Technical 1996 Fiat Brava 1.4 12V Not starting

[PuntoEvoBoy]

Hello. I have recently bought a 1996 Fiat Brava 1.4 12v from a friend after it failed on her.

The current situation is crank and no start.
When I turn the key, the red "injection" and orange "CODE" letters come on, code light turns off after a couple of seconds and the injection light turns off soon after, however, there is no spark and the fuel pump does not activate when cranking, I suspect a fault with either the immobilizer or an important sensor or wire.

I've already pressed the fuel cutoff switch and the fuel pump works when I jump the relay, but doesn't work when trying to start the car.

I've put together some wires to connect my DS150 scan tool to the car. It shows no errors (Data list attached below).

The data list shows some useful data, namely:

• Engine rpm sensor -> when cranking at full swing, it reads 250 to 275 (I'm guessing the crank/rpm sensor is good and in the correct gap). If I unplug the sensor, it always reads 0.

The following data seems to be related to the immobilizer:

• Engine start up -> Allowed
• Key (transponder) -> status Programmed
• Universal code -> Not achived

The first two seem ok to me, does anyone know what "Universal Code -> Not achived" mean?

On the data sheet Air inlet temperature sensor is blank (that's because I had previously disconnected the injector/air temp sensor) in order to see if the fault reader was reporting real data. Normally, it shows a temperature similar to the ambient temp.

Can anyone help me with this issue?
Thanks in advance for any help.

 

[PuntoEvoBoy]

Solved it! It was the orange wire connecting the fuel pump relay to the ignition coil. So, a single broken wire was preventing the car from getting fuel AND spark.

I made a makeshift connection just after testing this particular wire with a multimeter and having no continuity between the coil and the relay and the car worked like a charm.

I'll remove the wire cover and actually fix or replace it when I have the time.

 

[PuntoEvoBoy]

These are the damaged wires in the engine harness. I've also tested the secondary resistance on the coils and they had a Resistance of around 10.000 Ohm, when the expected values for these coils are around 12000 to 14600. Also, the ignition fuse (the big one) originally was 40A, but the one in the car was a 60A. My guess is that the fuse burned (because of a coil that was drawing more current than normal) and some "mechanic" just installed a bigger fuse without testing anything. Luckily the damaged affected just a few wires (burned the orange one completely, and other 3 wires were lightly burned on the insulation, but were working normally). I took the harness out of the car and repaired all affected wires with heat-shrink and new wires.

After putting the harness back in the car, I also replaced the ignition coils and replaced the fuse with the correct one. After that, the car started normally and ran like a charm.

Good thing the burning of the wires didn't completely destroy the harness (or the car, for that matter).

I hope I can help someone diagnose their car with a similar problem in the future.

Thanks, everyone!