Fuel system question???

[TDAWG1]

1987 GMC JIMMY so first year TBI 350 engine done for swaped in 454 from a 70 model Chevelle everything is good needs some work but my question is. When I unhooked the fuel lines @ the the engine, then reinstalled to the Carburator except for the return line. I dont know what to do with it? I dont want to cut it out because I am going back to EFI at some point.

Last BB I drove over to MOAB from JUNCTOWN the way we go VIA gateway engine temp between 210 and on a long pull around 230. Had the wrong carb on and some other tunning issues just trying to make it to BB lmao. On the way home Climing up Castle valley Began to smell Fuel made it to the top. Shut off engine open Hood Fuel squirting out of return line.

Also I added 3" exhaust Close to tank which I plan to fix, But also on passenger side almost if not touching fuel filter clamp... WHat do you recomend using to disapate heat at those points and can I just cap off return line, or leave it uncaped cause at this point I think its acting as a vent tube... a little lost here even though I feel its a simple solution... Thank you for your help

 

[ktmoutfront]

Cap the fuel line and use a vented filler cap. Has vent somewhere.

 

[rebelgregory]

Cap the fuel line and use a vented filler cap. Has vent somewhere.

What he said^^^. I was gonna say put one of those cheap valve cover vent filters on the return line and use it as a vent, but if you have had fuel spit out if it before, then that means your return line is submerged in the tank. This may be true for all TBIs, I don't know. But if that's the case, any time your tank pressurizes, it will spit out of the return line. If the return line just ended at the top of the tank (with nothing inside the tank submerged), then it would be an acceptable vent.

 

[TDAWG1]

I have a vented cap... I gotta learn not to tighten so much I think

 

[TDAWG1]

Thankx for the info IM on it. Wheeled a little today with only a few issues... not this one though

 

[76zimmer]

So what do you do in a rollover with a vented cap spilling fuel out?
Bad idea IMO.
IIRC....the factory system had the tank vented to the charcoal EVAP cannister which had a sourced vacuum on it from the TBI. The filler cap also has a vacuum breaker in the cap which will allow vacuum in the tank to pressurize to a given value set from the factory.
That return line could be used to vent the tank, providing it has no low spots to collect fuel, but it should have some kind of vented rollover protection as well.

 

[ktmoutfront]

My 87 is not vented to a charcoal canister. Unless it vents through the TB.

 

[76zimmer]

all vapors had to be recovered so it must vent somewhere or burned in the engine.