i have a 4.3 vortec just bought. i got it home after alil sputtin on drive and now cannot get to start. it has a new fuel pump, sending unit, and tank, along with distributor, iginition module, cap, rotor, plugs, wires, fuel pressure regulator, and spider injection. all these components worked good together for bout week and now i still have spark, air, and fuel but results in cranking but no fire. ive hooked gemini with pathfinder system up and every sensor is working properly but the rpms read 9999 while motor off and key in on position. there is no change in rpms even while cranking over.
i am new to site but very familiar with s10s so looking for some input as this is a new condition ive never delt with.

 

update just put new ecm in and have same results. only thing left that i can think would be some wiring gremlin.

 

Try pulling the injector harness wires - the blue and red ones that go into the front of the manifold through a gromet. Thats an 8 dollar part and should always get changed when doing the spider. The wires that contact the injector nubs are thin like hair, I had a crooked one that made my truck not start sometimes, and just quit at random.

 

injectors r workin perfectly they pulsate like supposed too. but im only gettin a change in rpms when i lift and wiggle distributor, and its not a constant change or steady. is it possible for a coil to arc on inside and send constant power threw tach wire to read such a high rpms?

 

ohsofly
i replaced the ground wires at the back of the motor and got it to fire up and it still had the stutter to it. but ur correct on those wires they were the second issue to the problem.
so thanks for the advice

 

Good job. Sucks when its an 8 dollar part thats keeping you from runnin.