilt 700R4, PI Vigilante 2800 stall lockup
Baer Brakes 12" Sport System