1993 GMC Safari 6 cyl Two Wheel Drive Automatic 150000 miles

Recently got this van from my wife's Aunt. It ran perfectly until it was parked 6 months ago. It is a V6 model with fuel injection.

The engine turns over but will not fire. Fuel filter was replaced and the gas was dumped before parking and 10 fresh gallons added yesterday. When the key is turned to the on position you can hear the fuel pump come to life so it is functional as well. Pressing on the Schrader valve indicates that fuel is making it to that point in the system as well, under decent pressure. After pressing the valve, the engine will start for half to a full second and die. Then back to turning over with no fire. I tried adding a fuel injector cleaner thinking they may have been clogged by sitting for so long. No change to the problem.

Distributor has been checked as well and is functional. Spark plugs are in good working order and are receiving spark from the distributor. To be safe the ignition module was replaced today as well.

At this point I am at a loss as to what to do next. Any suggestions would be greatly appreciated.

Perform the tests in the link below:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-11.html#post2123675

Be sure to test all under hood and under dash fuses with a test light or multimeter. Remove and fully charge the battery--most auto parts stores will do this for free.

Thanks for the quick reply. Here are the results:

1. Battery test passed.
2. All fuses pass test with test light.
3. CEL operates normally.
4. Fuel pump is audible when key is put in On position.
5. Don't have access to a code reader and the van is immobile so I can't run the DCT.
6. Spark is good. ICM was replaced and there is no CPS in this vehicle.

Any other suggestions?

When was the last time that all of the spark plugs were replaced? Many people neglect the rear plugs. Only use the exact ACDelco plugs that originally came in the car.

Replacing the ICM was smart.

Clean the main ECM ground. Start testing key sensor reference voltages, as a proxy for testing the ECM. After that, consider replacing the coil packs and going over the electrical system very thoroughly.

Ensure that the spark plug wires are in good shape and are not shorting out.

Managed to get the van running. Filled up the gas tank and brought it to my house, about 20 miles away. Ran fine the whole way but now the engine knocks when accelerating. Idle speeds are fine and very low acceleration there is no knock. The knocking keeps time with the engine. I replaced the spark plugs and wires no change. It sounds as if the knock is coming from the center of the engine. V6 by the way.