Technical Yet another Bravo 1.4 12v not starting

[NetEnforcer]

Hey guys!

I've been desperately been trying to put my Bravo 1.4 12v working but no luck. Sometimes it seems like it's close, but no cigar :bang:

This is what happened:

After changing oil, filters & spark plugs, the car gained a new life, so i pushed a bit. After switching from 3rd to 4th gear (going a bit to the redline), it died on me. I pull over and the engine dies. I turn the key over and the engine turns but it just won't start.

What i have done since then:

- Fuel pump: checked if there was pressure, indeed it has.

- All relays and fuses: checked, all work. Replaced them for precaution, no luck

- Put fuel directly on the throttle body (not directly, on the bottom) and the car starts and revs, so sparks and everything else runs fine

- According to fiat ECUscan, all the sensors are ok and replying (temperature, rpm, etc) and the Fiat CODE gizmo gives it's "ok" for start, so immobilizer should be fine

- That "inertia" button on the bottom of the seat is working, as i tried both with and without the button, making a shunt.

- There's tension and current when you turn on the key

What comes next?

So i checked the injector, as this darn thing is SPI. The first surprise is that the injector that was on the car was the wrong one . It was for a Peugeot 106 1.0. Basically:

What was on the car: Bosch 0280150686 469CC/min@3bar 1.3ohms
What should be on the car: Bosch 0280150699 752cc/min@3bar 6.7ohms

The one that was on the car was ruined, it was short circuiting. So i got a new one, the correct one and it won't inject (tested the injector out of the car, it works and injects, but on the throttle body it won't budge).
So i thought "well, maybe it will work with a wrong one" so i got exactly the same one it was on the car and it's the same.

Fears
Something on the ECU fried? Although from ECUscan everything seems fine, maybe the driver from the ecu fried with the short circuit that occured with the old injector?

Any ideas? I've ran out lol

Sorry for the long post :devil:

 

[bluejohn125]

A possibility...

I have a late model 1.4 ie Tipo.... a couple of years ago it had intermittent starting problems where sometimes it just would not go... it is a similar engine and injection setup as the Bravo 12V as far as I know (but 8V...)

Eventually it broke down away from home and the AA came and the guy had a really good look at it... like you say it was not spraying fuel.

He determined that the temperature sensor, connector and wiring were dodgy and that this was inhibiting the ECU's fuelling... I swapped the sensor and wiring and that fixed it.

So if your car has been butchered then you might look there (although you've no fault codes...)

J

 

[NetEnforcer]

Thank you for your reply!

Dunno if the Fiat ECUscan is reliable enough, but when I unplug the sensor, it gives 99º, when i plug it, it gives +/- the temperature that's currently in the air. If i take a couple of breathes and blow them to the sensor, the temperature rises 1 or 2º, so i think it is working!

But yes, the car has been severely butchered. The engine comes from a marea and the injector was from a peugeot.

 

[Adrian Bravo]

First I really like your post, that is some great detail and you have done some logical work.

I had a 1.4 12valve with a faulty throttle potentiometer / Position sensor for me it was an intermittent problem sometimes the car would turn over but not start, to make it start sometimes pressing the throttle peddle would work. I think my problem was the throttle potentiometer reporting the wrong throttle angle. You can see some details of that part here;
https://www.fiatforum.com/bravo-bra...v-throttle-potentiometer-position-sensor.html

Fiats manual here goes into great detail on your engine starting at page 102
http://download.fiat-bg.org/Books/Bravo_Brava_Marea/Bravo_Brava_Service_Manual/Bravo%20Service%20Manual%20Part%201.pdf

Also the manual talks about a Fuel Cut-Off function on page 108 controlled by a switch inside the idle control motor and some other parameters.

If the above over-run conditions exist, idle contact (1 - throttle closed) earths terminal 3 of the control unit, which cuts off fuel injection via terminal 21.​

Here is the pin out for the ECU. Maybe you could check if pin 3 is being permanently earthed?


So I think it is worth investigating the idle control motor and the throttle potentiometer. Maybe even damage in the wire between ECU pin 21 and the injector. Sounds like your car has an interesting past.

Hey guys!

I've been desperately been trying to put my Bravo 1.4 12v working but no luck. Sometimes it seems like it's close, but no cigar :bang:

This is what happened:

After changing oil, filters & spark plugs, the car gained a new life, so i pushed a bit. After switching from 3rd to 4th gear (going a bit to the redline), it died on me. I pull over and the engine dies. I turn the key over and the engine turns but it just won't start.

What i have done since then:

- Fuel pump: checked if there was pressure, indeed it has.

- All relays and fuses: checked, all work. Replaced them for precaution, no luck

- Put fuel directly on the throttle body (not directly, on the bottom) and the car starts and revs, so sparks and everything else runs fine

- According to fiat ECUscan, all the sensors are ok and replying (temperature, rpm, etc) and the Fiat CODE gizmo gives it's "ok" for start, so immobilizer should be fine

- That "inertia" button on the bottom of the seat is working, as i tried both with and without the button, making a shunt.

- There's tension and current when you turn on the key

What comes next?

So i checked the injector, as this darn thing is SPI. The first surprise is that the injector that was on the car was the wrong one . It was for a Peugeot 106 1.0. Basically:

What was on the car: Bosch 0280150686 469CC/min@3bar 1.3ohms
What should be on the car: Bosch 0280150699 752cc/min@3bar 6.7ohms

The one that was on the car was ruined, it was short circuiting. So i got a new one, the correct one and it won't inject (tested the injector out of the car, it works and injects, but on the throttle body it won't budge).
So i thought "well, maybe it will work with a wrong one" so i got exactly the same one it was on the car and it's the same.

Fears
Something on the ECU fried? Although from ECUscan everything seems fine, maybe the driver from the ecu fried with the short circuit that occured with the old injector?

Any ideas? I've ran out lol

Sorry for the long post :devil:

 

[NetEnforcer]

Hi Adrian! Thank you for your reply and insight!

I think i did not mention this on my first post, but i've tested out 3 "new" throttle bodies, and the problem is still the same. So maybe the potentiometer is ok (even pressing the accelerator, the car won't even try to start, it only turns)?

That tip on the pins is good, i'm going to see if i can test it!

Yes, this car has crashed against a roundabout and it damaged the oil sump. The previous owner did not notice and continued forward until the engine got stuck. New engine in...gearbox malfuncionted. It was swapped by Fiat without any expenses (it was a recognised design fault on these gearboxes, at least that's what i've been told).
The car started failing and the mechanic swapped for this Peugeot injector and the car was working. It still failed, but on my hands i've replaced the lambda sensor (that's new too) and all spark plugs & filters and it ran smooth.

Smooth until i hit it on the redline on 3rd gear. Weird thing happened: it was as if the rev limiter forgot when to cut. For example: rev limiter is at 7.000rpm's (just an aexample)...he went to 7.300 and abruptly it cut the rpm's to 7.000. When i shifted to 4th, the car died.

So yep, trying to recover this one, but it's not being an easy task!

Cheers!