Car Keeps Cutting Off

QuietQuirk · 11-02-2017, 08:01 PM

Hey guys. I'm having an issue where my car (2008 335i) is having something going on with the engine, but the "Service Engine Soon" light is not lit up during normal driving. However during driving at random times the car will jerk, almost like the engine is knocking? Even worse, when I come to a complete stop or very slow roll, the engine WILL CUT OFF, however the electronics and everything else stay on. It basically goes into the exact same mode you can put the car in by pressing the start button without using the brake at the same time to start the car. It's only at this time will the Engine light come on. The car could still be in Drive, and go into this mode. I have to stop, in the middle of traffic, put car into park, and then start the car back up.

This is obviously concerning, and it seems like it's happening more and more. What is going on here?

QuietQuirk · 11-02-2017, 11:39 PM

Nobody?

markv123 · 11-03-2017, 07:01 AM

You may already know but it is handy to have your cars codes read so that it can be used as a starting point.

In terms of your issues, one, of many, possibilities may be that you are suffering an air leak somewhere. These cars are advanced however the same principles for an engine to run still apply. Power, air and fuel.
- Your car starts so you can rule that out.
- Starting your car on cold start will cause fuel and air to be pushed through
- In my experience with cars it sounds like your fuel pump is cutting out (akin to when you're low on fuel) but since it starts up again and keeps running then it may not be that.
- Leaves me with air. You could have a air leak somewhere. Listen for one or perform a smoke test. When the car is warm the idle will not be as high as cold start so it will not force air in.

Now, that's just a little old school thinking on my part and as I said at the start, a code check on these cars will help put you in the right direction first.

Keep us posted.
Hope you get it sorted.

John 070 · 11-03-2017, 07:22 AM

When my car was very new (I am the original owner/2007), the DME was replaced under warranty. There were ZERO codes, car would simply die in the middle of traffic, and I had to limp to the shoulder. After multiple trips to the dealer, it did it while they had it. This enabled them to open a case with BMW and upgrade the DME from a MSD80 to a MSD81. But this was long ago....never did it again, not even once...

p.s. same thing, would never be an issue whatsoever restarting the motor. Which is why the dealership could not do anything without witnessing it. I remember my wife's aunt telling me get rid of that POS, you can't even drive it, what's the point?

just for the heck of it, I googled and see there is a service when you provide the part, so prolly a known issue....

https://www.ebay.com/itm/BMW-MSD80-M...-/262822313971

The_E92_Fan · 11-03-2017, 08:43 AM

an MHD log would help. if either of your fuel pumps are shot or your engine is struggling to breathe, your low and high pressure fuel sensors will reflect, also you can look at STFY %. if you're nearing 34%, your pumps are failing. If your LPFP is not at 80 at idle, and dips below 45 on a pull, you may have an issue

11-02-2017, 08:01 PM	#1
QuietQuirk Enlisted Member 16 Rep 37 Posts Drives: 335i Join Date: Jun 2013 Location: North America iTrader: (0)	Car Keeps Cutting Off Hey guys. I'm having an issue where my car (2008 335i) is having something going on with the engine, but the "Service Engine Soon" light is not lit up during normal driving. However during driving at random times the car will jerk, almost like the engine is knocking? Even worse, when I come to a complete stop or very slow roll, the engine WILL CUT OFF, however the electronics and everything else stay on. It basically goes into the exact same mode you can put the car in by pressing the start button without using the brake at the same time to start the car. It's only at this time will the Engine light come on. The car could still be in Drive, and go into this mode. I have to stop, in the middle of traffic, put car into park, and then start the car back up. This is obviously concerning, and it seems like it's happening more and more. What is going on here?
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11-02-2017, 11:39 PM	#2
QuietQuirk Enlisted Member 16 Rep 37 Posts Drives: 335i Join Date: Jun 2013 Location: North America iTrader: (0)	Nobody?
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11-03-2017, 07:01 AM	#3
markv123 Private First Class 45 Rep 139 Posts Drives: . Join Date: Jan 2016 Location: Sydney iTrader: (0)	You may already know but it is handy to have your cars codes read so that it can be used as a starting point. In terms of your issues, one, of many, possibilities may be that you are suffering an air leak somewhere. These cars are advanced however the same principles for an engine to run still apply. Power, air and fuel. - Your car starts so you can rule that out. - Starting your car on cold start will cause fuel and air to be pushed through - In my experience with cars it sounds like your fuel pump is cutting out (akin to when you're low on fuel) but since it starts up again and keeps running then it may not be that. - Leaves me with air. You could have a air leak somewhere. Listen for one or perform a smoke test. When the car is warm the idle will not be as high as cold start so it will not force air in. Now, that's just a little old school thinking on my part and as I said at the start, a code check on these cars will help put you in the right direction first. Keep us posted. Hope you get it sorted.
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11-03-2017, 07:22 AM	#4
John 070 Lieutenant General 1705 Rep 14,829 Posts Drives: 335i cpe Join Date: Oct 2006 Location: ZSP/ZPP/ZCW iTrader: (0)	When my car was very new (I am the original owner/2007), the DME was replaced under warranty. There were ZERO codes, car would simply die in the middle of traffic, and I had to limp to the shoulder. After multiple trips to the dealer, it did it while they had it. This enabled them to open a case with BMW and upgrade the DME from a MSD80 to a MSD81. But this was long ago....never did it again, not even once... p.s. same thing, would never be an issue whatsoever restarting the motor. Which is why the dealership could not do anything without witnessing it. I remember my wife's aunt telling me get rid of that POS, you can't even drive it, what's the point? just for the heck of it, I googled and see there is a service when you provide the part, so prolly a known issue.... https://www.ebay.com/itm/BMW-MSD80-M...-/262822313971 Last edited by John 070; 11-03-2017 at 07:34 AM..
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11-03-2017, 08:43 AM	#5
The_E92_Fan V8 Bait 206 Rep 769 Posts Drives: your mom Join Date: Jun 2016 Location: your moms house iTrader: (0)	an MHD log would help. if either of your fuel pumps are shot or your engine is struggling to breathe, your low and high pressure fuel sensors will reflect, also you can look at STFY %. if you're nearing 34%, your pumps are failing. If your LPFP is not at 80 at idle, and dips below 45 on a pull, you may have an issue __________________ Broke AF
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