Crank but no start,no spark, has no pulse to

Or bad ground, try cleaning ground connections on fire wall

Hi Fred:
I;d be checking the cps.

is there power and ground to the coils?

If there is injector pulse than the crank sensor has to be good. Injector pulse and spark are both calculated off from the signal from the crank sensor.

Checking for power and ground to the coils is a good place to start. If that checks out than either there is a wiring issue in between the PCM and the coils or possible the PCM has failed.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

Ignition modules are pretty common on the 4.3 liters. Some things I would check are spark at the coil, power to the coil, pulse to the coil, and injector pulse. If you have injector pulse but no pulse at the coil chances are the module is the issue.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

If ECU has crank signal and engine turns over, ECU should give injectors a pulse and trigger the ignition. If not ECU might be bad. You should check power and grounds going to ECU. There are usually multiple power and grounds going into ECU

If you need further help, reach me via phone at https://www.6ya.com/expert/david_f2436a37cbb50365

Check for power on the + side of the coil with the key on Then using a test light check for a "pulse" on the negative side of the coil by attaching the clamp side of the test light to ground and the point to the negative side of the coil while cranking. If there is no pulse then it most likely needs a distributor. If there is a pulse but no spark then it needs a coil.

A test light connected across the coil primary leads should flash on + off when engine cranks(coil sparks when 12v turned OFF due to collapse of magnetic field).If you get pulsed 12 volts,and no spark from the coil,the coil is bad.If you don't get the pulsed 12 volts,trace back to find out why(the PCM turns the coil ground on and off,12 volts comes from switched IGN source)

No spark no injector pulse your saying you check pulse. With the key in the igition is there a key sign flashing and does the key have a battery for alarm. For the fuel pump to operate it need a crank signal so you got the crank correct but no spark so the crank works. Can you check the ignition for pulse you know how it is shape its curved on one side staight on the other side well the curve side and at that end is the ground after that on is the control from ECM. If you can check pulse there then we can go to the ECM . What I am trying to get at is this your alarm is the only thing beside the ECM that can cause this.

does it crank but not start or does it just click like dead battery or starter if it cranks check for spark and fuel pull spark plug wire and insert a screw driver and hold it close to an engine ground and have someone try to crank the engine is there a strong spark and use what is called a noid light it plugs into the plug for the injectors to see if the injectors are pulsing it should blink when you try too too start the engine if you have pulse and spark check for fuel pressure there should be a service port on the fuel rail that looks like a valve stem for a tire sort of youll need a fuel pressure tester if you had no spark or pulse at tthe injectors its most likely either the cam sensor crank sensor or the computor(pcm) if only no spark change the coil if that doesnt work you might need an ignition module but that requires more testing I cant explain here see a technician if no fuel pressure remove fuel filter drain and attemp to blow air through it if you cant its clogged replace and try vehicle if no start still feul pump is bad replace pump .

hope this helped

Check the fuse for the injectors, some vehicles have the injectors and coil running on the same circut, at the same time check the fuse for the ignition.