89 2.9 ranger wont start.

[jrs89]

I was sitting in it one day and it died like i killed the switch. I thought maybe since it had less than a quarter of a tank that it may have ran out of gas. So i get some gas and nothing will spin over but wont fire off. Check the filter and it was dirty. New Filter. still nothing.. Spray the intake and it fires off. Checked fuel pressure at rail and it is good within spec. Have power to injectors. Made gas iv and it will run and rev up on gas in intake. Any suggestions? have spark fuel and compression.

 

[RonD]

If you have fuel pressure and hear the fuel pump run for 2 seconds when key is first turned on then most likely issue is computer is not Grounding Fuel Injectors to open them.
Fuel injectors get 12v when key is turned on but they have no Ground so stay closed, computer has two fuel injection Ground wires each running to 3 injectors, this is called Batch Fire Injection, 3 injectors are opened at the same time, Sequential fuel injection had 6 Ground wires and was used on later models.

When you crank the engine the distributor's sensor sends a pulse to TFI module to start and time the spark, this Pulse(PIP) is passed on to the computer so it can time the fuel injectors.
Computer needs the PIP signal from the TFI module to start and time the fuel injectors.
Sensor in distributor is working since spark is working but if TFI module is not passing PIP to computer then injectors won't open.

There is a good read here on the TFI system: http://www.therangerstation.com/tech_library/TFI_Diagnostic.shtml

The SPOUT(spark out) is a signal that comes from the computer to the TFI module, this allows the computer to set spark advance based on driver input, i.e. gas pedal position.

This is a diagram of the computer(EEC-IV) wiring: http://www.auto-diagnostics.info/ford_eec_iv
PIP is on pin 56
Grounds for the computer are not shared inside so each Ground pin must have a good connection to the body(Ground)