[kierownik]

Hey guys.
My 2016 320i with b48 and 50k miles once again treated me to a brand new issue.
Drove 60 miles to the beach today. No problems, the car had power and ran butter smooth.
Parked up. And went to enjoy some sunshine with wife and kids.
Came back to my car, started it, turned the ac max on and started rolling through the car park. First issue was the AC. It suddenly stopped cooling the interior. The fans kept running but it wasn't properly cold. I turned the ac off and on again and it eventually started to cool the interior.
Once I got out of the car park I noticed that the car is lacking power. On setoff in 1st it had good acceleration but once I shifted to 2nd it was almost dead. Pedal to the floor and nothing until it reached 2.5-3k rpm and even then it didn't feel like it had full power.
I managed to get back home but the car had no power all the time. It managed to maintain 70mph but accelerating was just painful.
When I got back home I noticed that the fan radiator fan is on full speed. I also noticed that all the way back home the oil temp was slightly lower than it normally would be under such conditions.
Anyone have any idea what could be the issue?
Thanks.


Edit: started the engine just now after about 2hrs from returning home and.... Check engine light is on. Wasn't before. Also the fan instantly kicked in full speed.
I won't vr able te get the codes read until tomorrow morning. But the onboard computer doesn't show anything at all.

[danb1979]

Originally Posted by kierownik

Hey guys.
My 2016 320i with b48 and 50k miles once again treated me to a brand new issue.
Drove 60 miles to the beach today. No problems, the car had power and ran butter smooth.
Parked up. And went to enjoy some sunshine with wife and kids.
Came back to my car, started it, turned the ac max on and started rolling through the car park. First issue was the AC. It suddenly stopped cooling the interior. The fans kept running but it wasn't properly cold. I turned the ac off and on again and it eventually started to cool the interior.
Once I got out of the car park I noticed that the car is lacking power. On setoff in 1st it had good acceleration but once I shifted to 2nd it was almost dead. Pedal to the floor and nothing until it reached 2.5-3k rpm and even then it didn't feel like it had full power.
I managed to get back home but the car had no power all the time. It managed to maintain 70mph but accelerating was just painful.
When I got back home I noticed that the fan radiator fan is on full speed. I also noticed that all the way back home the oil temp was slightly lower than it normally would be under such conditions.
Anyone have any idea what could be the issue?
Thanks.


Edit: started the engine just now after about 2hrs from returning home and.... Check engine light is on. Wasn't before. Also the fan instantly kicked in full speed.
I won't vr able te get the codes read until tomorrow morning. But the onboard computer doesn't show anything at all.

Yup; time to get the codes read

No point in guessing until you've done that to be fair; it literally could be all sorts

Sounds like it could be a fuelling issue maybe, or a cam/crank sensor issues, more so when its hot?

See what the codes say & go from there

Fingers crossed it's nothing major

[kierownik]

Originally Posted by danb1979

Yup; time to get the codes read

No point in guessing until you've done that to be fair; it literally could be all sorts

Sounds like it could be a fuelling issue maybe, or a cam/crank sensor issues, more so when its hot?

See what the codes say & go from there

Fingers crossed it's nothing major

Managed to get them read now.... Here's what we found....
Deleting the fault codes brings the powder back and turns the fan off for couple of minutes before the code kicks back in.
If it's a faulty sensor I can change it myself but I'm looking at all the hoses and I can't find the thing.

[kierownik]

Is this the one?

[bishbosh]

Yes that looks correct.

I had the coolant temp sensor play up on my old 320d, but that exhibited random power surges!

Check the hidden menu and see if the coolant temperature fluctuates. When mine went wrong it would read something daft like minus 40!

[kierownik]

Originally Posted by bishbosh

Yes that looks correct.

I had the coolant temp sensor play up on my old 320d, but that exhibited random power surges!

Check the hidden menu and see if the coolant temperature fluctuates. When mine went wrong it would read something daft like minus 40!

When I checked it earlier it was actually showing what seemed to be correct'ish temp. It was at 99c but the fan was on full blast. Very weird. I'll test it tomorrow again.
The other thing that bothers me is that I had a quick look under the bonnet and it looks like to access the sensor I would need to remove the intake manifold. That's a massive job and might be to much for me actually. Super annoying.

[bishbosh]

What's the coolant level like?

[kierownik]

Originally Posted by bishbosh

What's the coolant level like?

It's where it should be.

[kierownik]

I took the car for a quick test drive this morning with everything being cold. Opened the hidden menu to keep an eye on the coolant temp. Here's what happened. When I set off the coolant temp was just 20C. It kept rising as normal until it got to almost 70C. At this point the car lost power and the temp dropped to -38C within couple of seconds and the car became extremely rapid, like it got a massive power boost. Very weird. After about 10-15 seconds the temp went back up to about 65C and it kept going up and down by about 5C. It never exceeded 70C and just kept fluctuating.

So... it looks like it is the sensor that needs replacing.
I'm also waiting for an endoscope camera to arrive from amazon today so I can inspect all the wires under the intake manifold to see if there's any damage to them before I start to take the thing apart.

There's another question... I found that there are two sensors. One under the intake manifold and one at the front of the engine. How do I check which one is gone?

Edit..
OK I think it's the one under the intake manifold. The reason why is because I unplugged the one at the front of the engine but the coolant temp kept fluctuating and it made no difference.

[kierownik]

All the wires are intact. Checked them with the endoscope camera today. So it looks like I'll have no choice but to take the intake manifold out.

I was thinking about removing the ecu and the bracket it's sitting in but I don't think it will make enough room to get the sensor changed easily.

[bishbosh]

Originally Posted by kierownik

I took the car for a quick test drive this morning with everything being cold. Opened the hidden menu to keep an eye on the coolant temp. Here's what happened. When I set off the coolant temp was just 20C. It kept rising as normal until it got to almost 70C. At this point the car lost power and the temp dropped to -38C within couple of seconds and the car became extremely rapid, like it got a massive power boost. Very weird. After about 10-15 seconds the temp went back up to about 65C and it kept going up and down by about 5C. It never exceeded 70C and just kept fluctuating.

So... it looks like it is the sensor that needs replacing.
I'm also waiting for an endoscope camera to arrive from amazon today so I can inspect all the wires under the intake manifold to see if there's any damage to them before I start to take the thing apart.

There's another question... I found that there are two sensors. One under the intake manifold and one at the front of the engine. How do I check which one is gone?

Edit..
OK I think it's the one under the intake manifold. The reason why is because I unplugged the one at the front of the engine but the coolant temp kept fluctuating and it made no difference.

Yes I see there's a temp sensor at the front but just for the cylinder head must be unique to the petrols as the diesels don't have that, just one sensor for the coolant temp. Annoying if you have to remove the inlet manifold though.

Make sure whoever changes the sensor gets a genuine one. I had a garage change mine and it failed after 6 months. I replaced it myself with genuine and it was fine ever since.

[kierownik]

Originally Posted by bishbosh

Yes I see there's a temp sensor at the front but just for the cylinder head must be unique to the petrols as the diesels don't have that, just one sensor for the coolant temp. Annoying if you have to remove the inlet manifold though.

Make sure whoever changes the sensor gets a genuine one. I had a garage change mine and it failed after 6 months. I replaced it myself with genuine and it was fine ever since.

I'm going to do it myself. I know it's going to be a pain to get it done but it is what it is. Also going to biu a genuine one. I'll be ringing my local BMW dealer at 8am tomorrow and fingers crossed they'll have one in stock. I need this car fixed by Tuesday to be able to go to work.

[TurboWeasel]

One thing I would say in general about petrol engines is to not floor it if the engine isn't pulling properly with normal pedal pressure. If you don't carry Bimmerlink and dongle with you in the car at all times (and I highly recommend you do!), either get it recovered or nurse it back home gently.

Originally Posted by bishbosh

Make sure whoever changes the sensor gets a genuine one. I had a garage change mine and it failed after 6 months. I replaced it myself with genuine and it was fine ever since.

100%. Always genuine with electrical stuff. Pattern sensors are just poorly calibrated and poorly made garbage.

[kierownik]

Originally Posted by TurboWeasel

One thing I would say in general about petrol engines is to not floor it if the engine isn't pulling properly with normal pedal pressure. If you don't carry Bimmerlink and dongle with you in the car at all times (and I highly recommend you do!), either get it recovered or nurse it back home gently.



100%. Always genuine with electrical stuff. Pattern sensors are just poorly calibrated and poorly made garbage.

I made it back home, it was a struggle but it made it. I don't know if I caused any damage but hopefully not. The cooling fan was on full blast and the temps were definitely lower than they normally would be so I don't think anything has gone wrong.

Like you said It might be a good idea to get some diagnostic dongle for the future.

Also when it comes to parts like this I would only buy genuine anyway.

And here's the current situation....

[TurboWeasel]

Getting stuck in, I like it

Yeah you should be OK. I suspect the ECU might have limited the throttle opening, or valvetronic openings, what ever it uses - as a failsafe.

A new sensor should see you right. Annoying and typical they put it in such a stupid place!

[kierownik]

Thanks. I just finished and It looks like it is fixed. Taking off the intake manifold wasn't as bad as I thought it would be.
And we have no more codes after a test drive and bringing everything to operating temps.

[TurboWeasel]

Calling that fixed. Just think how much you've saved over a main dealer charging you handsomely for screwing it up.

[bishbosh]

Good job