Chevy Truck Won’t Start Lots of Fuel at TBI

fuel pump problemMy fiancĂ©’ bought a 1994 Chevy 3/4 ton 4×4, 5.7L, V8. the throttle body is dumping fuel into the motor. He changed the plugs, wires, distributor, cap, rotor, fuel1 filter, and computer. He checked the timing and it’s good. All this with no result. He also bought a book on this truck and had a mechanic look at it.

He only bought the truck 3 days before this happened. He was driving home from work and it just stopped.

Any ideas? He’s spending all my money and his time trying to fix this and it’s not working. I would greatly appreciate any help you could offer!!

Thank you,
Holly

Hello Holly,

The best thing to do is start from scratch here. He has to be missing one of the main ingredients to start the engine, spark to the spark plugs, proper fuel pressure and ignition timing and compression.

If he can see visible fuel coming down the throttle body, my only concern would be is it at the proper pressure. He can rent a fuel pressure gauge from the auto parts store and screw it on to the engine and crank the engine over to test fuel pressure.

You can also bang on the bottom of the fuel tank with your fist or rubber hammer AS someone cranks the engine over, this can jump start a weak fuel pump. Even though you have fuel visibly coming out of the throttle body does not mean you have enough fuel PRESSURE to start the engine.

If he is sure he has proper fuel pressure, the next thing to do is check for spark at each spark plug. If there is no spark, check the ignition coil and the ignition module and distributor for spark.

If he has spark and fuel, then this might be a compression or timing chain issue. Sometimes the engine will spin over faster and sound funny when the timing chain breaks or there is internal engine damage.

Before he spends any more money on this I would highly recommend he tow it to a qualified mechanic and have them diagnose the problem. He can do the work himself once he knows what the problem is.

Please share this with your friends,

Austin Davis

Posted in: Won't Start Issues

12 Comments on "Chevy Truck Won’t Start Lots of Fuel at TBI"

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  1. Chris pfeffer says:

    I have a 93 Chevy with a 5.7 liter. Has spark and fuel but when try to crank it the injectors dump to much fuel causing it to flood motor. Any ideas on what could be ? Thanks

    • Austin Davis says:

      Are you sure you have spark on all cylinders? Have you checked compression on all cylinders, or ignition timing….does it sound funny when the engine cranks over, like a timing chain that has jumped a tooth???? Its pretty hard to “eye ball” the proper fuel spraying from the injectors. You might want to rent or borrow a manual fuel pressure gauge from the auto parts store and screw it into the fuel rail at the back of the engine to test fuel pressure at the engine. Could be a bad fuel pressure regulator, but we dont see that very often. We usually see weak fuel pumps the most on these vehicles…you could visually see fuel at the injectors, but not have the proper pressure/volume to start the engine. Can you start it using starting fluid?

  2. Joseph says:

    I have a 94 3/4 pickup that will start and run fine it once in a while won’t start at all. If left overnight it fires up. Any thoughts?

    • Austin says:

      I the engine will turn over but not start I would be suspect of a weak fuel pump. You can sometimes bang on the bottom of the fuel tank with your fist or block of wood as someone cranks the engine over. If it starts you need a new fuel pump. You could also have a no spark issue caused by a bad ignition module which tends to fail more when it gets hot. It controls spark to the spark plugs.

  3. Alex says:

    That happened to my 94 s10 and had the spark, and the fuel, and the right compression but still wouldn’t start. So i got a friend of the family to take a look at it and he checked everything, and now to the good part, he unbolted the exhaust pipe from the cat converter and it fired right up. So try that man hope i could help

  4. Travis says:

    Put a new fuel pump on it about two years ago .I might try the ignition module but is there a way to wire the coil up to see if the computer maybe the problem

    • Austin says:

      Possible but doubtful on a bad computer. I would suspect the module or fuel pump which are both high failure items on these trucks.

  5. Travis says:

    My father enlaw has a 1994 1500 that will not start has fuel no spark has power to coil but no spark . first I checked the distributor cap and rotor they were bad changed them still no fire. took the ignition module had it tested it was good changed the coil still no fire then I changed the pickup coil and still no fire timing chain isn’t broke and the distributor gear is good do you think it might be the computer or Mabe something else

    • Austin says:

      I think the best thing to do next would be to replace the ignition module. I have not had much success with “testing” them. I would also buy a cheap “noide” light that you can place on the end of the spark plug wire to light up when there is a spark. they are cheap and makes checking for spark much easier. Any auto parts store with have one. You might have spark that is hard to see, but dont have fuel. These trucks are notorious for bad fuel pumps. Sometime banging on the bottom of the fuel tank with a rubber hammer AS someone cranks the engine over can kick start a weak fuel pump.

  6. don says:

    i have a 95 z-71 that starts right up but wont stay running! new distribitor rotor,fuel filter,plugs,tbi’s dumping gas. how much fuel pressure does the pump need to put out? have to work the pedal to keep it running! seems like it running out of gas to me… i give up! just runs good for a second then dies then starts right up run for a second and dies

    • Austin says:

      I would be a little suspect of a weak fuel pump, which are common on these trucks. Sometimes you can bang on the bottom of the fuel tank with a block of wood while the engine is running to help kick start a weak pump. Best way to replace the pump is to remove the truck bed to gain access to the tank.

  7. Don says:

    Ihad the same problem wi9th my truck. Found out it was the heat sencor it cost 5.00 dollars o put or less it took
    about five min to put it in and now is working like a new truck!!!

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