Ran out of gas, now I have misfires under heavy acceleration

WTP07 · 07-18-2019, 12:55 PM

As the title says....

I did a stupid and forgot the car was running in the laneway, and let it run completely out of gas. Then of course, all of the hvac, stereo, lights, etc were still on and the battery went flat.

Charged the battery, got gas, got it restarted, everything good....not so much.

Now, whenever I do any heavy acceleration, I get misfires. Light to moderate acceleration is just fine, but as soon as it gets above 4k RPM, misfires again.

If I continue to accelerate hard, the CEL will illuminate and I need to shut the car off and on again to stop the misfiring.

Codes are cylinder misfires.

So, my questions is, what did I fuck up? Where to start? HPFP? LPFP? Injectors? Plugs?

I don't want to start throwing parts at it until I get a bit of direction.

Thanks for your help!

I can post data logs or specific codes if need be. (Bimmergeeks ProTool)

Cheers.

type-dRew · 07-18-2019, 01:16 PM

Probably sucked up some bottom of the gas tank trash and contaminated your fuel system.

Have you cleared the codes since getting them initially and they came right back?

WTP07 · 07-18-2019, 01:47 PM

Quote:

Originally Posted by type-dRew

Probably sucked up some bottom of the gas tank trash and contaminated your fuel system.

Have you cleared the codes since getting them initially and they came right back?

Yes, I can clear the codes and as long as I drive moderately, no misfire, no codes. Accelerate hard and I get the misfires, and consequently the codes.

IF I have some crap in the fuel system, where to I look? Injectors? Fuel pump pickup screen?

buster84 · 07-18-2019, 04:08 PM

I'm not sure how long the lpfp stays on after the car cuts out, but if you car was idling for a while and running on fumes then the gasoline didnt cooldown the fuel pump and could have overheated. I would think as long as you have the fuel filters in place at the bottom of the pump you shouldnt have ingested anything in your fuel system.

My suggestion is to start by loging the issue your having to see if maybe the lpfp overheated and started to malfunction. If its not that, then move onto your coils/plugs because it might also just be a fluke that something else decided to malfunction at the sametime you ran out of gas lol.

Cabdriver · 07-18-2019, 09:44 PM

Run a bottle of techron, fesh tank of gas and make sure the battery is charged up via a trickle charger overnight.
Could be (as noted above) dirty, bottom ofbthe tank gas, water/condensation was sucked up. Also, if you jumped it, the battery is far from charged up which effects all electronic components, they wont be running optimally. Need to get the battery properly charged up.
After that, if the issue persists, run some logs to see what the spark timing, afr, etc look like.

Good luck

07-18-2019, 12:55 PM	#1
WTP07 Noob 0 Rep 5 Posts Drives: '10 335ix, '12 Santa Fe, 08FJR Join Date: Mar 2019 Location: SW Ontario iTrader: (0)	Ran out of gas, now I have misfires under heavy acceleration As the title says.... I did a stupid and forgot the car was running in the laneway, and let it run completely out of gas. Then of course, all of the hvac, stereo, lights, etc were still on and the battery went flat. Charged the battery, got gas, got it restarted, everything good....not so much. Now, whenever I do any heavy acceleration, I get misfires. Light to moderate acceleration is just fine, but as soon as it gets above 4k RPM, misfires again. If I continue to accelerate hard, the CEL will illuminate and I need to shut the car off and on again to stop the misfiring. Codes are cylinder misfires. So, my questions is, what did I fuck up? Where to start? HPFP? LPFP? Injectors? Plugs? I don't want to start throwing parts at it until I get a bit of direction. Thanks for your help! I can post data logs or specific codes if need be. (Bimmergeeks ProTool) Cheers. __________________ "I will choose a path that's clear, I will choose freewill"
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07-18-2019, 01:16 PM	#2
type-dRew Major 641 Rep 1,245 Posts Drives: 2009 335i xDrive Join Date: Feb 2019 Location: Newport MI iTrader: (0)	Probably sucked up some bottom of the gas tank trash and contaminated your fuel system. Have you cleared the codes since getting them initially and they came right back? __________________ 2009 335i xDrive AT / 177k+ miles PSP 750ic / Fuel-It! Stage 1 / BMS CP / Sutphin Tuning / RFP E50 11.61 @ 117.5 New setup; Covid 19Ts on RFP 93 + ARM inlets, dp, VTT cp and PSP outlets
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07-18-2019, 04:08 PM	#4
buster84 Major 339 Rep 1,185 Posts Drives: 2009 335I X-Drive E90 Join Date: Nov 2012 Location: Orlando iTrader: (2)	I'm not sure how long the lpfp stays on after the car cuts out, but if you car was idling for a while and running on fumes then the gasoline didnt cooldown the fuel pump and could have overheated. I would think as long as you have the fuel filters in place at the bottom of the pump you shouldnt have ingested anything in your fuel system. My suggestion is to start by loging the issue your having to see if maybe the lpfp overheated and started to malfunction. If its not that, then move onto your coils/plugs because it might also just be a fluke that something else decided to malfunction at the sametime you ran out of gas lol. __________________ 2015 BMW M4 F83 2009 335i X-Drive \| GC 2.0 Turbos (sold) 2009 335i e93 (Sold) 2007 Bmw X5 (Sold)
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07-18-2019, 09:44 PM	#5
Cabdriver Private First Class 52 Rep 164 Posts Drives: 2009 E90 335i Join Date: Jun 2016 Location: NJ iTrader: (0)	Run a bottle of techron, fesh tank of gas and make sure the battery is charged up via a trickle charger overnight. Could be (as noted above) dirty, bottom ofbthe tank gas, water/condensation was sucked up. Also, if you jumped it, the battery is far from charged up which effects all electronic components, they wont be running optimally. Need to get the battery properly charged up. After that, if the issue persists, run some logs to see what the spark timing, afr, etc look like. Good luck
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