I have no injector impluse

check the compresion in all cylinders 100 psi (compression good) check the spark -check the fuel pressure.30 psi at gauge with switch on.(if no keep pressure with switch off injectors or fuel pressure regulator are bad
check the signal to the injectors (get little injectors tester at autoparts) if no signal check the ground to the injectors black wire
or the other wire (computer)= good signal to injectors and good fuel pressure and good spark (defective injectors)

What testing have you done?
I looked at info for 94 blazer 5.7L engine.
Do you have spark, everywhere? Did you use a gage And check fuel pressure, with tbi fuel injection 9--13 psi. With throttle body injection you should be able to see fuel injector/s spray pattern, both fuel injectors. Even if injector/s spray pattern looks good, 5 psi won't start and run a v8.
Check for applicable trouble codes. My info shows your obd1, so you should be able to check some codes, yourself, if there are any.
You need air--fuel--spark--compression, proper amount at the proper time and it should start.

Fuel pressure regulator . plugged fuel return line .

With the ignition switch ON and the fuel pump running, the fuel pressure indicated by the fuel pressure gage should be 333-376 kPa (48-55 psi).
The Fuel Pressure Check determines if the fuel system is providing fuel pressure. The components involved include the fuel tank, sending unit, pump, pipes and hoses, pressure regulator, fuel rail, and injectors. Also checked is the electrical operation of the fuel pump relay. This chart requires J 34730-1A , Fuel Pressure Gauge J 37287 , Inlet and Return Fuel Line Shut-off Adapters.

Check fuel line for pressure - there should be something like a bike tire valve on fuel line - press the inner part of it and see if gas spurts out hard. If so you have pressure , a working fuel pump, and gas is reaching the injectors.

Check out the igniter?

Cam Sensor Failure Causing no Start or Stalling : Dodge ...

repairpal.com > Problems > Dodge > Durango
Dodge Durango Cam Sensor Failure Causing no Start or Stalling. ... On the 4.7L V8engine, the Camshaft position sensor failure can cause the engine to crank but not start or it can ... On the 5.9L V8 engine, rerouting the ignition coil wire and spark plug wires can help solv. ... 1999 Dodge Durango ... Drove good till put gas.

check for 2 things, CTS, and the injector, reason, if the injector is clogged or misfiring, you can still have and issue, i`m a mobile mechanic, if you`re in the long beach area email me back

If you need further help, reach me via phone at https://www.6ya.com/expert/reginald_d1f35dc049b0256a

REPLACE FUEL FILTER,CHECK FUEL PRESSURE, SHOULD BE SHOULD BE 9 - 13 PSI TBI FUEL INJECTION AND 55 - 61 PSI MFI FUEL INJECTION.WHEN YOU TURN ON IGNITION WITH ENGINE OFF.LET FUEL PRESSURE BUILD UP AT FUEL PRESSURE GAUGE TO CORRECT PRESSURE THEN TURN OFF IGNITION SWITCH. IF FUEL PRESSURE DROPS VERY FAST OR LEAK DOWN IN 10 MINUTES.YOUR FUEL PUMP CHECK VALVE FAULTY IS BAD.FUEL PUMP NEED REPLACING.BE SURE FUEL INJECTORS ARE CLEAN THEY WILL LEAK DOWN FLOOD ENGINE FOUL OUT SPARK PLUGS.

stand outside your van,reach in the window and turn your key over,but not to the start position. you should hear a whirring sound from the rear of the van and it should last about 2-3 sec. this will be your fuel pump powering up. if you dont hear it,then you have a bad fuel pump. Dodge Caravans from 96-01 are VERY bad about eating fuel pumps. if the pump is fine,have someone try to start it while you look under hood and see if injectors are spraying fuel. if the pump is good,and you have no spray from the injector,then you have a clogged fuel filter which will need replaced.

A couple of things to check, when the engine is turning over, do you have spark? You can disconnect one of the spark plug wires, insert a screw driver in the end of the wire, hold the screwdriver 1/4" away from the block, crank the engine over and see if you have spark.
If you do have spark, borrow or purchase a fuel pump pressure gauge ($40 to $50), connect it to the fuel injector rail test port (looks like a tire valve stem with a cap on it) crank the engine over and record the fuel pressure. You should have 55 to 60 PSI. Make sure it does not leak down more than 5 PSI after you stop cranking the engine.
Good luck, let me know.
Regards,

1. Test Fuses. Test both under hood power distribution center and the fuse panel under dash. This is done with a test light tool. The test light should illuminate on both sides of the fuse, if not the fuse has failed and needs to be replaced.
2.Testing Fuel Pressure Test for proper fuel pressure with a test gauge on the fuel rail, most throttle body injection cars (TBI) are between 13 psi and 17 psi. and most (DPI) direct port inject systems are between 40 psi and 55 psi. If no or little fuel pressure is observed and there is 12 volt power present the fuel pump, the fuel pump needs replacing.
3.Checking Timing Belt Test for compression by removing a spark plug and insert a compression gauge. Crank the engine over about 5 seconds the gauge should read between 125 psi and 165 psi, if no compression is observed remove front engine cover to inspect timing belt or chain. Crank engine to observe cam rotation, if the cam does not rotate the timing belt or chain has failed. (note: if the timing belt drives the water pump it is best to replace the water pump at this time)
4.Test for Injector Pulse Remove injector connector to insert injector test light (node) or volt meter. Observe light flash or gauge pulse while cranking. If light/voltmeter doesn't respond, an ignition distributor/crank angle sensor (CKS) or an ignition module is most likely your problem.
5.Test for Ignition Spark Remove spark plug wire, insert an extra spark plug into end of wire, rest spark plug next to a ground source then crank engine. You should observe a blue spark between the spark plug gap and ground source. If no spark is observed, an ignition coil, ignition rotor or spark plug wires might have failed. (always keep hands away from engine when cranking)