Fuel System Problem - The 1947 - Present Chevrolet & GMC Truck Message Board Network

soule64 · 09-21-2010, 11:56 AM

Looks like I goofed something up with the fuel system and I hope someone might help.

What I have - 87 model 16 gallon tank and sender with an ep381 pump. Steel braided hose to the corvette regulator and return to sender. More steel braided hose to the engine fuel rail. Used another hose from the vent port (next to the main filler port) on the top of the tank and ran it to the charcoal canister for tank ventilation. Filler neck and cap from an 85 connected to the tank fill port with a standard filler hose. Small port (vent?) on the sender is capped as well as the 5/8' port on the filler neck. I figured the large line to the canister would provide enough ventilation.

What happened - Driving home last night a lane opened up in front of me and I hammered it. Ran the engine up to around 5k and out of nowhere, the cab was filled with gas fumes - I mean it was overpowering. I limped home about a mile away and popped the hood. the right side of the engine bay was soaked with fuel. How it didn't catch fire I'll never know because it was everywhere. I pulled the canister and it was so full of fuel that I couldn't push any air through it. The line from the canister back to the pump was full of fuel.

So, I am trying to picture this in my head how so much fuel (or any for that matter) got to the canister. Shouldn't that line actually pull a small amount of vacuum as fuel is pushed to the engine? Since all of the other ports are sealed, how did the engine keep running without tank ventilation? The pump should have cavitated under the Vacuum, but instead the fuel is pushed out of the ventilation hose/canister? Why did this happen under engine load/high rpm and not all of the time (been driving it for 2 weeks) - with the throttle wide open you are burning more gas thus relieving line pressure, right? The in-tank is constant pressure and wouldn't be affected by engine load - it works at 100% as long as it gets 12vdc.

I am not sure what I did wrong with this thing. Any help or suggestions would be greatly appreciated.

09-21-2010, 11:56 AM	#1
soule64 Registered User Join Date: Feb 2008 Location: Huntsville, AL Posts: 197	Fuel System Problem Looks like I goofed something up with the fuel system and I hope someone might help. What I have - 87 model 16 gallon tank and sender with an ep381 pump. Steel braided hose to the corvette regulator and return to sender. More steel braided hose to the engine fuel rail. Used another hose from the vent port (next to the main filler port) on the top of the tank and ran it to the charcoal canister for tank ventilation. Filler neck and cap from an 85 connected to the tank fill port with a standard filler hose. Small port (vent?) on the sender is capped as well as the 5/8' port on the filler neck. I figured the large line to the canister would provide enough ventilation. What happened - Driving home last night a lane opened up in front of me and I hammered it. Ran the engine up to around 5k and out of nowhere, the cab was filled with gas fumes - I mean it was overpowering. I limped home about a mile away and popped the hood. the right side of the engine bay was soaked with fuel. How it didn't catch fire I'll never know because it was everywhere. I pulled the canister and it was so full of fuel that I couldn't push any air through it. The line from the canister back to the pump was full of fuel. So, I am trying to picture this in my head how so much fuel (or any for that matter) got to the canister. Shouldn't that line actually pull a small amount of vacuum as fuel is pushed to the engine? Since all of the other ports are sealed, how did the engine keep running without tank ventilation? The pump should have cavitated under the Vacuum, but instead the fuel is pushed out of the ventilation hose/canister? Why did this happen under engine load/high rpm and not all of the time (been driving it for 2 weeks) - with the throttle wide open you are burning more gas thus relieving line pressure, right? The in-tank is constant pressure and wouldn't be affected by engine load - it works at 100% as long as it gets 12vdc. I am not sure what I did wrong with this thing. Any help or suggestions would be greatly appreciated.



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.