Technical Grande punto 1.9 multijet, 2006. warm start problem

[Pribi]

Hello,
I own a fiat grande punto 1.9 multijet, 2006. Im writing here because i dont know what else to do about my problem. The car wont start when the engine isnt completely cold. In a -5°C weather and with cold engine it starts completely normal but then it neads at least 4h cool down time until it will start normally again. So even if the engine is a little bit warm it wont start. I changed the fuel pump, checked fuel flow, changed temperature sensor (because when it doesnt start it shows an error in which states that the cooling fluid temperature is too high), checked the battery (which is also new), checked the car with different diagnostics and everything seems to be fine jet it doesnt start when warm (if its very warm it starts normally, it doesnt start just when its half warm). When the car doesnt start, I pop the hood up, disconnect the temperature sensor and the car starts fine (u can hear the fuel pump pumping for longer when i disconnect the temp. sensor). I dont know what else to check so if anyone had the same problem i would appreciate the help.
Thank you in advance.

 

[chris3234]

Does it just soon over but not sound like it's trying to start?
If so I'd check the cam/cranks sensors

 

[DGPunto]

Worth getting hold of a copy of MES (link) and see what codes that gives you

 

[Pribi]

It cranks as much as i like but wont start, im puzzeld about why does it start when i disconnect the temp sensor

 

[Pribi]

About the MES, do you think it would give me something different than DELPHI diag?

 

[nikrox]

it is FIAT specific....

 

[levemircento]

About the MES, do you think it would give me something different than DELPHI diag?

I have a delphi clone diag [multidiag] as well as mes, to be honest they both do the same things, the multidiag is just a little more clunky to use

its puzzling that it wont start without unplugging the temp sensor, you say you changed it for a new one, and still the same?

was it brand new or used? it might be worth buying another [sorry, I dont know how dear they are] and trying it

google your local common rail diesel specialists, send them an email or ring them up, I am sure they will be happy to advise over the phone or email, thats what I would do in a situation like this.

let us know how you get on

 

[bernih]

hi Pribi, my 2007 1.9 Sporting has done that since I bought it nearly four years ago.
It always starts first time of the day all year round, but if I only drive it for five minutes and try to start again it spins & spins for ages.
What works for me is to treat it like a full cold start again which means I turn on ignition and wait at least ten seconds before I try to start the engine - no matter what time of year or outside temperature is.
A few times when it still has not started I have to spin it three or four times (20 seconds each) before it starts. On the first spin it sounds like it's never going to start, second time it coughs a bit and third or fourth time sort of drags itself into life.
I thought I saw on here that it's a `special feature' of these cars and just live with it.
Sorry that isn't a `technical' solution but it works for me.
You say you've checked fuel flow and fitted a new pump, but have you checked the fuel pressure? Try connecting a pressure gauge in a fuel line in the engine bay and see what readings it shows
1) primed before cold start
2) primed before half-warm start
Disconnecting the temperature sensor may set the ecu to a default cold start setting, but I don't know that for sure.
On cold start the `coolant temperature too high' warning will come on when the sensor supply voltage drops too low due to engine cranking, i.e. it's a false warning. You should also get a power steering fault warning at the same time, for the same reason.
Good luck, let us know if any of this helps

 

[Pribi]

I have a delphi clone diag [multidiag] as well as mes, to be honest they both do the same things, the multidiag is just a little more clunky to use

its puzzling that it wont start without unplugging the temp sensor, you say you changed it for a new one, and still the same?

was it brand new or used? it might be worth buying another [sorry, I dont know how dear they are] and trying it

google your local common rail diesel specialists, send them an email or ring them up, I am sure they will be happy to advise over the phone or email, thats what I would do in a situation like this.

let us know how you get on

Yes, the sensor is brand new, it doesnt cost that much so i bought a new one and fitted it, im hesitant to buy another and change it again because its a lot of work to take it out with the tools i have, i talked with multiple mechanics and they are all puzzeled, one advice that i was given that i think is the best one is to check the wiring for rusting, the mechanic said that rusty wires give a lot of resistance and when the car is half warm it can mess with the temperature sensor and then the pump doesnt give enough pressure to the engine

 

[Pribi]

hi Pribi, my 2007 1.9 Sporting has done that since I bought it nearly four years ago.
It always starts first time of the day all year round, but if I only drive it for five minutes and try to start again it spins & spins for ages.
What works for me is to treat it like a full cold start again which means I turn on ignition and wait at least ten seconds before I try to start the engine - no matter what time of year or outside temperature is.
A few times when it still has not started I have to spin it three or four times (20 seconds each) before it starts. On the first spin it sounds like it's never going to start, second time it coughs a bit and third or fourth time sort of drags itself into life.
I thought I saw on here that it's a `special feature' of these cars and just live with it.
Sorry that isn't a `technical' solution but it works for me.
You say you've checked fuel flow and fitted a new pump, but have you checked the fuel pressure? Try connecting a pressure gauge in a fuel line in the engine bay and see what readings it shows
1) primed before cold start
2) primed before half-warm start
Disconnecting the temperature sensor may set the ecu to a default cold start setting, but I don't know that for sure.
On cold start the `coolant temperature too high' warning will come on when the sensor supply voltage drops too low due to engine cranking, i.e. it's a false warning. You should also get a power steering fault warning at the same time, for the same reason.
Good luck, let us know if any of this helps

Yeah i did get the power steering warning a few times, i didnt check the pressure but i did check the fuel flow and its ok, i can hear the fuel pump pumping so i always wait for it to finish but it still doesnt start (thats for the cold start thing that you said), thank you for the advice, i will keep you posted when i go to the electrician