Stalling at a quarter tank of fuel

[Houranimd49]

Hi Guys!

2011 135 (N55) with MHD Stage 2 tune, catless downpipe, and BMS intake.

For the last 5 tanks of fuel, without hesitation, the car gets a half engine light with service engine soon followed by stalling out. Attached are the codes below.

Before anyone suggests that there is no gas despite 1/4 tank showing, there is gas. I would refill at 1/4 tank and only 8-10 gallons would fill. Even then, car won't return to normal by refilling fuel.

The car would return back to normal when I would reflash back to stock tune. Followed by reflashing back to stage 2 and then again, car would act fine.

I suppose the codes are pointing toward fuel rail sensor? I appreciate anyone's input on what could be happening.

[Andrewbens]

Without reading the codes I would say the fuel pump is going bad and to change the fuel pump filter.

[Houranimd49]

Originally Posted by Andrewbens

Without reading the codes I would say the fuel pump is going bad and to change the fuel pump filter.

Low pressure or high pressure?

[Andrewbens]

Originally Posted by Houranimd49

Low pressure or high pressure?

I would say low pressure. The only way to know for sure is to run a log on the car and see what the load of the fuel pump is at to see how hard it’s working at idle.

[ShocknAwe]

I'd just check your lines, make sure your bucket is refilling. I'm assuming this is a stock bucket and not a bucket less setup without a hydromat?

[Houranimd49]

Originally Posted by Andrewbens

I would say low pressure. The only way to know for sure is to run a log on the car and see what the load of the fuel pump is at to see how hard it’s working at idle.

Which parameter on MHD is this? I see a rail fuel sensor parameter which I presume is the HPFP.

[Houranimd49]

Originally Posted by ShocknAwe

I'd just check your lines, make sure your bucket is refilling. I'm assuming this is a stock bucket and not a bucket less setup without a hydromat?

I can’t pretend to understand what this means haha. Sorry for my ignorance. The car is otherwise stock from what I mentioned on the original post.

[ShocknAwe]

Originally Posted by Houranimd49

I can’t pretend to understand what this means haha. Sorry for my ignorance. The car is otherwise stock from what I mentioned on the original post.

The LPFP sits inside a bucket with a venturi low flow feed system and fuel return lines that run from the tank regulator to the bucket. There's a fill float inside too for fuel level.

What I'm wondering is if your fuel returns aren't functioning or if you don't have any (PO modified car and installed a bucket less pump)

Not suspicious of a bad low pressure pump itself that's typically seen under load. But a log would certainly help.

Log FPL, fuel rail, afr1/2 stft1/2 and timing all cylinders

[Houranimd49]

Originally Posted by ShocknAwe

The LPFP sits inside a bucket with a venturi low flow feed system and fuel return lines that run from the tank regulator to the bucket. There's a fill float inside too for fuel level.

What I'm wondering is if your fuel returns aren't functioning or if you don't have any (PO modified car and installed a bucket less pump)

Not suspicious of a bad low pressure pump itself that's typically seen under load. But a log would certainly help.

Log FPL, fuel rail, afr1/2 stft1/2 and timing all cylinders

Today, just idling for a little while at a drive-through with just under half a tank, and the symptoms happened all over again. I was able to keep the car running to get a quick log based on the parameters you told me. I attached a picture of a below if it’s any help at all.

[ShocknAwe]

Please upload to datazap and repost