Uber LAME... Z4 35i limp mode while commuting

[nicknaz]

Guys, I can't believe it but my 35i went into limp mode during my COMMUTE

I was driving in sport+, engine speed at 3000 rpm and over in slow moving traffic for about 35 minutes. When the traffic cleared up, I hit the gas and was greeted with absolutely no turbo boost.

My suspicion is that I heat soaked the car into limp mode through a combination of sustained moderate engine speed / light boost and very little airflow to the radiators. Car was back to normal after sitting and cooling down in the garage.

EDIT: 54F outside

UPDATE: radiator assembly was changed.. will see if that issue in traffic comes up again

[jparnes1]

Gotta believe its an issue with your car as this is not even remotely a common problem.

[nicknaz]

yea this new one could be an issue. I'll report back if it is.

EDIT: jparnes1, anything in particular you recommend that I check

[Asbjorn]

You forgot to report altitude and ambient temperature.

I never managed to limb mine, but I have to admit I would never keep revs at 3000rpm while in slow moving traffic for +30mins. I can accept arriving home that 1 minute later haha.

Sport+ is great for getting a little sideways while negotiating turns, but with the manual mode and fast shifting speeds available with the DCT there is really no need for keeping the revs at +3000rpm all the time.

And while on the topic I would recommend that you cool down the N54 engine by cruising at 70-90kmh (45-55mph) in 7th gear for a few minutes instead of just turning off the engine. It is more effective and better for the turbos in case you are planning on keeping the car.

[nicknaz]

I'm in San Diego. Its pretty much sea level and it was 54F out last night

@Ashborn, Yes I do that cool down but I think its more for paranoia since the N54 has an electric water pump that can be turned on automatically by the car even if the engine is turned off.

UPDATE EDIT: I took the car in and the radiator fan assembly was replaced. The fan was turned on last night after the power loss happened, but apparently it was malfunctioning.

[tranquility]

What is 260F in terms of where the needle was pointing? Way past 1/2way?

[Asbjorn]

That would be a little bit past the middle, and about the highest I have ever seen mine at btw.

[Crazykoh]

Originally Posted by Asbjorn

That would be a little bit past the middle, and about the highest I have ever seen mine at btw.

260 F is about 127 C. Just in case the metric gauge isn't set up the same as the imperial.

[tranquility]

Hmm, that's w/i the normal range, isn't it? I mean, I had it go that high b4 w/o prbs, but usually I'm a bit under the middle.

[nicknaz]

Yea, correct, 260F is one tick mark to the right of center. The US cars have 250F as the 6'o clock position, and when my car is cruising it is at 240F or just under the middle.

My understanding is that one trigger for engine power reduction is 270F oil temps, and I'm very puzzled that these temps are so easily achieved on the street.

Hopefully there truly is something wrong with my car and the dealer can sort it out otherwise it is going to be a long 28 months trying not to be frustrated with a car that can be push to power reduction conditions so easily.

Makes me wish for good old 7.0L of American Iron, rather than all these finnicky "innovations"

[flpnout]

I pushed mine pretty hard on the track and I've never had any issues with the temperature. Hope you get yours sorted out.

[wdlfbio]

Shoulda got the "is" :

Just screwing with u. I hope it really is as simple as a radiator fan malfunction and not indicative of our usual N54/55 heat soak limping.

[nicknaz]

Originally Posted by flpnout

I pushed mine pretty hard on the track and I've never had any issues with the temperature. Hope you get yours sorted out.

You sure you're pushing hard then

J/K

@wdlfbio... Unfortunately the z435is and z435i have the same cooling parts. I personally think this is the n54 limp mode coming through since our cars don't have the higher wattage cooling fan and auxiliary radiator like the 335is and 1M.

I'm planning to keep working with the dealer to rule out defective parts though, just in case.

[jparnes1]

Originally Posted by Asbjorn

You forgot to report altitude and ambient temperature.

I never managed to limb mine, but I have to admit I would never keep revs at 3000rpm while in slow moving traffic for +30mins. I can accept arriving home that 1 minute later haha.

Sport+ is great for getting a little sideways while negotiating turns, but with the manual mode and fast shifting speeds available with the DCT there is really no need for keeping the revs at +3000rpm all the time.

And while on the topic I would recommend that you cool down the N54 engine by cruising at 70-90kmh (45-55mph) in 7th gear for a few minutes instead of just turning off the engine. It is more effective and better for the turbos in case you are planning on keeping the car.

Have you ever seen the oil temp drop after you try to cool down by running at low rpms? I never have. I even let it idle for a long time (10 minutes) and never saw the needle move. And mind you I have an oil cooler in my m sport. It's a good idea but it just doesn't work in this engine. My suspicion is that BMW eliminated turbo lag by letting the turbos spin all the time. No spool up, no lag. But also making it hard to cool them down. I don't bother anymore.

[wdlfbio]

Originally Posted by nicknaz

@wdlfbio... Unfortunately the z435is and z435i have the same cooling parts. I personally think this is the n54 limp mode coming through since our cars don't have the higher wattage cooling fan and auxiliary radiator like the 335is and 1M.
.

According to BMW, the 35is has added oil and water cooling to compensate for the increased hp and torque over the 35i

[jparnes1]

Originally Posted by wdlfbio

According to BMW, the 35is has added oil and water cooling to compensate for the increased hp and torque over the 35i

Yes, 35is and 35i with the M-Sport package all have oil coolers.

[vasmir]

Originally Posted by jparnes1

Yes, 35is and 35i with the M-Sport package all have oil coolers.

Yeah I was just about to ask nicknaz, does your 35i have the m-sport package?

BMW doesn't do a very good job of advertising this in the m-sport package equipment.

[nicknaz]

Yes my car has the oil cooler in front of the passenger side tire.

It's a 35i with regular sport package.

I could be wrong but I am not seeing the 35is as having a higher wattage cooling fan or auxiliary radiator in front of the driver side tire so I don't see what the extra cooling is.

[cdeslandes]

Originally Posted by nicknaz

Yes my car has the oil cooler in front of the passenger side tire.

It's a 35i with regular sport package.

I could be wrong but I am not seeing the 35is as having a higher wattage cooling fan or auxiliary radiator in front of the driver side tire so I don't see what the extra cooling is.

I have a 35i without the sport package and it too has the oil cooler.

I'm surprised at the temps posted here. It takes spirited driving to get my oil temp to 270F. I usually get 240, even in heavy traffic. Something's wrong with the OP's car.

[nicknaz]

Originally Posted by cdeslandes

I have a 35i without the sport package and it too has the oil cooler.

I'm surprised at the temps posted here. It takes spirited driving to get my oil temp to 270F. I usually get 240, even in heavy traffic. Something's wrong with the OP's car.

The radiator assembly was replaced on my car so that will hopefully fix the issue with limp mode from stop and go traffic.

The oil temp was 240F when the limp mode happened so it isn't always obvious when the car is reducing power. I only caught it this time because it completely was not boosting.

I think we are saying the same thing that spirited driving raises oil temps (obviously!) my complaint is that 30 min of straight line pulls (not even to triple digit mph) and sustained 3000rpm+ driving for 30 min appears to constitute "spirited driving" for the car, but I define that as "commuting".

So more concretely, what should I ask the dealer to look at? I told them I hit 260F oil temp on the highway and the response is "it's normal". I am inclined to agree and that the car just doesn't have enough cooling gear.

But you guys appear to be saying you can drive how I am describing in your cars and never limp mode or power reduction. So what should I ask them to look at?

[z4z4z4]

Originally Posted by nicknaz

I think we are saying the same thing that spirited driving raises oil temps (obviously!) my complaint is that 30 min of straight line pulls (not even to triple digit mph) and sustained 3000rpm+ driving for 30 min appears to constitute "spirited driving" for the car, but I define that as "commuting".

nickaz, if you sustained 3000 rpm for 30 minutes with a DCT and 19" wheels that is equal to 90 mph covering 45 miles in 7th gear and is clearly spirited driving. IF you were sustaining that in any other gear then I have no advice. That's 15 laps on a 3 mile per lap road course with a 90 mph average lap speed. Spirited. Should we be able to do that without reaching critical engine temperatures? I'd like to think so also. I hope you're not a quart+ low on oil, or low water/coolant level or pressure.

[nicknaz]

http://www.e90post.com/forums/showthread.php?t=461200

I found a really relevant thread over on the E90 forums

This poster has a nice post of oil temps and engine speeds with the stock oil cooler and after going with the aftermarket parts.

That OPs "oil temps after 6 minutes of spirited driving" are very close to what I am seeing

Seems like my car really is a normal N54 car, which is unfortunate because it suggests the fix is to go aftermarket (which I'm not willing to do for warranty/hassle reasons).