640d limited torque after intake removal/refit
Discussion
Hi guys. Hoping for some opinions on what might be causing a strange issue on my 640d
Car had a coolant pipe replaced next to the oil filter housing. It cracked and spewed coolant out while driving, gave a low coolant warning and I pulled over within 2 mins of the warning at the first opportunity. Got recovered home.
I had a mobile mechanic diagnose and replace the pipe. For that he needed to remove the intake manifold. He fixed it no issue and test drove the car. No leaks, no overheating.
While the intake was off he cleaned out a load of gunk from the intake.
It’s been a week since he did the work and the car seems to drive fine other than one issue. In fact it seemed to drive noticeably smoother.
Driving to work an hour each way this week I’ve noticed after about 30-40 minutes of driving the car limits torque and feels a bit flat compared to normal. It definitely doesn’t have full power available. This is backed up by the sports displays which show a max torque figure once it’s limited of about 450nm. I know the displays aren’t necessary accurate, but it backs up what I feel when driving.
The following morning or when leaving work the car seems back to normal, but the fault returns most of the time. Only once in the last three days has it not been limited after driving for a time.
No warning lights have been present on the dash at any time.
Any ideas?
Things I thought could be causing it:
Airflow through the manifold being different because it was cleaned and the ECU is seeing figures different to the learned figures it is expecting.
Coolant temps getting slightly too high and the ECU protecting the engine.
A sensor that’s not properly plugged in and losing connection (though lack of EML makes this unlikely?!)
Air leak on the reinstalled manifold.
Has anybody experienced similar?
The mechanic has said he’ll come back and put his diagnostic kit on it, but I’m not sure what it will show if the car isn’t throwing up a warning light.
Cheers.
Car had a coolant pipe replaced next to the oil filter housing. It cracked and spewed coolant out while driving, gave a low coolant warning and I pulled over within 2 mins of the warning at the first opportunity. Got recovered home.
I had a mobile mechanic diagnose and replace the pipe. For that he needed to remove the intake manifold. He fixed it no issue and test drove the car. No leaks, no overheating.
While the intake was off he cleaned out a load of gunk from the intake.
It’s been a week since he did the work and the car seems to drive fine other than one issue. In fact it seemed to drive noticeably smoother.
Driving to work an hour each way this week I’ve noticed after about 30-40 minutes of driving the car limits torque and feels a bit flat compared to normal. It definitely doesn’t have full power available. This is backed up by the sports displays which show a max torque figure once it’s limited of about 450nm. I know the displays aren’t necessary accurate, but it backs up what I feel when driving.
The following morning or when leaving work the car seems back to normal, but the fault returns most of the time. Only once in the last three days has it not been limited after driving for a time.
No warning lights have been present on the dash at any time.
Any ideas?
Things I thought could be causing it:
Airflow through the manifold being different because it was cleaned and the ECU is seeing figures different to the learned figures it is expecting.
Coolant temps getting slightly too high and the ECU protecting the engine.
A sensor that’s not properly plugged in and losing connection (though lack of EML makes this unlikely?!)
Air leak on the reinstalled manifold.
Has anybody experienced similar?
The mechanic has said he’ll come back and put his diagnostic kit on it, but I’m not sure what it will show if the car isn’t throwing up a warning light.
Cheers.
Edited by HaplessBoyLard on Friday 8th August 12:25
According to Google, that's around 200nm shy of where it should be. You definitely had the sports displays in KW and Nm, and not hp and lbft?
Disturbing the intake manifold and removing crud would not cause a torque shortfall that large. I assume the original gaskets were re-used and not leaking? No air air hissing noises?
Time to get the diagnostic scanner on it, or purchase Bimmerlink and a dongle and do that yourself.
I believe one of the turbos on the biturbo engines has vacuum control? Maybe a vacuum pipe was forgotten off? Look for underboost errors.
Disturbing the intake manifold and removing crud would not cause a torque shortfall that large. I assume the original gaskets were re-used and not leaking? No air air hissing noises?
Time to get the diagnostic scanner on it, or purchase Bimmerlink and a dongle and do that yourself.
I believe one of the turbos on the biturbo engines has vacuum control? Maybe a vacuum pipe was forgotten off? Look for underboost errors.
rottenegg said:
According to Google, that's around 200nm shy of where it should be. You definitely had the sports displays in KW and Nm, and not hp and lbft?
Disturbing the intake manifold and removing crud would not cause a torque shortfall that large. I assume the original gaskets were re-used and not leaking? No air air hissing noises?
Time to get the diagnostic scanner on it, or purchase Bimmerlink and a dongle and do that yourself.
I believe one of the turbos on the biturbo engines has vacuum control? Maybe a vacuum pipe was forgotten off? Look for underboost errors.
New gaskets were used when the manifold went back on. It’s the first time I’ve used this mobile mechanic but he came recommended and seemed very diligent. I don’t have any specific worries about his work. Disturbing the intake manifold and removing crud would not cause a torque shortfall that large. I assume the original gaskets were re-used and not leaking? No air air hissing noises?
Time to get the diagnostic scanner on it, or purchase Bimmerlink and a dongle and do that yourself.
I believe one of the turbos on the biturbo engines has vacuum control? Maybe a vacuum pipe was forgotten off? Look for underboost errors.
It’s definitely in nm and is intermittent. Fine when the car is first driven in the morning, then the fault kicks in after half hour or so. It happened on the way to work this morning, then didn’t on the way home.
When it’s restricted the torque figure goes to the same point on the gauge every time as if it’s definitely being deliberately restricted rather than being erratic.
I’ve got a Bluetooth adapter that should work so I think I’ll get bimmer link and have a look.
Gassing Station | BMW General | Top of Page | What's New | My Stuff