Alfa Romeo Forum banner
1 - 13 of 13 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter · #1 ·
Greetings from Finland!

So, as I was driving at the highway to work this morning, my 2011 Giulietta 1.4 MA lost nearly all the power output from the engine just as I was exiting the highway going up a steep curved ramp. At the same time, the car computer informed me that ASR, VDC, ABS, power steering, steering corrector, start/stop and hillholder were disabled. The engine remained on but juddered slightly. I shut down the engine and started it again, resulting in a normal operation with only "Check engine" message displaying in the info screen and the check engine light lit next to the rev dial.

So, I get going and go the rest of the way to my workplace during which the same happens twice; engine power output loss with judder and the myriad of disabled electrical fancies. I parked the car and read the fault codes with the handy Torque app and got: P0301 - Powertrain (Cylinder 1 misfire detected) and P0101 - Powertrain (Mass of Volume Air Flow Circuit Range/Performance Problem). I decided to leave the car at place and come back at lunch break to see if the faults have disappeared. They had not and I decided to clear them with the app. This was succesful and I drove it around for 10 km or so and nothing out of the ordinary happened.

The same sort of thing happened last winter, where upon starting, the engine juddered and seemed to run only on three cylinders. The check engine light lit up but cleared itself away when stopping and starting the engine again. The electric system anomalies didn't occur.

*At the time, the prevailing temperature had dropped from yesterday's -11 °C to -21 °C
*Fuel tank was mostly empty with the fuel light on (when I drove it around for the 10 km at lunch break, I also topped the tank with 53 l displaying at the gas station pump)
*Service coming up in 8000 km (~5 kmiles)
*Mileage was 80 002 km (54+ kmiles) at the highway incident
*Car is equipped with an electrical engine heater and was plugged in for 1.5 h prior to leaving
*I had the engine heater branched to include a cabin heater last week

I thought nothing of it since the earlier occurance and the fact that the temperature dropped so abruptly. Might even have condensation in the tank. Other threads reported checking the battery leads especially regarding the electric system going disabled and so I did: seemed normal. Asking some thoughts on this here since I don't mind getting stranded on the road but if this happens to the missus, it might not go so well :paranoid:
 

·
Registered
Joined
·
8,786 Posts

·
Registered
Joined
·
4,932 Posts
In this instance, I don't think it is multiair unit failure. Could be a coil or an engine management earth.
 

·
Registered
Joined
·
3 Posts
Discussion Starter · #5 ·
Oil was changed at 65 000 km and all service done at Alfa dealer. Disheartening to hear it might be the MA unit since it seems to lead to an expensive replacement.

The car was fine when I drove it off from work. I'll see what happens in a few days and might go in for an early service.

Have loved the car anyhow, and while it certainly starts at very cold temperatures, not all parts in it are built for arctic weather (the manual gearbox gets rather stiff at -30 °C or below). Fingers crossed that it was only the sudden temperature drop that got the lady a bit under the weather.
 

·
Registered
Joined
·
3 Posts
Discussion Starter · #7 ·
Hello!

It ended up being the oil segregator (pt.no 55219081, and associated O-ring 50046246 or the newer 50051319 ).

Normal operation of the segregator is to draw the air from the crankcase, seperate the oil from the oil-air mixture, and return the cleaned air to the intake manifold to be used again in the cylinder.

For somewhat similar operation, see:

http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0900c152/80/06/1f/8e/large/0900c15280061f8e.gif

The accumulated oil gunk/water condensation in the segregator, in conjunction with the freezing weather prevented the one-way valves inside the segregator from working. What happened, according to my theory (and I would, in no way, describe myself as a professional in knowing how most of the parts in the car engine bay work):


  • During the highway cruising, the valve had frozen into a fixed position as a result of the low temperature air flow (the oil segregator is located atop of the engine, covered only by the plastic engine cover which does not really help in combating the horizontal air flow coming from the trilobe)
  • Upon downshifting from highway speeds to the exit ramp, the crankcase pressure increased due to increased RPM in the engine
  • At least one of the valves in the oil segregator failed to move to provide capacity to the increased air flow rate
  • Some of the pressure relieved through the oil dipstick pipe and splashed a minor amount of oil on the engine
  • The ECU recognized the increase in RPM but didn't recognize an increase in air manifold pressure (the MAF fault)
  • The MA unit supplied an incorrect air/fuel mixture to the cylinder because the air entering the turbo was not within parameters
  • Misfire in one cylinder led the ECU to shut down the engine
  • The car disabled all of the management systems as a precaution because it did not know what had caused the MAF to report the odd value

After this episode, and having stopped the car, the latent heat from the engine thawed the oil segregator enough to allow normal operation. Also, clearing the ECU codes did not reintroduce them.

After I worked out it was the oil segregator, I pondered around cleaning the oil segregator, but in the end decided it was far less fuss to order a new one for 50 € and deliver the old one to oil waste disposal. Changing the segregator is relatively easy, just the take the engine cover off, disconnect the two (or three) hoses going to the segregator (might need specialized tool for the clamps in the hoses) and undo the three bolts the whole thing is attached to the top of the engine block. Take the old segregator out, and do the installation for the new one backwards with the aforementioned process. The O-ring between the segregator and engine block I mentioned is not necessary to replace, but in my case was brittled and seeped oil slightly through (costs about 7 €) and was easy to chance with the segregator.

Hope this helps you, or someone else.

-zS
 

·
Registered
Joined
·
47 Posts
Thanks. I haven't seen the any sign of oil bursting from the dipstick hole, but there is some leak around the vacuum pump near the segregator. I will check the segregator just in case. Congrats on solving it yourself.
 

·
Registered
Joined
·
300 Posts
Hello!

It ended up being the oil segregator (pt.no 55219081, and associated O-ring 50046246 or the newer 50051319 ).

Normal operation of the segregator is to draw the air from the crankcase, seperate the oil from the oil-air mixture, and return the cleaned air to the intake manifold to be used again in the cylinder.

For somewhat similar operation, see:

http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0900c152/80/06/1f/8e/large/0900c15280061f8e.gif

The accumulated oil gunk/water condensation in the segregator, in conjunction with the freezing weather prevented the one-way valves inside the segregator from working. What happened, according to my theory (and I would, in no way, describe myself as a professional in knowing how most of the parts in the car engine bay work):


  • During the highway cruising, the valve had frozen into a fixed position as a result of the low temperature air flow (the oil segregator is located atop of the engine, covered only by the plastic engine cover which does not really help in combating the horizontal air flow coming from the trilobe)
  • Upon downshifting from highway speeds to the exit ramp, the crankcase pressure increased due to increased RPM in the engine
  • At least one of the valves in the oil segregator failed to move to provide capacity to the increased air flow rate
  • Some of the pressure relieved through the oil dipstick pipe and splashed a minor amount of oil on the engine
  • The ECU recognized the increase in RPM but didn't recognize an increase in air manifold pressure (the MAF fault)
  • The MA unit supplied an incorrect air/fuel mixture to the cylinder because the air entering the turbo was not within parameters
  • Misfire in one cylinder led the ECU to shut down the engine
  • The car disabled all of the management systems as a precaution because it did not know what had caused the MAF to report the odd value

After this episode, and having stopped the car, the latent heat from the engine thawed the oil segregator enough to allow normal operation. Also, clearing the ECU codes did not reintroduce them.

After I worked out it was the oil segregator, I pondered around cleaning the oil segregator, but in the end decided it was far less fuss to order a new one for 50 € and deliver the old one to oil waste disposal. Changing the segregator is relatively easy, just the take the engine cover off, disconnect the two (or three) hoses going to the segregator (might need specialized tool for the clamps in the hoses) and undo the three bolts the whole thing is attached to the top of the engine block. Take the old segregator out, and do the installation for the new one backwards with the aforementioned process. The O-ring between the segregator and engine block I mentioned is not necessary to replace, but in my case was brittled and seeped oil slightly through (costs about 7 €) and was easy to chance with the segregator.

Hope this helps you, or someone else.

-zS
Thanks for updating with the fix!
 

·
Registered
Joined
·
4 Posts
Hello!

It ended up being the oil segregator (pt.no 55219081, and associated O-ring 50046246 or the newer 50051319 ).

Normal operation of the segregator is to draw the air from the crankcase, seperate the oil from the oil-air mixture, and return the cleaned air to the intake manifold to be used again in the cylinder.

For somewhat similar operation, see:

http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0900c152/80/06/1f/8e/large/0900c15280061f8e.gif

The accumulated oil gunk/water condensation in the segregator, in conjunction with the freezing weather prevented the one-way valves inside the segregator from working. What happened, according to my theory (and I would, in no way, describe myself as a professional in knowing how most of the parts in the car engine bay work):


  • During the highway cruising, the valve had frozen into a fixed position as a result of the low temperature air flow (the oil segregator is located atop of the engine, covered only by the plastic engine cover which does not really help in combating the horizontal air flow coming from the trilobe)
  • Upon downshifting from highway speeds to the exit ramp, the crankcase pressure increased due to increased RPM in the engine
  • At least one of the valves in the oil segregator failed to move to provide capacity to the increased air flow rate
  • Some of the pressure relieved through the oil dipstick pipe and splashed a minor amount of oil on the engine
  • The ECU recognized the increase in RPM but didn't recognize an increase in air manifold pressure (the MAF fault)
  • The MA unit supplied an incorrect air/fuel mixture to the cylinder because the air entering the turbo was not within parameters
  • Misfire in one cylinder led the ECU to shut down the engine
  • The car disabled all of the management systems as a precaution because it did not know what had caused the MAF to report the odd value

After this episode, and having stopped the car, the latent heat from the engine thawed the oil segregator enough to allow normal operation. Also, clearing the ECU codes did not reintroduce them.

After I worked out it was the oil segregator, I pondered around cleaning the oil segregator, but in the end decided it was far less fuss to order a new one for 50 € and deliver the old one to oil waste disposal. Changing the segregator is relatively easy, just the take the engine cover off, disconnect the two (or three) hoses going to the segregator (might need specialized tool for the clamps in the hoses) and undo the three bolts the whole thing is attached to the top of the engine block. Take the old segregator out, and do the installation for the new one backwards with the aforementioned process. The O-ring between the segregator and engine block I mentioned is not necessary to replace, but in my case was brittled and seeped oil slightly through (costs about 7 €) and was easy to chance with the segregator.

Hope this helps you, or someone else.

-zS
I have had the same problem myself (N of Sweden) in the cold. I am about to clean the segregator this weekend. I´ve heard of others too with a G that does this on a regular basis every year and since they started do this never had any limp modes issues.
 

·
Registered
Joined
·
300 Posts
I have had the same problem myself (N of Sweden) in the cold. I am about to clean the segregator this weekend. I´ve heard of others too with a G that does this on a regular basis every year and since they started do this never had any limp modes issues.
Please update with your findings, would be very interesting to know how dirty it is.
 
1 - 13 of 13 Posts
Top