4.5 wont start

Nov 9, 2012
Olathe, KS, USA
The fuel pump does NOT run on these until the engine is cranking.

On the OBD2 trucks the cranking is confirmed by the cranks sensor. On the 93-94 trucks, it can run WITHOUT the crank sensor. It uses the distributor to monitor the cranking.

Since it just "died" when driving:
You said you have a CEL at Key On, so these SHOULD be good, but, check:
Fuses for EFI in fuse block
Fusible Links by battery for continuity.
Ground wires for the fuel injectors harness.
Check your voltage at the Fuel Pump Pins in the fuse block.
Jumper the fuel pump through the fuel pump relay pins in the fuse block to force the FP to run and determine pressure.
Check the wires on the plug on the top of the distributor to confirm there are no broken wires, the plug is fully seated.


Waiting for the Great Pumpkin
Mar 29, 2003
The fuel pump does NOT run on these until the engine is cranking.
Good to know, why I asked any of you OBD1 guys to check me.

Do your OBD1 setups have the same raw AL (silver) circular-shaped EFI relay in the underhood fuseblock that us OBD2 guys keep a spare of in the glovebox?

Or not?
Jul 8, 2020
port macquarie nsw
Fuel looks like a Diesel/Gas mix.....yuck. I don't believe our fuel pumps 'pre-prime' with key only at the 'on' position. I'm pretty sure they do not activate until the engine is cranking. But surely you have a fuel delivery issue as evidenced by the fact you can fog the engine with starting fluid and have it run.

While you may have fuel 'pressure' at the fuel rail it might not be enough pressure. 5-10 lbs of pressure squirting from a banjo bolt will look like a lot...but is not sufficient to run through the injectors. I think at this juncture a fuel pressure test is warranted.
thank you , that will be next on my list,
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