Marcos Beltran
OBS Enthusiast
Anybody have any idea what would cause the truck to start with the fuel line disconnected? Thats the only way it will start consistently.
Starting and Acceleration Issues
- Thread starter Marcos Beltran
- Start date
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stutaeng
I'm Awesome
I'm assuming you disconnected the return line? You should get fuel out of the return line when you put the key ON: that normal. I think it's the smaller of the 2 hoses.
Otherwise if you disconnect the feed/pressure line, engine will not get fuel.
Marcos Beltran
OBS Enthusiast
No it definitely was/ is the line feeding fuel. I hooked a rubber line to it and fuel came out with pretty good pressure and it was the larger line.
highwaystar
I'm Awesome
Replaced O2 sensor?
stutaeng
I'm Awesome
Well, that doesn't make sense! The other line should not have pressure from the pump, so how does the engine start and run. You mentioned you replaced the fuel pump. Maybe you got something crossed? Remove both lines and see which one has pressure. I think the FP has a check ball somewhere that prevents fuel pressure loss on the return line. Maybe somehow you are getting pressure there?
Did you check to see if the pressure hold with Key On Engine Off (no cranking)?
Marcos Beltran
OBS Enthusiast
Not yet. Havent put a scanner on it, doing that tonight.
Marcos Beltran
OBS Enthusiast
Okay let me explain a little better. This all happened before i replaced the pump. The truck would not start on its own so this led me to believe it was not getting fuel. So i got a rubber hose and connected it to the larger hose that goes directly into the manifold. Had my son crank the truck just to see if fuel was getting to that point and into the manifold. Well when he cranked it, the fuel filled about half a mason jar which put to rest the idea that i wasnt getting any fuel to the engine. While doing that the truck turned on which surprised the sh** out of me. So i quickly told my son to shut it off and put the gas that was in the jar back into the tank. Just to see if it would happen again i told my son to start the truck again and sure enough it started again. I didnt run the truck for more than 3 or 4 seconds with the fuel line disconnected. So i shut off the truck and reconnected the fuel line, reassembled the breather and cranked the truck on. It ran around the block came back turned off the truck off and restarted it. Turned off and on the truck for 4 more times and it started everytime with no problems. On the 5th try it wouldnt start. So i repeated the process and everytime the truck started that way and would last for 5 off and ons then would not start again. Thats when i did a fuel pressure test and thought it could be the fuel pump. Replaced the fuel pump and truck ran beautifully for 15 minutes then it came back. So yeah i know it makes no sense at all.
Weird things happen to vehicles that sit up for some time. Sounds like something is plugged up. Be it a return fuel line, or the cats, IDK. I have seen a dead bee get into a fuel line, and plug up the line so that it wouldnt let the gas flow at enough pressure to keep the truck running. It got hung up inside the fuel filter. So the truck would run for a little while, the the bee would get sucked up to the output line and plug up the flow. Once the truck died, the bee would fall back into the filter. Truck would start and run fine untill the bug would get sucked up again. Just 1 example of what can happen. I know you changed the fuel filter, but some times you have to think out side of the box.
Marcos Beltran
OBS Enthusiast
Can you elaborate on that? Not sure i follow.
