Avital 4103 in my 94 chevy 1500

I appreciate all input. And all the elf so far thank you guys still a work in progress I guessThebackyardmessup

"this old carbed 350 should fire"... Is it carbed? I would think a '94 would have fuel injection, either throttle body or separate injectors. You just had the fuel pump replaced? That might be a clue. Was it a new pump used? If there is a valve in the fuel line test the fuel pressure. Probably looking for about 50 psi. Does it have an external fuel filter? May be restricted. Sometimes the whole tank should be cleaned when a pump is replaced. Using caution, you could try putting a little gas down the carb or throttle body (but not while cranking- in case it backfires) and see if it is a fuel issue. Hold plug wire(s) about half an inch away from ground while cranking to check spark. Did you do a compression test? If cylinders are even but low you may have a jumped timing chain. If you have fuel, spark, and compression/valve timing it should start. One of those might be missing. Hope this helps...

A 94 will have one coil, a conventional distributor, and 2 TBI type fuel injectors. There is no "rail" or pressure test port on a TBI engine. Fuel pressure should be 9-12 psi at idle. I check fuel pressure by inserting a T for my gauge after the fuel filter down on the frame. You say you have spark. Perhaps you really don't. A very difficult to diagnose malady on these systems is a bad pick-up coil in the distributor. NOT the Ignition Coil that makes the High Voltage, but a little coil inside the distributor. Has green and white wires, and plugs into the module in the bottom of the distributor under the cap. The coil should be 820 Ohms. If you find higher resistance, it has failed and can be causing your no-start. To replace this coil requires removing the distributor, driving the pin out of the gear, and removing the shaft. Most guys just get a replacement distributor from Vato Zone. If you suspect fuel pump is not running, there is a test connector on the RH side of the firewall. Under the plastic cover, if it is still present. There are 4 relays, and one of them will have a short wire with a female terminal on it. Apply 12V, and the pump should run. The fuel pump circuit is usually GRAY on GM's, but the trucks may be red. I don't remember which. Probably gray. There.

It would be nice to hear back from the original poster to let us know if he found the problem and what it was. At one point he referred to it as - this old carbed 350. Maybe not the original motor? Would be nice to know what the problem was or possibly he hasn't fixed it yet.