Hello fiatforum

My friend reached out to me because his neighbors Uno couldn't start.

I said sure to give a helping hand.

We checked the spark plugs and all did ignite well, then we checked the fuel inlet and it seems to be fine to.

We tried to give it some start aid spray and it fired up but only when given the spray.

So I assumed it to be a fuel problem, so we took apart the intake, and all looked well, but when looking at the injector it didn't spray trying to start the engine, so we tried measuring the voltage to the injector and it was about 11,8V, then we tried putting 12V to the injector then It sprayed fine?
Anyone enlighten me please

Best regards Thomas

Hi,
Welcome to Fiat Forum.
I take it the car has single point injection. Normally these have a 12V supply on one pin of the injector with the ignition on and the ECU grounds the other pin to inject the fuel. If you measure the voltge it will be 12V on both sides with the engine stopped. It sounds like either the connection to the ECU is broken, a sensor input (crankshaft sensor?) is missing (faulty sensor or bad connection) or possibly a bad ECU.
I assume you have checked ALL the fuses? Checking the connection between the injector and ECU is next step.
Maybe someone with more knowledge of this model than me can give more detailed help.

Robert G8RPI.

Fuel pump working...?

Peter Pick-Up said:

Fuel pump working...?

Click to expand...

I assumed it is as the OP says the injector sprayed OK when 12V was applied directly to it.

Robert G8RPI.

Robert, you NEVER assume something....
Check it to be sure, all the OP did was powering the injector, he doesn't mention the fuelpump...

Peter Pick-Up said:

Robert, you NEVER assume something....
Check it to be sure, all the OP did was powering the injector, he doesn't mention the fuelpump...

Click to expand...

Hi Peter,
Bad choice of word, I deduced the fuel pump is OK as the OP states "then we tried putting 12V to the injector then It sprayed fine" If there was a fault with the pump, filter, or pipe work there would be no spray.

Robert G8RPI.