My sons 88 240 wont start.
Son claims it was starting to occasionally run sluggishly in prior month I was away. Prior to that it started very easily, and ran very smooth. Then he started it in the drive way, pulled out, it sputtered and he drove down to the end of the block and it stalled. Had to push it back to the house. Have not been able to get it to start since.

What have tried and tested.

Fuel-
Fuel pump tests fine - Dead head press 90 psig. - Pressure holds for 20 min before press decay to 80 psig.
Fuel rail pressure looks fine - after cranking - pressure is 36 psig. During crancking 38-41 psig a little high? Pressure decay is good.
Injectors are firing. Pulled fuel rail and injectors are blowing up a storm.

Friend suggested pulling connector on Mass Air Meter - it tried once to start for a second and then nothing. Ohm check on Mass Air Meter is .4 ohms - manual says 0-1000 ohms is ok?

Compression -

Tested good - 160 psig all cylinders

Spark -

Looks ok based on plug pulled and put plug on coil wire, and jumped BC terminals on the distributor connector to the control module, and plug fires.
Electronic module ground is good with ignition off - 0.2 ohms, but seems like with ignition on there is some voltage leak back to the Bosch Electronic ignition unit ground wire, because ohmmeter reading goes up to 2.3 ohms?

Voltage at ignition module tests good.

Other -

The resistance on the Coolant Temperature Sensor tests at 4.3K ohms. This is high. Book says at 50 F should be about 2.1K ohms.

Have ordered new fuel pump relay, although pulled and cleaned some corrosion.

Seems like engine is getting too much gas - too rich and flooding? But tried to throttle gas to fuel rail to reduce pressure - did not work.

My car does not have the diagnostic module (started with 89?)

Need help ideas before I give up and tow to a shop. Worried that local shops not too much better. Dealer says he would have to replace the wiring harness at $2500 and would not work on it.

Any help appreciated.

Oldguy