[DGM M5C]

Well this was a new one. About 30 mins into my 35 min commute home and my redline dropped to 4000. I’ve had BMWs go into limp mode before, but there’s usually an associated message. Nothing here and super weird. I only noticed because it was sluggish accelerating during stop and go traffic. Got it in the garage, shut it off and restarted. Redline back to normal. Anyone else have this before?

[DGM M5C]

Just did it again with the family in the car on our way back from a ceremony. It’s not super hot outside. Not sure what’s going on. 🤬

[ResIpsaLoquitur]

Originally Posted by DGM M5C

Well this was a new one. About 30 mins into my 35 min commute home and my redline dropped to 4000. I’ve had BMWs go into limp mode before, but there’s usually an associated message. Nothing here and super weird. I only noticed because it was sluggish accelerating during stop and go traffic. Got it in the garage, shut it off and restarted. Redline back to normal. Anyone else have this before?

Not sure what’s going on, but for what it’s worth, whenever I had a situation where the car truly went to limp mode (in my case, due to HPFP failure) I wasn’t able to even get close to 4000.

What happens when you try to go WOT? Does it go to 4000 and not further, but still accelerate sluggishly?

[DGM M5C]

Originally Posted by ResIpsaLoquitur

Not sure what’s going on, but for what it’s worth, whenever I had a situation where the car truly went to limp mode (in my case, due to HPFP failure) I wasn’t able to even get close to 4000.

What happens when you try to go WOT? Does it go to 4000 and not further, but still accelerate sluggishly?

Wasn’t willing to do that since this is my 2nd motor and I don’t want to wait another 2 months for a new one if this one decides to call it quits too. 😂

It was actually gutless under 4k and kind of reminded me of Eco mode in my previous 550.

[LouK]

When my 18 had a rock damage one of the radiators (not the main engine one), it didn't throw any codes but would essentially not build boost due to the intake temps. The redline did not change on mine, but they could have changed it for the LCI. Just a thought.

[ResIpsaLoquitur]

Originally Posted by DGM M5C

Wasn’t willing to do that since this is my 2nd motor and I don’t want to wait another 2 months for a new one if this one decides to call it quits too. 😂

It was actually gutless under 4k and kind of reminded me of Eco mode in my previous 550.

Damn, that’s right. I totally forgot about your motor replacement until you mentioned it here. Given that, I would get this into service immediately. This might have been less of a concern for someone else, but due to the history, I’d want this dealership diagnosed ASAP. Even if the car isn’t throwing codes now, it’s possible there will be stored codes related to the issue.

[Justao]

Did you check the coolant temperature when this happened?

[AHall]

Did anyone determine the cause of your original issue? Maybe replacing the engine did not address it.

[DGM M5C]

Originally Posted by Justao

Did you check the coolant temperature when this happened?

Smack dab in the middle of the gauge, just like normal.

Originally Posted by AHall

Did anyone determine the cause of your original issue? Maybe replacing the engine did not address it.

Haven’t heard what happened with the original. I’ve got 12k on the new engine, so I don’t think it’s related and would like to think it would have reappeared before this since the original issue happened at 700 miles.

I actually wonder if it was a fuel pump issue starting to rear it’s ugly head since I was less than a quarter tank of gas at the time. Not sure if it would reduce RPMs in that scenario to not allow for high RPM usage and avoid cavitating the pump if it is starting to go. Filled it up last night, so I’ll see what happens today.

[pmsteinm]

I would have thought BMW finally figured out how to make a good HPFP after 16 years. My wife's N54 needed 2 before they finally had an improved one that lasted at least 100k miles until we sold the car. I wonder if other brands with DI engines have problems with their high pressure pumps too.

Based on the comments on this forum I'm consistent about never letting my car get below 1/4 tank to protect the low pressure pump. That still gives me less frequent fill-ups than my old car since the mileage is better and the tank is bigger.

[Patton250]

I want to hear how this ends. Sorry this happened.

[micvite]

Originally Posted by DGM M5C

Well this was a new one. About 30 mins into my 35 min commute home and my redline dropped to 4000. I’ve had BMWs go into limp mode before, but there’s usually an associated message. Nothing here and super weird. I only noticed because it was sluggish accelerating during stop and go traffic. Got it in the garage, shut it off and restarted. Redline back to normal. Anyone else have this before?

Had this happen on my rental m5 in Germany, had 2 issues after scanning codes. Intake temps like someone else mentioned and injector 7 shut off which was probably leaky coolant tank since 7 is right under it... sometimes it gave a warning ?drivetrain malfunction continued driving possible, sometimes it didn't. But it would just stop at 4k after some WOT driging and after some time the redline would fix itself again maybe 20-30 sec later.

[DGM M5C]

Originally Posted by micvite

Had this happen on my rental m5 in Germany, had 2 issues after scanning codes. Intake temps like someone else mentioned and injector 7 shut off which was probably leaky coolant tank since 7 is right under it... sometimes it gave a warning ?drivetrain malfunction continued driving possible, sometimes it didn't. But it would just stop at 4k after some WOT driging and after some time the redline would fix itself again maybe 20-30 sec later.

I was worried it might be a expansion tank problem too and looked at it, but only saw a couple white spots on the side. Not saying it isn't related, but I sure hope not. Anyone who recently had their tank replaced, what was the turn around time?

[pbonsalb]

You can get a scan tool sophisticated enough to see shadow codes for $200. Well worth the investment if you want to know more than the idrive screen telling you there is a malfunction and people giving you a list of malfunctions they have experienced. Maybe you do have a bad HPFP or a failing injector from a leaking coolant tank or maybe both or maybe neither and it is something else.

[DGM M5C]

You can get a scan tool sophisticated enough to see shadow codes for $200. Well worth the investment if you want to know more than the idrive screen telling you there is a malfunction and people giving you a list of malfunctions they have experienced. Maybe you do have a bad HPFP or a failing injector from a leaking coolant tank or maybe both or maybe neither and it is something else.

I can't believe I asked a car forum if anyone had experienced a very specific scenario of redline getting reduced to 4k with no service messages. What was I thinking? GFY

[pbonsalb]

Someone is frustrated ….

[DGM M5C]

Originally Posted by Patton250

I want to hear how this ends. Sorry this happened.

Just got done with the dealer. No stored codes or anything. They went through the logs and looked at the specific times the events occurred and they can see where it happened, but nothing that caught their eye.

They asked if I drive it hard and I said yup, not a problem there. They said that’s good, the car needs to be driven hard. 😂

Originally Posted by AHall

Did anyone determine the cause of your original issue? Maybe replacing the engine did not address it.

Asked the service manager today and he said they didn’t ever hear anything.

[ResIpsaLoquitur]

Not bad news all things considered. Hopefully (and sounds like) just a one off. Wishing you good drives ahead!

[Jakerx]

Originally Posted by DGM M5C

I can't believe I asked a car forum if anyone had experienced a very specific scenario of redline getting reduced to 4k with no service messages. What was I thinking? GFY

Not the best attitude to have when asking for help on a forum. The person who posted above you was merely suggesting you buy a scan tool to give you better data. I understand you’re frustrated but no need to be a dick.

[Da_BatMann_]

Did you ever figure this one out?

I have a similar issue on my m8, been posting about it for a few months now.

Just like you, Dealer couldn't find anything wrong with mine either.

Have you discovered anything since?

[micvite]

Originally Posted by Da_BatMann_

Did you ever figure this one out?

I have a similar issue on my m8, been posting about it for a few months now.

Just like you, Dealer couldn't find anything wrong with mine either.

Have you discovered anything since?

Your issue is most likely intercooler coolant is low/leaking and causing your IATs or charfed air temps to go through the roof. Codes don't stick around after car is shut off so you have to scan it after it messes up before shutting car off.

[jnotrom711]

I had this happen twice on my m5c, out was vanos solenoids. Ill double check but I know it was something to do with vanos system, not a major issue, and was covered under warranty, but even if it hadn't been covered, I dont remember it being too expensive.

Would go into like 1/2 limp mode, no check engine lights, but would drop the redline like that.

the replaced one, then the other months later. no issues since replacements.