[435iKev]

I have a 2014 BMW 435i that recently stalled. I am currently FBO Stage 2 with BM3. I was sitting at a stop light and the car suddenly went into neutral and engine turned off. I tried starting the car but it wouldn’t start. I ran a diag and got 11B401 and 11A401 codes. The next day the car runs fine with no codes.

My mechanic thinks it’s a lpfp issue since I’ve already upgraded the hpfp (xdi-35), but they can’t confirm since the car is running fine with no codes. It’s been 2 days and they can’t mimic the issue. What are your thoughts? I’m thinking it’s either the lpfp or ekp module. I’ve heard of ekp modules overheating but only on upgraded lpfp, I have an OEM one. I’m leaning towards lpfp since my car has 100,000 miles and it’s probably about time to change it.

[thejeremyman9]

Are you running Emix?

I would probably also lean EKP or LPFP.

[435iKev]

Originally Posted by thejeremyman9

Are you running Emix?

I would probably also lean EKP or LPFP.

I’m mostly on 91 but will occasionally run an E30 mix. I don’t plan on running a higher mix or upgrading turbos.

How would you tell if it’s ekp or lpfp? My mechanic ran a test and the flow on the lpfp and hpfp is normal so they’re stumped on what the problem is. Could it be that the lpfp is giving out (not fully failed) and that’s what caused the stall? Or maybe the ekp overheated but cooled down and that’s the reason why my car is running fine now.

[thejeremyman9]

Originally Posted by 435iKev

Could it be that the lpfp is giving out (not fully failed) and that’s what caused the stall? Or maybe the ekp overheated but cooled down and that’s the reason why my car is running fine now.

The problem is it could be both of those things. I asked about emix because higher emixes would stress the EKP and LPFP more, and could in theory overheat EKP even on stock LPFP. But it sounds like you arent in that situation. I would slightly lean toward an intermittent issue being more likely EKP than LPFP itself. Someone more experienced with ISTA would need to chime in on diagnostics/testing of EKP and LPFP.

[435iKev]

Originally Posted by thejeremyman9

The problem is it could be both of those things. I asked about emix because higher emixes would stress the EKP and LPFP more, and could in theory overheat EKP even on stock LPFP. But it sounds like you arent in that situation. I would slightly lean toward an intermittent issue being more likely EKP than LPFP itself. Someone more experienced with ISTA would need to chime in on diagnostics/testing of EKP and LPFP.

I agree, there’s a good chance it’s both since my car is high mileage. There’s one thing I did want to mention about how my car runs on E30. The past few times I’ve run E30 (BM3 Stage 2+ E30), I’ve had fuel cuts. Especially on a 40 roll in 2nd gear, I’d go full throttle and my car seems to be heavily restricted. This was the main reason why I was leaning towards lpfp.

Either way, if my mechanic can’t pinpoint whether it’s the LPFP or EKP, I’ll just replace both. I don’t want to just replace one, and then have the other fail later on.

[thejeremyman9]

Originally Posted by 435iKev

I agree, there’s a good chance it’s both since my car is high mileage. There’s one thing I did want to mention about how my car runs on E30. The past few times I’ve run E30 (BM3 Stage 2+ E30), I’ve had fuel cuts. Especially on a 40 roll in 2nd gear, I’d go full throttle and my car seems to be heavily restricted. This was the main reason why I was leaning towards lpfp.

Either way, if my mechanic can’t pinpoint whether it’s the LPFP or EKP, I’ll just replace both. I don’t want to just replace one, and then have the other fail later on.

Would need a log of that issue occurring to determine if its fuel supply related. Sounds good though let us know if that solves it