Technical Fiat Croma 1.9 mjet weak start when cold

[DB4323]

Hello. I bought 2009 fiat croma 1.9 mjet 150 hp 1 month ago with 1 problem. Car when its cold engine it need very long cranking to start engine. Sometimes even on 2nd or 3rd cranking would start. When its heated engine at least 1 minute it start normally.

When we take down jack from sensor of coolant temperature car start perfectly on cold engine start.

What i did with several mechanics (me and past owner):
New battery, new car starter, new alternator and dpf and egr software off and probably few more things but i forgot which one.

I did: changed injectors (two different sets of injectors i tryed), did dpf and egr off software 2nd time with different map, tryed other used pump in tank (didnt had new), new sensor of coolant temperature, new rpm sensor, new maf sensor, new map sensor, new fuel filter, new air filter, new oil, new main belt (i dont know correct word), new sensor of pressure of fuel (that thing that is behind engine).
Injectors (my own) was on 2 bosch services for checkup, they said it was ok.
Glow plugs working it was checked. There is no error on car at all. I spend tons of time, money and my nerves.
I tryed different battery its the same.

Smoke from exhaust is black, only when cold and that long cranking its grey.
And i repeat again, when we take down sensor of coolant temperature car start normally when its cold.

If someone have sugestion what should i check (or re check) i would be thankful.

This is how it start. I shut down engine on end of video

 

[bugsymike]

Hello. I bought 2009 fiat croma 1.9 mjet 150 hp 1 month ago with 1 problem. Car when its cold engine it need very long cranking to start engine. Sometimes even on 2nd or 3rd cranking would start. When its heated engine at least 1 minute it start normally.

When we take down jack from sensor of coolant temperature car start perfectly on cold engine start.

What i did with several mechanics (me and past owner):
New battery, new car starter, new alternator and dpf and egr software off and probably few more things but i forgot which one.

I did: changed injectors (two different sets of injectors i tryed), did dpf and egr off software 2nd time with different map, tryed other used pump in tank (didnt had new), new sensor of coolant temperature, new rpm sensor, new maf sensor, new map sensor, new fuel filter, new air filter, new oil, new main belt (i dont know correct word), new sensor of pressure of fuel (that thing that is behind engine).
Injectors (my own) was on 2 bosch services for checkup, they said it was ok.
Glow plugs working it was checked. There is no error on car at all. I spend tons of time, money and my nerves.
I tryed different battery its the same.

Smoke from exhaust is black, only when cold and that long cranking its grey.
And i repeat again, when we take down sensor of coolant temperature car start normally when its cold.

If someone have sugestion what should i check (or re check) i would be thankful.

Compression check?

 

[DB4323]

It was checked i forgot numbers. And as i said without coolant temp sensor start normally. After start engine works normally

 

[bugsymike]

It was checked i forgot numbers. And as i said without coolant temp sensor start normally. After start engine works normally

With sensor disconnected do you think the ECU is guessing and going for a high or Excess fuel setting?
I am "old school" if a diesel has fuel, good compression and working heater plugs , when cold it should start. I would still like to know how near manufacturers figures compression readings are.
As you will know another name for a diesel engine is CI or compression ignition, low compression - no ignition, especially in cold weather and after you have checked most everything else.

 

[DB4323]

Ok i will try to find someone to check my compression again. Thanks
Someone told me for that coolant sensor when unplugged if car start normal without sensor its some software problem.

 

[bugsymike]

Ok i will try to find someone to check my compression again. Thanks
Someone told me for that coolant sensor when unplugged if car start normal without sensor its some software problem.

I think with most sensors when disconnected the ECU goes for a "safe" option, such as when you disconnect the MAF sensor on an engine, it runs but not perfectly.