Strong Fumes
Thread Starter
Instructor
Joined: May 2018
Posts: 248
Likes: 11
Strong Fumes
I have a 1977 L82 4 speed 370 rear gear. A/C detete. Bought this car 18 months ago 70 K miles on the odometer running a non original Q Jet which I replaced with an AVS 2 edelbrock. Replaced the cast iron manifolids and installed another set from Summit 2 1/2 outlets cost less tha $200.( didn't want to chase leaks), trailered it to a local muffler shop and had 2 1/2 inch pipes going into Magniflows. I could not beleive the increase in power, great investment. Before all of these changes the car was very hard to start and had a strong exhaust odor. This car still has a gaseous odor. Very recently after a 150 mile run crusing 70-80 MPH it still has an unpleasanr odor. My PVC line goes into the carb. the other has a K&N breather. I do have a minor rear main oil leak. I pulled the plugs and they are all burning clean. Compression checks all within 120-135. When I bought the car it did have a heavy coating of oil and grease on the engine block and pan which I have have cleaned 75%. The performer intake has been off and resealed as well as the valve covers.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,809
From: Cool Northern Michigan
Just a couple thoughts here:
PCV goes into the carb. Which port? One port might be "timed" vacuum.
120-135 compression seems a bit low to me. Rings might be on their last leg.
With that compression, I suspect some blow-by issues.
Charcoal Canister in drivers side fender well is likely shot. Most owners just ignore it but it can give -off gas smells.
PCV goes into the carb. Which port? One port might be "timed" vacuum.
120-135 compression seems a bit low to me. Rings might be on their last leg.
With that compression, I suspect some blow-by issues.
Charcoal Canister in drivers side fender well is likely shot. Most owners just ignore it but it can give -off gas smells.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
Does it have a strong fuel odor when it is running, or when it is stored? If when running, the carb is probably running too rich and the exhaust has significant amount of unburned fuel. If odor when sitting in garage or storage, you have a minor fuel leak (oozing, not dripping) or a defective {or removed} fuel vapor recovery system.
Last edited by 7T1vette; Jan 13, 2020 at 07:54 PM.
Melting Slicks
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From: Chapel Hill NC
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I recently removed my defective charcoal canister in my 71. I plugged the lines and installed a vented gas cap.
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Thread Starter
Instructor
Joined: May 2018
Posts: 248
Likes: 11
This has to do with the vapor return line on my '77 L82. I have had strong gaseous odors since I bought this car 18 months ago. I pluggrd the return line hoping it might help but nothing has changed. Installed new Edelbrock carb, new exhaust 2 /1.2 pipes cat delete with MF's. This car has always had a rough idle but the car runs strong though all the gears (4 Speed) 370 gear. the last time a went out for a 150 mile cruise I came back with a head ache so I have to get this issue solved. I will break out the vacuum gauge and play with the carb and see if I may be running too rich; however, my plugs are new and look clean except for #1 and #2 they have a darker appearance but not oily. The car shows 71K miles, and the previous owner had no clue about auto mechanics so I don't know any history on this car.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
Your fuel tank/system MUST have a vent somewhere to equalize pressure in the tank. The charcoal vapor canister is the vent with operating systems. If you remove the canister and plug the line you do not have a vent. Either put the vapor collection system back in the car or put a 'vented' gas cap on the tank.
Thread Starter
Instructor
Joined: May 2018
Posts: 248
Likes: 11
Ok let's drop back and punt. the charcoal canister is still in place the outgoing hose coming from the canister is plugged. When I bought the car it was open and pushed below the brake booster. I pluged it thinking it might help the odor. If my '77 gas cap is not a vented cap then I have a un vented system, if the gas cap is vented then I should be ok other than still having gaseous odors. That means I will have to go back and check the settings on my Edelbrock AVS-2 CARB. I don't have an exhaust leak because I have replaced everthing from the heads to the tail pipes.