Fuel vapor separator with fuel injection

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I have a 383 stroker with a Holley sniper EFI. On one of our Seattle hot days it was around 95 and I was driving on the freeway. MAT/F went up to 160 to 165 degrees. I think that I vapor locked, but not sure.

AFR dropped to 30 to 40 before dying. Confirmed fuel psi was around 20 when it would not start. Unfortunately, I did not check the gas cap for fuel tank pressure. I have a rail mounted fuel pump, mounted next to the transfer case on the rail.

I sprayed the fuel lines down with a water bottle and it started right up.

Talking to one mechanic, he said get rid of the vapor separator and just T the vent into the filler neck.

My cab smells a little like gas and I’ve confirmed the vent line is not routed outside the rig, which explains the slight fuel smell.

Thoughts? Keep the vapor separator or T the vent into the filler neck? Still need to verify my gas cap is vented.
 

GA Architect

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FWIW: Because of this...
1660442242260.png


I couldn't find a good separator/evaporator in time, so I installed one of these...
1660442281394.png


1660442373424.png


And that is how I'm going to roll, till my 40 tells me otherwise.
 
Joined
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KY
Maybe it is just me but I don't see a connection between the vapor separator and the vehicle vapor locking other than the word "vapor". The separator has nothing to do with the temperature of the fuel in the fuel lines. If your fuel lines are too close to a heat source than it is probably time to put an insulator on your fuel line.
 

Silver City Cruiser

Bills Toy Shop
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Farmington,Nm
I agree with Byron. You now have less room for expansion in the vapor system. Fuel may just flow through that pitchfork tee if the tank is full and it's hot with expansion. The expansion tank allows for a full tank to expand without contaminating the canister.Do you still have a charcoal canister? That is where the tank vents normally , filtered with the charcoal and vented overboard in the frame rail, cleaned up. Without it you will just vent overboard and will get some fumes and perhaps fuel out the vent. If you still have it it may get fuel in it now and saturate it. Make sure the vent is not near the exhaust or you could have a fire if it overflows...be safe.
 
Joined
Jul 18, 2018
Messages
129
Location
Seattle
Sorry, haven’t been watching the thread, little brush with Covid.
FWIW: Because of this...
View attachment 3086192

I couldn't find a good separator/evaporator in time, so I installed one of these...
View attachment 3086193

View attachment 3086199

And that is how I'm going to roll, till my 40 tells me otherwise.

I’m curious @GA Architect if you have EFI or carb?

I agree with Byron. You now have less room for expansion in the vapor system. Fuel may just flow through that pitchfork tee if the tank is full and it's hot with expansion. The expansion tank allows for a full tank to expand without contaminating the canister.Do you still have a charcoal canister? That is where the tank vents normally , filtered with the charcoal and vented overboard in the frame rail, cleaned up. Without it you will just vent overboard and will get some fumes and perhaps fuel out the vent. If you still have it it may get fuel in it now and saturate it. Make sure the vent is not near the exhaust or you could have a fire if it overflows...be safe.

I do not have charcoal canister, just a straight pipe that is suppose to drip through a straight pipe through the floor. I dynamat’ed the floor so I need to re-find the hole. But I didn’t want to do that if I am plan to tee the vent into the fill elbow.

My assumption is that the vented cap is the same as the vapor separator, I.e., pressure should escape out the check valve.

Btw, exhaust is Y piped to a single pipe on the other frame rail so not a real fire risk.

I’m also no convinced vapor lock was caused by the vapor separator or fuel lines, rather more likely in the sniper unit itself as the MAT was 165.
 

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