Technical Crank no start

[Donsfiat]

Have a gas powered AT,NON TURBO,2013 500,will always crank till battery drains,but will only start 50%of the time,have changed plugs and coils,and oil change. SO FAR

 

[Ralf S.]

You don't mention that it stinks of petrol, so it sounds like it's not getting enough fuel.

Is the fuel pump working properly (is fuel coming through the lines when you crank it) and is the injector firing (does it have a signal when you're cranking)?

Also.. check the spark plugs are actually sparking. If you have no fuel injection signal and no sparks (with power at the coils) then it could be a crank position (TDC) sensor.

Ralf S.

 

[Donsfiat]

You don't mention that it stinks of petrol, so it sounds like it's not getting enough fuel.

Is the fuel pump working properly (is fuel coming through the lines when you crank it) and is the injector firing (does it have a signal when you're cranking)?

Also.. check the spark plugs are actually sparking. If you have no fuel injection signal and no sparks (with power at the coils) then it could be a crank position (TDC) sensor.

Ralf S.

Thank you Ralph, no sir it DOES NOT STINK OF PETROL ""ALTHOUGH IT DOES OFTEN SEEM AS IF IT MAY BE FLOODED?"", The fuel pump does work, Also I have installed new iridium spark plugs as well as 4 new coil packs for them. There is a signal to the fuel injectors as well."HOWEVER I DID ORDER A NEW SET OF INJECTORS THAT I WILL INSTALL WHEN THEY ARE DELIVERED" I did not think about the CPS as a problem though, I didn't realize a CPS could work intermitently. It's a low cost part and easy to replace so I will clean the area and replace it today.

 

[Ralf S.]

If you're getting a signal to the injectors then it would suggest that the CPS is working okay... although they do break down and become moody and there's no real way to check them. They're solid state, so tend to work better when they're cold, and become less reliable when they're hot. I don't know if that fits in with what your car is doing.

Do the coils have power, and do you get a spark from the plugs (if you rest a spare plug on top of the rocker cover and crank the engine)? No spark when you have power at the coil is a classic CPS symptom.

If the injectors and the plugs are sparking then it must start as long as the injectors have fuel in them... so the next thing would be to look at the fuel pressure. When you say the fuel pump works, did you check the fuel was actually coming out of the fuel pipe at the injector rail, or did you just listen for a sound at the pump? Sometimes a pump can buzz and sound alive, but it isn't delivering enough petrol. If, when it starts, does it run normally.. or is it down on power or faltering under load etc? If it runs fine, then the pump is likely okay.


Ralf S.

 

[fixfiat]

Had the same issue.
Here are the magic things I did that finally got it working (no particular order):

• Replaced the starter
• Oil change
• Replaced spark plugs
• Removed air intake
• Replaced crank (cam?) sensor
• Replaced fuel pump
• Tried bump starting it by pushing
• Left spark plugs out and hood open to air out engine
• Sprayed starter fluid down each spark plug hole (let it dry and then put spark plugs back in)
• Sprayed starter fluid into the air intake piece (going directly to the manifold)
• Cranked it and gave it some gas

Not sure what the magic solution was, because it finally started after trying to bump start it and then trying the starter spray method.
After that it had a slight misfire. Used an OBD2 app to reset the sensors and positions and it was golden.