Technical Difficult starting when left overnight or a few days.

[124spiderman]

Hi all,
My 09 has developed a small annoying thing.
When I leave it overnight or a couple of days I crank the engine it won’t start up on first cranking. It will however start up second time. This only happens if I leave the car overnight or for a few days.
It’s as though it has no fuel.
My initial idea was stale petrol but now I’m thinking it could be something else as I’ve topped up with fresh fuel.

 

[varesecrazy]

Hi.
A suggestion..

Turn the ign. Key to MAR..
let the tank pump run ( it should supply fuel for 5 to 10 seconds before stopping)

Then try.

How long does it tend to run for?

My diesel runs for a while compared to my petrol FIAT'S.. But it has double the mileage.

Charlie

 

[aurick86]

My 09

That doesn't tell anybody much
What engine are we talking about?

 

[Craig830]

Had this on a Rover K-Series.

It was the engine coolant temperature sensor for the ECU. The sensor for the dashboard gauge and the one for the ecu were seperate, not sure on the t-jet though.

Check the readings on MES and let us know your results

 

[124spiderman]

That doesn't tell anybody much
What engine are we talking about?

Sorry.
1.4 TJet 150hp.

Only does when sitting overnight or few days.
Will not start on initial cranking. Takes a couple of goes.
Then its good for the day.

 

[aurick86]

My initial idea was stale petrol but now I’m thinking it could be something else as I’ve topped up with fresh fuel.

Finish ALL the fuel then add fresh petrol.
It sounds like the really well known t-jet cold start problem....same basic symptoms.

 

[edesl]

Hello,
Please tell me more details, what is the well known starting issue?
I have T-Jet 150
and I experience sometimes, 4th 5th attemption is starting the engine up.
Thanks a lot

 

[MikeG20]

Try few times MAR-off without crancking. 4-5 Times, wait for fuel pump to finish.
Then cranck.

 

[edesl]

Why is this? Does the petrol flows completely back into the tank?
Seems, in my case, when the tank is 3/4 - full , it starts well.
If the petrol level is lower than 3/4, then the issue comes.
Can this be due to the check valve? Why the 4-5 seconds of initial priming of the fuel pump before cranking is not enough to "re-saturate" the fuel line? Where could the air enter into the fuel system? Thru a leaky injector?

 

[MikeG20]

I think that two things can be;
1. "weak" fuel pump/return valve-needs few seconds to reflow at full pressure

2. fuel injectors leak-mixture is too rich at start

I have same isues.
Starts better when tank is 3/4 full

 

[varesecrazy]

You can always tead the fuelrail pressure values via the OBD port

 

[aurick86]

You can always tead the fuelrail pressure values via the OBD port

No you can't!
T-jet's don't have fuel pressure sensors.


https://www.fiatforum.com/bravo/454876-fiat-bravo-problems-wit-first-starting-engine.html

 

[aurick86]

I think that two things can be;
1. "weak" fuel pump/return valve-needs few seconds to reflow at full pressure

2. fuel injectors leak-mixture is too rich at start

I have same isues.
Starts better when tank is 3/4 full

Starts better with 3/4 tank because there's more fresh fuel.


2.NO. mixture is too lean at start-up... test it yourself, by adding a little extra fuel (from a engine start spray).

 

[MikeG20]

But there is no logic, engine starts after 3 or Max 4 crancks. Then works rough Like on 3 cilinders. That lasts for Max 10 seconds.
Always pour min. 10 liters od fresh fuel every month, only 100 octanes
I tought that on my case its LPG related (evapourator od LPG ibjectors leakage), but same problem when driving only on Petrol for month od two

 

[aurick86]

But there is no logic, engine starts after 3 or Max 4 crancks. Then works rough Like on 3 cilinders. That lasts for Max 10 seconds.
Always pour min. 10 liters od fresh fuel every month, only 100 octanes
I tought that on my case its LPG related (evapourator od LPG ibjectors leakage), but same problem when driving only on Petrol for month od two

It starts better after a few tries because some fuel adds up in the intake, wetting the valves, and eventually there is enough fuel to start.

I know the feeling, i've been dealing with this for a few years(i also use LPG).
The car is in perfect mechanical shape.. all sensors are working correctly... and there is absolutely no problem, checked fuel pressure, fuel flow..etc etc etc etc.

The only thing i can imagine is that even a few liters of old fuel spoil the new one much faster.. so drain the tank out... wipe it clean (can be done if you remove the fuel pump)... add new fuel.

Even when the engine stalls from fuel starvation there are still 2-3 liters of fuel in the tank...it's just inaccessible o the pump.

 

[MikeG20]

Well, it makes sense.
But 100 octanes fuel is more resist to "spoil" i think.
Im thinking even to replace fuel pump, Bosch, complete assembly (case with fuel level sensor) cca. 150 euro.
Cant find info only for fuel pump inside assembly

I even start thinking that is related to outside temperature.
Today, 12 degrees celsius outside, starts without problem, one cranck, no rough idle.
At 16°C day before had rough idle.
Maybe IAT sensor

 

[aurick86]

Pump can be checked:


I've actually replaced mine with one from a fellow Bravo Club member's car... nothing changed... his car started fine with my car... mine still didn't.

Sensors can be checked with MES.

 

[edesl]

unfortunately, any leaking injector can let enter air into the system and the fuel from the hose could go back to the tank. But why the hell the pump is not able to refill the system fast..... ?

 

[aurick86]

If an injector were to leak on a t-jet it will pour a lot of fuel into the intake manifold....some of it would evaporate but it will probably bend a rod next morning.

That would also mean that the engine would start fine after priming the system a few times (key to on, wait 10 seconds (yow will hear the pump shutting off), off..repeat 5 times).

 

[Joe0586]

Just run a battery test. It will also tell you the alternator performance.