‘87 454 TBI, NO Fuel spray, HAS fuel pressure, has 12v @ injectors, has spark

[beady]

You need to check the fuses,in the box checking for power on both sides of the fuse Technically that's not checking the fuses it's checking the fuses and power to the circuit. But a good fuse with no power to it still won't get the job done.

The truck starts and runs on starting fluid.

I don’t know which circuits are powered with the key in each position offhand. Does every fuse have power to one side of it all the time?

I’m new to this platform so don’t have the background knowledge of reading posts for decades like on my BMWs and 300zx.

So ecm 1 fuse connections have power to the inner leg with key ON and power (12 v) at both fuse terminals metered on the back of the fuse in ON.

Ecm b has no power at either of the fuse block terminals (metering the actual fuse block terminals with fuse pulled) in ON.

 

[beady]

It looks to have a remanufactured ecu if that helps point to something.

 

[Ricko1966]

The truck starts and runs on starting fluid.

I don’t know which circuits are powered with the key in each position offhand. Does every fuse have power to one side of it all the time?

I’m new to this platform so don’t have the background knowledge of reading posts for decades like on my BMWs and 300zx.

So ecm 1 fuse connections have power to the inner leg with key ON and power (12 v) at both fuse terminals metered on the back of the fuse in ON.

Ecm b has no power at either of the fuse block terminals (metering the actual fuse block terminals with fuse pulled) in ON.

Ecm b has no power ever that's a problem. And yes for a fuse to work it has to get power in and power out. It's time to investigate. Some fuses are only powered up with key on so check that and then research ecm b circuit

 

[gmbellew]

surprised it would run on fluid if ecmb has no power at the fuse panel? ecmb powers the ecm and the fuel pump, that's it. Orange wire in the harness, goes to ECM and fuel pump relay and splices into the oil pressure switch for a backup to the fuel pump relay. if the fuel pump is running, but ecmb fuse has no power, PO has maybe re-engineered something?

 

[beady]

So from tracing the circuits on the schematic, it looks like I should have always on +12v at two pins on the bulkhead connectors. Circuit number 2.

Only one of the pins has continuity to the positive terminal (the connector in row Y in this pic). The other one, at the bottom left, does not have continuity.

Any thought before I start pulling wires out of the loom to see what I see?

Edit: I think it’s the wires coming off the starter/solenoid. There’s also a fusible link right there. Pretty tight up there, tempted to just get a new, smaller high high torque starter to give me more room if I have to remove the starter.

 

[beady]

Could be onto something here, lol. Wires were pinched by the sheet metal starter heat shield.

 

[squaredeal91]

Could be onto something here, lol. Wires were pinched by the sheet metal starter heat shield.

Definitely could be just the answer

 

[beady]

So to close the loop, I repaired those two positive wires and the issues went away. Scanner can talk to ecu and reports no codes now. Truck starts and runs normally now (besides the idle not quite being dead smooth).

I’m going to pull the tbi and rebuild it and replace injectors (Delco) and pressure regulator since I already bought the kit and injectors.

Mike