Technical Punto GT no injector pulse

[Franco505]

I suppose it depend where the injectors get their signal from.

I think the main clue its the ecu at fault ( though im not 100% ) is the readings from the injector plug ground pins to earth. They should be open circuit as the ecu supplies the ground to each injector as an when needed. All 4 of mine are reading 32Kohms... What I could do with is someone with a gt be kind and do a quick resistance check on their injector plugs for me to compare

 

[Steve gt]

Hi Francio , you sound pretty clued up working on the gt , I’d be happy to do a check for you but don’t have a tester , I could try and borrow one , what would I need to do to test them ?

 

[Franco505]

Hi Francio , you sound pretty clued up working on the gt , I’d be happy to do a check for you but don’t have a tester , I could try and borrow one , what would I need to do to test them ?

Hi, Im a bit rusty as I no longer work on cars but I did 10 years as a Ferrari Maserati tech lol. I work on dirty trains now lol!

All you would need is a multimeter set to resistance.
Do this with ignition off.
Unplug each injector and measure from the plug female pin to the battery earth. I got 32 thousand ohms which is a lot but I think it should be an open circuit. Plug them all back in after of course.

Don't worry if you dont get a chance I have a few more checks to do tomorrow before I condemn the ECU

 

[Franco505]

Update!

I just unplugged the crank sensor and measured I had power to it, white wire 4.7volts, black is ground wire and red signal. Keyed off and tested the wiring again from that plug. Black to chassis 0.3 ohms so straight to ground no issue there. White to ground 65kohms so nice and high no issue there. Red ( signal wire ) to ground 0.5 ohms.......

Unplugged ecu and tried again now open circuit.

Ecu has shorted the signal wire to ground internally, no wonder the injectors aren't pulsing, speedo not moving under crank etc. Im amazed the plugs spark tbh lol unless the coil gets fed some other way I dunno ... but all fingers are pointing to the ecu, harness is good everything seems ok apart from that and the high resistances read from injector plugs to ground with battery disconnected ( 32kohms ).

Now either swap another gt3 ecu in to test or just try and get it repaired and hope!

 

[Steve gt]

Can the ecu’s be repaired easily?
Where abouts are you located , I have a spare ecu .

 

[Franco505]

Can the ecu’s be repaired easily?
Where abouts are you located , I have a spare ecu .

There are places that can do it yes, but at the moment I haven't got found anyone that can deffo do it yet. Im in Essex mate, and you?

 

[Steve gt]

There are places that can do it yes, but at the moment I haven't got found anyone that can deffo do it yet. Im in Essex mate, and you?

I’m in Derbyshire, a bit too far away , hope you can get it resolved , I’ve seen a video on YouTube from Autosportivo and they have had a Fiat coupe ecu repaired I think

 

[Franco505]

I’m in Derbyshire, a bit too far away , hope you can get it resolved , I’ve seen a video on YouTube from Autosportivo and they have had a Fiat coupe ecu repaired I think

Would you be able to do a little test for me on your gt? Just crank the car and see if it does show a few hundred rpm whilst cranking like bugsymike said? I tried mine today and its as flat as a pancake ..

Cheers