73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Fuel Systems and Drivability => Topic started by: 1979SIERRAGRANDE on October 19, 2016, 08:24:06 pm
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:-[ Good evening everyone
Ive had a difficult summer this year driving my 1979 Gmc c1500 in the heat , mostly because its like 20 degrees hotter in the cab than outside hot air seems to be coming from underneath the dash not from vents most of the time smells like gas I've checked for fuel leaks replaced all rubber hoses this summer as well as the fuel pump. Ive as well inspected the firewall from the engine bay there is some rust but no holes i can see through. I suspect the firewall needing insulation any help or opinions is greatly appreciated also first time posting!
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well your fan may on all the time on a low setting and the blender door for the heat or vent might be stuck or cracked open causing you pull heat from the heater core. one option is unplugging the blower motor or install another switch for the main wire on the blower motor
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i unplug my fan for summer runnin. ......are you sure your smelling raw gas, or is it exhaust fumes?
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its raw gas i redid the exhaust from the header back
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I was out working on my truck the other day freshening up the wiring putting wire loom on it as well i redid the ground for the blower motor because it was frayed so i replaced the wire. Turned on the truck to test it and go over to the motor to see if its running just to find out its leaking air out of the heater lines as well as the ac lines going into the ac box . Anyone know or have an idea to replace the cork like OEM adhesive to insulate the ac lines as well as keeping engine fumes out ?I'm thinking this has something to do with the fumes I've been smelling lately.
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Hopes this helps to see my problem
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ac
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heater
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To reseal the evaporator housing use flexible A/C Insulation Tape (https://www.napaonline.com/napa/en/p/TEM209491/TEM209491). Any vendor that sells 4 Seasons (http://ecatalog.smpcorp.com/FS/#/vehicles/parts/num/59010?type=s) HVAC products should be able to get it. Raw fuel odor can be an indication of a fuel hose or line leak, a fuel tank or sender leak, a saturated vapor canister, a bad fuel pump, a leaking fuel cap, etc. You need to identify the source and get it corrected to avert the potential for fire.
Cooling system heat will melt the A/C tape, so to reseal the heater pipes substitute closed cell foam.
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To reseal the evaporator housing use flexible A/C Insulation Tape (https://www.napaonline.com/napa/en/p/TEM209491/TEM209491). Any vendor that sells 4 Seasons (http://ecatalog.smpcorp.com/FS/#/vehicles/parts/num/59010?type=s) HVAC products should be able to get it. Raw fuel odor can be an indication of a fuel hose or line leak, a fuel tank or sender leak, a saturated vapor canister, a bad fuel pump, a leaking fuel cap, etc. You need to identify the source and get it corrected to avert the potential for fire.
Cooling system heat will melt the A/C tape, so to reseal the heater pipes substitute closed cell foam.
I've had the problem since i first bought the truck . Since then I've replaced the fuel pump fuel hoses fuel filter as well as both fuel caps and vapor canister filters and really only gets bad when it gets hot on a hot day.
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Might be a tank venting problem. Are the fuel tank caps sealed or vented? With a carbon canister, they should be sealed. Have you ever checked the fuel sender o-ring?
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Might be a tank venting problem. Are the fuel tank caps sealed or vented? With a carbon canister, they should be sealed. Have you ever checked the fuel sender o-ring?
No i have not if i drive the truck sometimes i used to see the canisters blow out carbon pebbles and cover the fender thats why i decided to change the filters
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The carbon canister is probably original to the truck and likely saturated. Since it's spitting carbon granules it should be replaced, otherwise some of the granules may find their way into the carburetor fuel bowl through the vent line and cause flooding or other fuel delivery problems.
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The carbon canister is probably original to the truck and likely saturated. Since it's spitting carbon granules it should be replaced, otherwise some of the granules may find their way into the carburetor fuel bowl through the vent line and cause flooding or other fuel delivery problems.
Can you even find replacement ones these days ? Every squarebody I've come across they either bypass them or throw them out completely
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Occasionally, they come available. Post the number cast into the top of the canister.
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You can get the basic three hose vapor can and the five hose can.
Three hose is Standard CP1022
Five hose is Standard CP1004
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You can get the basic three hose vapor can and the five hose can.
Three hose is Standard CP1022
Five hose is Standard CP1004
Occasionally, they come available. Post the number cast into the top of the canister.
The ones i have in the truck right now is one 5 inlet and 3 inlet thats close to 350 dollars shipped any way i can just remove the canisters and run a breather to the vent hoses for the fuel tank ?
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Where are you pricing that... your GM dealer? No way the evap can costs $350.
If it stinks of raw fuel now it'll be worse without the can.
Brand New AC Delco 215-151 five hose evap can is $103 on Amazon with Prime shipping. https://www.amazon.com/dp/B000C9K1DK (https://www.amazon.com/dp/B000C9K1DK)
The five hose Standard CP1004 evap can costs $135 on Amazon.
If you don't have to pass emissions just get the $55 three hose can...
Three hoses to hookup.
1 - Purge Tee into the PCV valve hose.
2 - Purge vacuum signal from ported vacuum.
3 - Vapor from the tank.
Cap the other two vacuum lines and leave it.
If you google the standard motor products or delco part number you'll probably find better prices. I was being lazy by just checking Amazon.
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Where are you pricing that... your GM dealer? No way the evap can costs $350.
If it stinks of raw fuel now it'll be worse without the can.
Brand New AC Delco 215-151 five hose evap can is $103 on Amazon with Prime shipping. https://www.amazon.com/dp/B000C9K1DK (https://www.amazon.com/dp/B000C9K1DK)
The five hose Standard CP1004 evap can costs $135 on Amazon.
If you don't have to pass emissions just get the $55 three hose can...
Three hoses to hookup.
1 - Purge Tee into the PCV valve hose.
2 - Purge vacuum signal from ported vacuum.
3 - Vapor from the tank.
Cap the other two vacuum lines and leave it.
If you google the standard motor products or delco part number you'll probably find better prices. I was being lazy by just checking Amazon.
i checked amazon i have two evap cans i guess one for each tank
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Thanks again guys for the quick responses i have been getting this forum rocks ! 8) 8) :)
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used to see the canisters blow out carbon pebbles and cover the fender thats why i decided to change the filters
wouldnt that suggest that you are getting pressure from some source blowing into the canister? like a fuel line from the selector valve connected to the wrong place filling the canister with fuel
My canister has a vacuum line and a vent line , but nothing that would cause fuel to fill the canister or pressurize it
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used to see the canisters blow out carbon pebbles and cover the fender thats why i decided to change the filters
wouldnt that suggest that you are getting pressure from some source blowing into the canister? like a fuel line from the selector valve connected to the wrong place filling the canister with fuel
My canister has a vacuum line and a vent line , but nothing that would cause fuel to fill the canister or pressurize it
The "filter" is a fresh air inlet filter to prevent dust from being drawn into the canister by engine vacuum. The activated carbon granules contained inside the canister passively absorb fuel vapors that evaporate from the fuel tank(s) and the carburetor fuel bowl and then gradually migrate into the EVAP canister through a physical process of partial pressure equilibrium. While the engine is running, fresh air drawn through the canister filter and across the carbon granules only partially purges the fuel vapor that collects in the canister. A trace amount of fuel vapor remains permanently bound to the carbon granules. Eventually, the carbon granules saturate with fuel and the canister loses its effectiveness. This is normal over the useful life of the canister.
Rarely, a canister purge valve diaphragm perforates, exposing the tank and carburetor vent lines directly to engine vacuum. In such cases raw fuel can be drawn into the canister resulting in immediate saturation with fuel dripping from the canister. In this situation the canister is rendered instantly useless.
In either scenario, the heat necessary to totally drive fuel from carbon granules and restore the effectiveness of a canister would destroy the canister - not-to-mention the extreme hazard of heating the fuel in the first place. The only solutions are canister replacement or elimination. The consequence of elimination is noxious fuel odor, especially on warm days.
Carbon granules leaking from an EVAP canister can be a problem caused by failed internal baffles/screens or liquid fuel floating the carbon granules out through the vent lines.