my sons 1980 4 cyl with CIS fuel injection won't run. I first had problems with the fuel pump relay not working and replaced it. Now the fuel pump runs while cranking the engine. The cold start injector works good. I pulled it out and it sprays a nice pattern during cranking. It seemed to be good so we reinstalled it put a good battery in the car and it started and idled pretty good until my son tried to drive it and it kept cutting out until finally it wouldn't start. We towed it home and replaced the fuel filter it seemed a little plugged (hard to blow through but it was wet). Car still won't start.

I tried the below steps (suggested by I think it was Mr Fraser from a previous thread I had about checking fuel pump pressure). There was no spray pattern from the No. fuel injector. I tried moving the air meter and there was no change. I removed the outlet from the fuel filter and usen a hose I tried to pump a reasonable amount of fuel into a can. There was not very much flow, maybe a half quart per minute, maybe. It surely didn't seem like 70 psi worth of fuel flow. The question is that if there isn't enough input pressure can it cause the fuel distributor to not put out any fuel? This is about to cause me to pull out my hair.

Have you looked at the injector spray patterns. It should be a very fine spray at idle and increase with movement of the air meter. A technique for doing this is to pull out one injector and slip a 3 ft. piece of clear vinyl tubing over the end. Stick the other end into a 20 oz. plastic soda bottle. Then you must plug the hole in the head. I use a black rubber plug I found at the hardware store where I bought the tubing. Start the engine and observe the spray. Try revving the engine a little also.

Alternately you can test all 4 injectors at once by pulling them all and installing tubing and bottle on each. Instead of running the engine, pull the main fuel pump relay and jump the two connections to the pump on the socket ( pins 30 to 87 ). You can then vary the flow by moving the air meter by hand. The advantage here is you can tell if the injectors are flowing the same volume by comparing the fuel in the bottles. You can also check that there is no leakage from the injectors when the air meter is at rest.