123d Bi turbo boost disabled.
Discussion
Hi , i've had an ongoing issue with the boost pressure on my D3 Alpina Bi Turbo and last week i managed to get the car scanned with ISTA+ and the following was identified:
Code 4CA0 Oil pressure plauseability. This showed as not being active but when we tried to reset and clear the fault it came back on again but still wasn't active. As a precaution i will be changing the switch and probably fitting a direct eart connection just incase that is the cause of the spurious code returning
With ISTA we also checked the Charge pressure control test and the first controller functioned correctly and the exhaust note changed as and when the waste gate operated on the big turbo however the second controller just stayed at 25% and did not cycle the waste gate on the smaller turbo. This should cycle also but it doesn't.
I've checked the following:
All electrical connections
There is vacuum availabe at the pressure control solenoid and the waste gate actuator moves if a vac pump is connected. Changing the pressure control solenoid made no difference. the coil resistance was 14 ohms.
The car runs fine but lacks bottom end grunt and many thanks to Andy who did a test drive to compare to his own Alpina and confirmed the lack of grunt.
My question is does the 4CA0 fault code cause the turbo pressue to disable the small turbo pressure control system.
Please only reply if you have some in depth knowledge of how the DME functions as i would like to ensure any future person with the same fault can get a reasonable chance of sorting out their car also.
Many thanks
RossCo
Code 4CA0 Oil pressure plauseability. This showed as not being active but when we tried to reset and clear the fault it came back on again but still wasn't active. As a precaution i will be changing the switch and probably fitting a direct eart connection just incase that is the cause of the spurious code returning
With ISTA we also checked the Charge pressure control test and the first controller functioned correctly and the exhaust note changed as and when the waste gate operated on the big turbo however the second controller just stayed at 25% and did not cycle the waste gate on the smaller turbo. This should cycle also but it doesn't.
I've checked the following:
All electrical connections
There is vacuum availabe at the pressure control solenoid and the waste gate actuator moves if a vac pump is connected. Changing the pressure control solenoid made no difference. the coil resistance was 14 ohms.
The car runs fine but lacks bottom end grunt and many thanks to Andy who did a test drive to compare to his own Alpina and confirmed the lack of grunt.
My question is does the 4CA0 fault code cause the turbo pressue to disable the small turbo pressure control system.
Please only reply if you have some in depth knowledge of how the DME functions as i would like to ensure any future person with the same fault can get a reasonable chance of sorting out their car also.
Many thanks
RossCo
On this engine, people regularly point to the pressure converter valves, with one of them going bad. But I think you've tested that (pressure control solenoid)? Some light reading here: https://www.babybmw.net/forum/viewtopic.php?t=1315...
Then there's the connection pipe between the two turbos that was leaking in this example: https://www.babybmw.net/forum/viewtopic.php?f=63&a...
The turbos look like this on these cars:
I doubt the oil pressure warning is related. Not the first time I've heard of problems deleting codes with ISTA mind; I use the older Ediabas for code deletion generally, or Carly.
Then there's the connection pipe between the two turbos that was leaking in this example: https://www.babybmw.net/forum/viewtopic.php?f=63&a...
The turbos look like this on these cars:
I doubt the oil pressure warning is related. Not the first time I've heard of problems deleting codes with ISTA mind; I use the older Ediabas for code deletion generally, or Carly.
BFleming
Many thanks for the useful links and also the photos and comments.
My Alpina is equipped with the earlier twin turbo that has 3 actuator that are vacuum controlled. I've stripped all the pressure control valves off the mounting plate thats a real pig to access and whilst testing the vacuum hose i think i've discovered that the actuator thats connected to the blue vacuum pipework is leaking so i need to get the undertray off and investigate further if its the blue hose leaking or the accuator. .
Changing the oil pressure switch seems to have cleared the 4CA0 code that wouldn't reset that some think can keep coming back due to an earthing issue. This also isn't easy to access and needs a deep 24mm socket.
Update to follow
Thanks
Many thanks for the useful links and also the photos and comments.
My Alpina is equipped with the earlier twin turbo that has 3 actuator that are vacuum controlled. I've stripped all the pressure control valves off the mounting plate thats a real pig to access and whilst testing the vacuum hose i think i've discovered that the actuator thats connected to the blue vacuum pipework is leaking so i need to get the undertray off and investigate further if its the blue hose leaking or the accuator. .
Changing the oil pressure switch seems to have cleared the 4CA0 code that wouldn't reset that some think can keep coming back due to an earthing issue. This also isn't easy to access and needs a deep 24mm socket.
Update to follow
Thanks
Decent, glad you're sort-of sorted.
The other areas for restoration of boost seem to be...
EGR valve sticky (remember the EGR is unlikely to have been recalled, just the cooler, so taking the cover off & re-copper-greasing it while moving it through its movement limits certainly seems to help things)
MAP sensor sooted up - remove, clean with carb cleaner, replace
Inlet manifold gummed up. Bit of a pig to remove, but not impossible. I've seen people leave them soaking in oven cleaner, steam cleaning them, etc etc, but all have said the car runs like new again afterwards
The other areas for restoration of boost seem to be...
EGR valve sticky (remember the EGR is unlikely to have been recalled, just the cooler, so taking the cover off & re-copper-greasing it while moving it through its movement limits certainly seems to help things)
MAP sensor sooted up - remove, clean with carb cleaner, replace
Inlet manifold gummed up. Bit of a pig to remove, but not impossible. I've seen people leave them soaking in oven cleaner, steam cleaning them, etc etc, but all have said the car runs like new again afterwards
Edited by BFleming on Thursday 29th April 15:46
Thanks for the additional tips.
I assume you mean the MAP sensor, that was one of the 1st things i looked at as i've had that before, the EGR and cooler has been removed and next of the list is the removal of the inlet manifold for a full clean and also a swirls flap delete.
I've not had the EGR deleted from the DCM but will do that later when i can find a reasonable place that won't charge me £250 for a 10 min mod and down load. The car does drive a lot better though and i may refit the EGR once the manifold has been cleaned
Thanks
I assume you mean the MAP sensor, that was one of the 1st things i looked at as i've had that before, the EGR and cooler has been removed and next of the list is the removal of the inlet manifold for a full clean and also a swirls flap delete.
I've not had the EGR deleted from the DCM but will do that later when i can find a reasonable place that won't charge me £250 for a 10 min mod and down load. The car does drive a lot better though and i may refit the EGR once the manifold has been cleaned
Thanks
I did indeed mean the MAP sensor - I've corrected that.
On the EGR system, because of where they are on the N47s, they're pretty obvious to see if they're physically missing, so may fail an MOT. Mapping them out is probably better, but I don't know if you need to blank them still - or they stay closed. I think the latter - mapped out & it stays closed. I know Endtuning in Birmingham has mapped out a few - and he's a lot better value than the sum you quoted.
I would be very interested to see the manifold condition when that comes off.
On the EGR system, because of where they are on the N47s, they're pretty obvious to see if they're physically missing, so may fail an MOT. Mapping them out is probably better, but I don't know if you need to blank them still - or they stay closed. I think the latter - mapped out & it stays closed. I know Endtuning in Birmingham has mapped out a few - and he's a lot better value than the sum you quoted.
I would be very interested to see the manifold condition when that comes off.
Many thanks for the update.
I've MOTd numerous diesels and providing it meets the emissions i've not found a test station yet thats failed a diesel of mine for having a DPF or EGR delete.
I have heard a few decent things about endtuning in Brum and i was going to book a visit to get the delete sorted out. Will let you know how it goes with the manifold removal and clean once the weather improves and i can venture out to work on the car some more.
I've MOTd numerous diesels and providing it meets the emissions i've not found a test station yet thats failed a diesel of mine for having a DPF or EGR delete.
I have heard a few decent things about endtuning in Brum and i was going to book a visit to get the delete sorted out. Will let you know how it goes with the manifold removal and clean once the weather improves and i can venture out to work on the car some more.
The N47 isn't the easiest engine to work on...... I'm waiting to se if i get a reply from the guy from Birmingham about the EGR delete but i've also asked him about the small turbo actuator control valve as replacing it didn't change anything.
Will probably start on the inlet strip down next week.
Will probably start on the inlet strip down next week.
Well i did manage to get the small turbo controller to work again after get the car scanned by Auto Dynamics in Newton Abbot. All worked well for a year or so and then the boost from the LP turbo was disabled again. I checked the vacuum to the solenoid, replaced the solenoid but still no boost hence does anyone know what disables the low pressure Turbo pressure controller.
Looks like another trip to Newton Abbot i guess
Looks like another trip to Newton Abbot i guess
Well finally as an update. One of the turbo pressure control circuits was disabled in the ECU and hence an update fixed that.
Next it was leaking hose to the low pressure turbo actuator and then some fault codes with the fuel pressure which cleared after the main filter was replaced and a regen forced on the DPF and all seems good again.
I'm going to do a DPF delete aft the next MOT also but yes you really can chase your arse trying to sort out issues on these car
Next it was leaking hose to the low pressure turbo actuator and then some fault codes with the fuel pressure which cleared after the main filter was replaced and a regen forced on the DPF and all seems good again.
I'm going to do a DPF delete aft the next MOT also but yes you really can chase your arse trying to sort out issues on these car
Rossco196x said:
Well finally as an update. One of the turbo pressure control circuits was disabled in the ECU and hence an update fixed that.
Next it was leaking hose to the low pressure turbo actuator and then some fault codes with the fuel pressure which cleared after the main filter was replaced and a regen forced on the DPF and all seems good again.
I'm going to do a DPF delete aft the next MOT also but yes you really can chase your arse trying to sort out issues on these car
Fair dues - thanks for the update on this.Next it was leaking hose to the low pressure turbo actuator and then some fault codes with the fuel pressure which cleared after the main filter was replaced and a regen forced on the DPF and all seems good again.
I'm going to do a DPF delete aft the next MOT also but yes you really can chase your arse trying to sort out issues on these car
My 525d was sold a few years ago & I miss it, but I did the valve cover gasket, and Mr Muscled the inlet manifold. What a messy job. Next time I'd drop it off to a steam cleaners!
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