Hey guys, in need of some help....

[brian022687]

Hi guys, so I am new here and I wanted to get a couple of other opinions for this. Well a couple of weeks ago my girlfriends 97, 5.7 Tahoe stopped working. She drove it out to the store, and on the way she said it sputtered once, but after that it ran fine. She got to the store and after coming back out the truck would not turn over. She had been having a problem for about week prior to this with the truck starting kind of hard. Well she had the truck towed to a garage after it would not start and the garage told her that the fuel pump was gone. Well last weekend I had the truck towed to the house, and I replaced the pump. The new pump is working properly, the lines are pressurized but still the truck will not turn over. I thought I had narrowed it down to the fuel injector spider, and today I replaced that. However the truck will still not turn over. The car is producing spark, but it appears as if the fuel isn't getting into the cylinders. Is there anything I could have missed, maybe something electrical because that is the only thing I can think of. Is there maybe a fuse or a relay to specifically control the injectors, because the fuel pump is still working fine. Any help I could get here would be great,

thanks guys

 

[retorq]

Pull the cap and look inside, there was a dude here a few days ago that had spark but it wasn't enough to start the engine. Can you verify fuel pressure?? Maybe a fuel filter change is in order.

 

[SunlitComet]

There is a fuel pump relay under the hood in the relay box and ensure you ave the new design pump and followed the instructions to modify the wiring. The ground wire for the pump is located to the left of the tank on the frame rail. When you say it will not turn over are you saying the will rotate but not start or will not even rotate.

 

[retorq]

Yeah it won't rotate but he's somehow getting spark.

 

[brian022687]

No, the truck will rotate, but it will not start, and I don't have a pressure tester so I can't verify accurate fuel pressure, but I do know that once the key is turned from off to Assc the fuel pump dose kick on and pressurize the lines. Once this happens and I check the pressure release located just before the fuel lines go into the injectors it dose have good pressure, I was doing a little bit more looking and I was thinking it might be the crank sensor, a couple of symptoms match what I have going on so I was going to check that today to make sure that is good

---------- Post added at 06:46 PM ---------- Previous post was at 04:56 PM ----------

so update, I know for a fact it isn't the crank postiton sensor, I took one off another tahoe that is running perfectly and the truck still will not start, and the other tahoe started fine with the crank sensor I pulled from this one

 

[SunlitComet]

Your pump should not pressurize when moving the key backwards to the accessory position only when turned to the on position. that could indicate something wrong with the ignition switch unit. You are gonna want to put those crank sensors back where they came from or you will have another issue to deal with later. You can borrow a pressure gauge from autozone or oreily auto to test the pressure but the actual pressure must be know and should be around 60 psi. One thing that comes to mind is you may have blown a fuse to the electronics somehow. Those fuses are located in the underhood power block and are labelled on the inside of the lid. Perhaps the fuel filter is clogged.