tbi carb issue? - I have a 95 silverado tbi 5.7L, my question is where do the 2 lines on the back of the carb go. I believe the one ...

I have a 95 silverado tbi 5.7L, my question is where do the 2 lines on the back of the carb go. I believe the one on the drivers is the inlet and comes from the fuel tank throught the filter then to the carb. where does the other line go? I had to move the lines around to get my carb back on and I was curious where that one line went, and if I messed something up because the truck won't start now. Just trying to narrow things down, I just installed a fuel gauge on the the inlet line, but don't know what the other line does.........

I just put in a new IAC valve and a new fuel pressure gauge and now my truck won't start. I can see gas dripping from one of the injectors on the tbi, but it won't start. I just cranks and it has never done that........any ideas?

Did you check all your electrical connections after working on it?

I agree with jepics- check your electrical connections- starting from the most basic stuff on up... keep us posted, and hang in there!

I took my time and bolted and plugged in everything and double and triple checked everything. It's possible something got moved or unpluggged. There were only 2 plugs on the carb and 4 hoses. I have to get this truck started.......

Double check your fuel flow by losening the main line and turn the key enough to run the pump.

What does the return line do? by moving the return line around to get it to fit into the carb, is it possible I did something to it to make the truck not start. I know it's probably a stupid question, but I'm running out of ideas. I have ground effects on the truck, so I can't see where it goes to underneath. It's outside still surrounded by snow..........

I don't know if I mentioned it or not, but I hear the pump and when I crank it, both injectors are spraying. If I move the key forward the fuel pressure gauge goes up to around 11 for about 5 seconds then goes to zero......

OK, b/c you asked I'll post a 101 in throttle body (fuel) injected (TBI). Maybe understanding how the system works will help in your troubleshooting.

The fuel pump in your tank will maintain a constant pressure no matter what the engine RPM's are. The two fuel injectors in your throttle body (TB) will only take as much fuel as the computer tells them too based on throttle postion and other readings. So, since there is a constant pressure going to the TB, what fuel is not used goes back to the tank via the return line. Both lines run down the back of the engine and down the frame to the fuel tank sending unit.

If the truck has sat for a while, it may be worth it to get a rebuild kit and replace all of the O-rings. It's easy and cheap.

How did you plumb the fuel pressure gauge into the system? It sounds like your fuel is passing right through the TB. Double check your connections. making sure you didn't leave anything out or cross the tubes. The TB is marked "In" and "Out".

You have the eys on this one. All I can do is throw ideas at you.

Good luck!

Can a moderater combine his posts to create less confusion and overlapping information?

Topics combined.