Not starting, popping when turning over
 

Sorry for yet another 944 won't start post, but I have search, poked, prodded, and can't find the answer. I am hoping someone has some bright ideas. 1984 944.
Was running on Sunday for the first time in a while (not sure how long it sat before I bought it). Went to the gas station then took the kids for a ride around the block. Car died as I was slowing for a stop sign. It would start and idle but I could not give it any gas or it would backfire and die. Now it only sputters and pops when I try and start it. I have tried the Fuel Pump relay bypass, I changed the fuel filter, cleaned the fuel pump skimmer in the tank, and it seems like there is fuel making it to the fuel rail. I have not tested the fuel pressure, I have not pulled the injectors to see if they are outputting fuel. I have pulled a spark plug and I am getting spark.
Fuel filter was full of gunk and was a bit restricted, but tank looks clean now as is the strainer.
Do you have to bleed the fuel system or something like that?

Might be an electrical problem. Check your grounds. Your crank sensors on the bell housing and some of the other electrical parts and sensors. Good luck

I know this sounds stupid but it has happened many times to others. The color of the pump handles fools people into putting diesel in their cars when they thought it was the appropriate grade of gasoline. Green is theoretically supposed to be diesel but I've seen pumps where Premium was green. Just a thought.

I'd also check the connector on the AFM and TPS to see if it's loose or fallen off. Check the distributor cap to see if it's secure (easy for the bottom screw to come loose).

Check to see if your distributor rotor has come loose. It happened to me. Engine would pop when cranking. Locktite the screw holding the rotor in place. Hopefully it is still in the rotor, mine feel down in the belt guard and found it next to crank pulley.

The fuel injectors are clogged. Pull the fuel rail, clean the injectors, reinstall, and see what you get.

There are two sensors you might want to check: the TPS and the DME temp sensor. You can find test procedures for both on Clark's garage.

Try unplugging the TPS and starting the car - if the idle contact is broken that can cause problems. For the DME temp sensor, just a buy a new one from Pelican if you have doubts, it's cheap. When mine went bad (2 years old) I had very similar symptoms. https://www.youtube.com/watch?v=LON232b7F14

I hope it wasnt the ole diesel switch-a-roo. If you arent interested in investing in a fuel pressure gauge it is a lot cheaper to connect a hose to the fuel rail port and use a graduated cylinder. Buy an injector seal kit from our host before pulling the fuel rail, you will want to repace the O rings and caps.

You verified that you have ignition. Sputtering verifies that some fuel is getting out of the injectors.