Technical Help my Fiat 500 Abarth won't start

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Technical Help my Fiat 500 Abarth won't start

suptempo

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Hey guys, I have read may topics regarding fiat 500 not starting and tried many of them and still cant seem to figure it out. So I am turning to you guys for any advice.

My car is a 2010 fiat 500 Abarth, bone stock. I was driving, and the car suddenly turned off and turned back again. Then it was ok for some time. After a while car didnt turn on and sometimes it turned off while idling or driving. I took it to 2 really great mechanics (different shop), they put it on the tester and nothing came up. i took it home and wanted to drive it to the electric shop to check out if its something electrically related. Now it wont start at all.

I checked the sparks and they are sparking. i took the fuel off the rail and the fuel is pumping. Car is cranking really good. Battery is 98% healthy and fully charged. I did put the air cover off and sprayed some brake cleaner in it and the car started and ran really poorly and after a couple of seconds turned off again. So I removed the fuel rail and injectors. Clened them up and checked each one individually and they click when i put some electricity to them. I then resembled the rail and put it back in and nothing happened again. I did hear the fuel pump priming the rail and pressurizing it. after another failed attempt i then pulled the injectors out and while still on the rail and connected to power i observed the injectors while my friend tried to turn the car on. nothing happened, no fuel was spraying out of the injectors. now my question is if that is normal? i thought there would be fuel spraying out of the injectors when cranking the car.

do you guys have any other ideas what else i would need to check? i am really stuck here and dont know what else to do.

any help would be appreciated. Thanks
 

RedAbarthMTA

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possibly low oil ? Sounds as if low oil pressure is not allowing the ecu to activate the injectors. Just a guess on my part but these engines are a lot more sophisticated than we assume they are.
 
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suptempo

suptempo

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I did get the oil light the first time it happened and i took it to a mechanic. I had oil and oil filter replaced. Checked the oil level now and the oil stick shows normal level of oil... will check again tomorrow morning when i can see better. Thanks
 

A3jeroen

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Sounds to me like the cranksensor doesn't provide the signal that the engine is turning. No code is generated since the ECU doesn't know the engine turns.

gr J
 

Dave R

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I did get the oil light the first time it happened and i took it to a mechanic. I had oil and oil filter replaced. Checked the oil level now and the oil stick shows normal level of oil... will check again tomorrow morning when i can see better. Thanks
 

Dave R

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spark and fuel are timed by ecu which gets info from sensors. Unless you have a cam sensor, if the crank sensor fails the ecu assumes the engine has stopped so won't operate fuel pump. Usually it stops the spark as well - so it's a bit strange. It seems that the pump is not getting an instruction to work from the ecu. Can you get the pump hotwired to see if it will then start?
 

koalar

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I was driving, and the car suddenly turned off and turned back again.
Is that the car stopped running and started again on its own

Or

Did the car stop running and would start back up by turning the key


When it stopped what warning lights came up. Did everything come on as per putting the key in the ignition. Oil pressure, engine check, abs or just a few

Or was it a sudden loss of power that came back


Now it’s not working, if you look carefully at rev counter can you see it moving slightly as it cranks. You could also look at the live data from the crank sensor on a cheap scanner

Did you have or had any recent electrical problem such as having to reset the clock, start stop stopped working all the lights and electricals work as they should
 

koalar

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Thinking out loud

Sparks plugs are firing HT is okay

Spark plugs are firing ECU getting signal from crank sensor

Fuel rail is pressuring pump is okay

Injectors aren’t switching

My next move would be to check the injector are getting power from the relay
 

A3jeroen

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It is my understanding that fuel is cut off when the engine is not turning (cranksensor signal) to prevent the fireball that is always displayed in bad movies after a car hits a tree.

gr J
 

koalar

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It is my understanding that fuel is cut off when the engine is not turning (cranksensor signal) to prevent the fireball that is always displayed in bad movies after a car hits a tree.

gr J
To fire the spark the ECU need to know when

It must be getting a crank single unless I am missing something obvious
 

koalar

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What I don’t understand is why the ECU hasn’t detected a fault in the wiring. One injector or two injector not pulsing and the car will still start although like a bag of nails

Same relay as the coils so must be okay to this point

The injectors are on a separate loom

If each injector is receiving battery voltage

Either the immobiliser is on not quite sure how this works might stop everything including spark

Or

Break in the wiring to the ECU would be my best guess
 
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John202020

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Could the rear hatch wiring have fried something? Given its age?
Immobiliser wouldn't cut the car off whilst driving?
 
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suptempo

suptempo

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I changed the sensor today. It was like 25euros so I changed it just for the peace of mind. Still nothing... when the car works, it turns on a first crank. now even if i try for like 15 seconds, nothing happens.

Is that the car stopped running and started again on its own

Or

Did the car stop running and would start back up by turning the key


When it stopped what warning lights came up. Did everything come on as per putting the key in the ignition. Oil pressure, engine check, abs or just a few

Or was it a sudden loss of power that came back


Now it’s not working, if you look carefully at rev counter can you see it moving slightly as it cranks. You could also look at the live data from the crank sensor on a cheap scanner

Did you have or had any recent electrical problem such as having to reset the clock, start stop stopped working all the lights and electricals work as they should
I was on the highway doing like 110km/h and it started stuttering and it felt like it jumpstarted itself. the second time it did that the engine and oil light came on. That is why i went and changed the oil because i thought i didnt have enough oil or something like that...

The electrics worked normally, i just got a warning light for the front light quite some time ago. i dont have a start stop so i cant say anything about that.

Correct

Forgot about that detail

Voltage to the injectors would be next test
Could it be that some wires on the ignition could not be ok? i know that the first owner (i am the second one) had a tracker on it. and i saw the wires were soldered onto ignition lock wires. i did check all the wires again and they are not touching and are isolated pretty well. but maybe that could be causing some problems...

also sometimes when the car didnt start i unplugged the battery and it didnt help. I also disconnected the ECU connectors and sometimes it started. i am thinking it could be the ECU.
 
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suptempo

suptempo

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What I don’t understand is why the ECU hasn’t detected a fault in the wiring. One injector or two injector not pulsing and the car will still start although like a bag of nails

Same relay as the coils so must be okay to this point

The injectors are on a separate loom

If each injector is receiving battery voltage

Either the immobiliser is on not quite sure how this works might stop everything including spark

Or

Break in the wiring to the ECU would be my best guess
You think a wire could be damaged? i checked the loom and cosmetically looks good.
also when i removed spark plugs to check them out, i cleaned all the wires for the connectors that are in the plastic holder on the engine, they were dirty but not damaged.

Did the car stop running and would start back up by turning the key

And when the car turns off by itself, i usually couldnt start it back up by turning the key. I usually disconnect the battery and the connector a couple of times and it turned on. Sometimes only 2 tries were enough, sometimes it wouldnt start for like a couple of days.
 

The Panda Nut

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I seem to remember a recentish thread about a faulty oil level sensor causing this on an std 500 and no error codes showed up.
 
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suptempo

suptempo

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I seem to remember a recentish thread about a faulty oil level sensor causing this on an std 500 and no error codes showed up.
I will order one tomorrow. its super cheap, so it cant hurt to change it as well.
 
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