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It’s been a while since i last posted, so here is a little update:
At one time i replaced the crank sensor.. that did nothing.
It had gotten so bad it would die 3-4 times after each cold start;
I took it to the Fiat Dealer.. they had it for 4 mornings. They concluded that since nothing was obviously wrong, and the fact that it runs fine after it heats up, that the ECU must be faulty.When i heard that I took the car away and payed for the “diagnostic”
About a week ago I emptied the gas in the tank and put it in a different car.
I then put fresh gas in.. after that it has started each time in the morning.. but it still sputters a little after start.It’s been a while since i last posted, so here is a little update:
At one time i replaced the crank sensor.. that did nothing.
It had gotten so bad it would die 3-4 times after each cold start;
I took it to the Fiat Dealer.. they had it for 4 mornings. They concluded that since nothing was obviously wrong, and the fact that it runs fine after it heats up, that the ECU must be faulty.When i heard that I took the car away and payed for the “diagnostic”
About a week ago I emptied the gas in the tank and put it in a different car.
I then put fresh gas in.. after that it has started each time in the morning.. but it still sputters a little after start.Hi,
I’ve measured the temperature sensors in the morning, they are closer, only 5 degrees difference as opposed to 8.
Tried playing around with resistors on the temp sensors ( got them almost identical – close to the actual temperature) but there was no change in the behavior when starting the engine.
So..it’s probably not the temperature sensors.Also I’ve checked to see if it’s loosing injector pulse or spark when it’s starting to die. It’s not loosing spark and it’s pretty strong. As the engine starts to die the injector pulses get longer( maybe trying to supply enough fuel to keep it alive).
Had a look in the repair manual at the fuel pressure testing procedures:
Supply pressure check:I don’t understand how it would have more pressure with the engine started idling, since the intake vacuum would make the pressure regulator open sooner. What do you think? is that part correct? -maybe it should be tested at full throttle not idle (when the boost would force the regulator closed to make more fuel pressure in the fuel rail)
Anyway my results are 3 bar after 1-2 seconds after i turn the key to the on position, 2,7-2,8 bar at idle, and 3,5 bar at full throttle.Return pressure check:
Why would there be any pressure on the return line after the regulator??? since it’s a straight pipe directly to the fuel tank and there it just dumps inside, and an even bigger volume of fuel is being sucked out of the fuel tank by the fuel pump( it’s bigger because some of the fuel is burned in the engine)
Is this some crude way of measuring volume??My measurement on this was a big ZERO bar pressure.
I would take it to a professional, if i could find someone who i could trust.
Here they are all about reading fault codes and replacing parts, Nobody does diagnostics.
Last time i had a problem with this car(it has a feature called “Hill Hold”- holds the brakes for 3 seconds after you release the brakes, if you are on a hill… mine would hold the brakes indefinitely ) i took it to a Fiat dealership and they couldn’t even reproduce the problem( even tho i gave them all the info) so they decided that i should replace the entire braking system, abs pump,brake pump… and all at a cost of ~3000 euro.
Of course I refused to do that, and after spending 300 euro’s on a second hand ABS pump+controller ( thinking that Fiat might have been right- they weren’t problem was still there ) …anyhow long story short i fixed the problem with a 1 cent washer between the brake pump and the servo!Hi,
I’ve measured the temperature sensors in the morning, they are closer, only 5 degrees difference as opposed to 8.
Tried playing around with resistors on the temp sensors ( got them almost identical – close to the actual temperature) but there was no change in the behavior when starting the engine.
So..it’s probably not the temperature sensors.Also I’ve checked to see if it’s loosing injector pulse or spark when it’s starting to die. It’s not loosing spark and it’s pretty strong. As the engine starts to die the injector pulses get longer( maybe trying to supply enough fuel to keep it alive).
Had a look in the repair manual at the fuel pressure testing procedures:
Supply pressure check:I don’t understand how it would have more pressure with the engine started idling, since the intake vacuum would make the pressure regulator open sooner. What do you think? is that part correct? -maybe it should be tested at full throttle not idle (when the boost would force the regulator closed to make more fuel pressure in the fuel rail)
Anyway my results are 3 bar after 1-2 seconds after i turn the key to the on position, 2,7-2,8 bar at idle, and 3,5 bar at full throttle.Return pressure check:
Why would there be any pressure on the return line after the regulator??? since it’s a straight pipe directly to the fuel tank and there it just dumps inside, and an even bigger volume of fuel is being sucked out of the fuel tank by the fuel pump( it’s bigger because some of the fuel is burned in the engine)
Is this some crude way of measuring volume??My measurement on this was a big ZERO bar pressure.
I would take it to a professional, if i could find someone who i could trust.
Here they are all about reading fault codes and replacing parts, Nobody does diagnostics.
Last time i had a problem with this car(it has a feature called “Hill Hold”- holds the brakes for 3 seconds after you release the brakes, if you are on a hill… mine would hold the brakes indefinitely ) i took it to a Fiat dealership and they couldn’t even reproduce the problem( even tho i gave them all the info) so they decided that i should replace the entire braking system, abs pump,brake pump… and all at a cost of ~3000 euro.
Of course I refused to do that, and after spending 300 euro’s on a second hand ABS pump+controller ( thinking that Fiat might have been right- they weren’t problem was still there ) …anyhow long story short i fixed the problem with a 1 cent washer between the brake pump and the servo!I don’t have access to an oscilloscope, but i might do a DIY soundcard/laptop oscilloscope but i will only be able to measure up to max 12v ( would rather apply max of 2-3v).. but that should be enough to see the patterns of the crank and cam sensors. I will not be able to measure the secondary ignition.
It’s not a vacuum leak, it uses a MAP so it will adjust fuel to the pressure in the intake manifold. Also i’ve pressure tested it while i was testing for boost leaks.
Eric, I do agree that the sensors should measure closer.. i will take another measurement, one morning before it gets any sun, so the temperatures should be much closer.
If that is still 8 degrees C, off than i will try to make it closer to what the other two sensors ( climate control and intake) are reading; i will add the necessary resistors in parallel or series till i can read a closer temp on the obd interface. I think this should be ok, since the coolant sensor is basically a thermistor (temperature controlled resistor)I don’t have access to an oscilloscope, but i might do a DIY soundcard/laptop oscilloscope but i will only be able to measure up to max 12v ( would rather apply max of 2-3v).. but that should be enough to see the patterns of the crank and cam sensors. I will not be able to measure the secondary ignition.
It’s not a vacuum leak, it uses a MAP so it will adjust fuel to the pressure in the intake manifold. Also i’ve pressure tested it while i was testing for boost leaks.
Eric, I do agree that the sensors should measure closer.. i will take another measurement, one morning before it gets any sun, so the temperatures should be much closer.
If that is still 8 degrees C, off than i will try to make it closer to what the other two sensors ( climate control and intake) are reading; i will add the necessary resistors in parallel or series till i can read a closer temp on the obd interface. I think this should be ok, since the coolant sensor is basically a thermistor (temperature controlled resistor)I know, you’re probably right.
About those reading there is a difference of 8 degrees Celsius, to me that seemed ok because the car was sitting in the sun when that was taken. Made sense that the air would be hotter.
The basics, I’ve checked them 3-4 times each.
I don’t think it’s the fuel delivery because:
-pressure is good;
-LTFT is ok;I’ll post back as soon as i have some more info, maybe a video so you guys can see exactly what is going on (suggestions on video content would be welcomed)
I know, you’re probably right.
About those reading there is a difference of 8 degrees Celsius, to me that seemed ok because the car was sitting in the sun when that was taken. Made sense that the air would be hotter.
The basics, I’ve checked them 3-4 times each.
I don’t think it’s the fuel delivery because:
-pressure is good;
-LTFT is ok;I’ll post back as soon as i have some more info, maybe a video so you guys can see exactly what is going on (suggestions on video content would be welcomed)
Yaw and steering sensors are used by the ESP system, so if fitted that will not work.
As long as you don’t have an error light i think the ABS should work (you should test it).Yaw and steering sensors are used by the ESP system, so if fitted that will not work.
As long as you don’t have an error light i think the ABS should work (you should test it).[quote=”umbergbr” post=104819]I had a similar issue with a truck I used to have. It would act strangely after a fill up or on cold starts. It ended up being a bad fuel pump module. Nothing wrong with the pressure it had to do with the evap system. Somehow raw fuel was getting drawn up into the system and when the solenoid would open to dump what was supposed to be fumes it was dumping fuel into the intake system causing it to sputter and die. Once the engine got hot it would vaporize the fuel prior to it entering the cylinders.
[/quote]I already thought about that.
The evaporative system is separate with a charcoal canister next to the tank and line to the valve, it’s not connected to the fuel pump at least in my car.
So one evening I unplugged and caped the pipe coming from the canister to the EVAP valve (it’s situated on the engine) an also blocked the pipe to the valve (so there would be no vacuum leak).
Next morning when i started the car I also logged the rpm vs canister purge valve opening. It did not open at least for as long as i logged it (until the car died)I’ve also tested the valve (bidirectional testing with the laptop), blowing air in through one side, and it would only pass through when the valve would be opened.
What i was thinking now:
Knock sensor… maybe (but still would not explain the difference in running with more/less fuel in tank)
Reasoning: when the engine is cold it’s dry (until the oil comes up) ..so it’s much noisier, so maybe the ecu is retarding the engine to much.. so it’s not able to keep running.
With starting fluid it’s running richer .. so less chance of pinging… so it’s not going to die.Now.. i should unplug the sensor and see how it goes.. just that the sensor is only accessible from underneath – it’s somewhere above the starter motor.
[quote=”umbergbr” post=104819]I had a similar issue with a truck I used to have. It would act strangely after a fill up or on cold starts. It ended up being a bad fuel pump module. Nothing wrong with the pressure it had to do with the evap system. Somehow raw fuel was getting drawn up into the system and when the solenoid would open to dump what was supposed to be fumes it was dumping fuel into the intake system causing it to sputter and die. Once the engine got hot it would vaporize the fuel prior to it entering the cylinders.
[/quote]I already thought about that.
The evaporative system is separate with a charcoal canister next to the tank and line to the valve, it’s not connected to the fuel pump at least in my car.
So one evening I unplugged and caped the pipe coming from the canister to the EVAP valve (it’s situated on the engine) an also blocked the pipe to the valve (so there would be no vacuum leak).
Next morning when i started the car I also logged the rpm vs canister purge valve opening. It did not open at least for as long as i logged it (until the car died)I’ve also tested the valve (bidirectional testing with the laptop), blowing air in through one side, and it would only pass through when the valve would be opened.
What i was thinking now:
Knock sensor… maybe (but still would not explain the difference in running with more/less fuel in tank)
Reasoning: when the engine is cold it’s dry (until the oil comes up) ..so it’s much noisier, so maybe the ecu is retarding the engine to much.. so it’s not able to keep running.
With starting fluid it’s running richer .. so less chance of pinging… so it’s not going to die.Now.. i should unplug the sensor and see how it goes.. just that the sensor is only accessible from underneath – it’s somewhere above the starter motor.
