[Mikey335]

2008 335i
catless downpipes
DCI
jb4

During some spirited driving this evening since it was so nice out... I heard a loud POP then went reduced power, i didn't get check engine but I did get

29F3 Faulty Low Fuel Pressure Sensor(This has been on/off for 3-4months and has given me no issues until now, Maybe?)
29DC Cylinder Injection switch-off
2C77 Lambda probe behind catalytic converter

After the pop sounded like the car was misfiring for the next minute until i made it home.

After researching people were saying possible low pressure fuel pump. So I wanted to go test it.

I reset the codes and went back out, everything was running perfectly fine under low throttle.

When the car hit 3-4k RPM it really surged on me, like I'd feel like I'd have power for a second then bam it was back off. I wasn't really comfortable to try and get a log. Even when it felt like I'd have the power, it was significantly lower than usual.

After doing a few pulls trying to get a decent log with a longer duration than a few seconds I got CEL

29F3 Faulty Low Fuel Pressure Sensor
30FE Boost over target
3100 low boost mode engaged.

According to the logs I didn't save... I was always low on boost, max of around 10psi. Also the throttle on the graph was going full open full close back and forth, not sure if this has anything to do with the surging but i was full pedal the entire time.

If anyone has any suggestions on what route to go with these vastly different codes, I'm all ears.

**I did pull the charge pipe thinking that loud POP could of been it blowing apart, but I did not seem to find any noticeable cracks or breaks.

[Mikey335]

Bump for help

[Chris@VargasTurboTech]

Posting the logs (link to datazap) is always much easier to diagnose -just guesswork before then.

[torrque]

with a faulty low pressure sensor, you can get lambda codes also, due to mismatched air-fuel ratios. Don't drive it until you change that sensor; put it on stock map until you do so.

[Mikey335]

https://datazap.me/u/mikey335/log-15...data=1-3-4-5-9

https://datazap.me/u/mikey335/log-15...log=0&data=1-4

I know you guys normally want WOT logs... but im really not comfortable, the car gets pretty jerky. The rpm's bounce like crazy, the logs aren't showing it but it gives a surging woosh woosh noise.

I fixed all my codes this past week I think. I did Intake valve cleaning, replaced charge pipe, replaced spark plugs. still same result

[hcopeland]

Originally Posted by Mikey335

https://datazap.me/u/mikey335/log-15...data=1-3-4-5-9

https://datazap.me/u/mikey335/log-15...log=0&data=1-4

I know you guys normally want WOT logs... but im really not comfortable, the car gets pretty jerky. The rpm's bounce like crazy, the logs aren't showing it but it gives a surging woosh woosh noise.

I fixed all my codes this past week I think. I did Intake valve cleaning, replaced charge pipe, replaced spark plugs. still same result

No expert with reading logs but your low fuel pressure seems to be constant. The surging makes me think that its got to be cylinder or fuel delivery problem. Run a test on your Injectors with INPA. post it here?

[only1harry]

Got any updates or made any progress eliminating other things?

How about the HPFP? My 2011 335i xDrive did the same thing yesterday. Loud POP and then power loss. The exhaust is very buzzy/loud too now. No mods whatsoever other than suspension stuff, and only 43k miles Mine revs fine but the car accelerates very slowly. I also got the SES light - Service Engine Soon. No CEL on the dashboard other than SES.

[CoralRed335XI]

Originally Posted by only1harry

Got any updates or made any progress eliminating other things?

How about the HPFP? My 2011 335i xDrive did the same thing yesterday. Loud POP and then power loss. The exhaust is very buzzy/loud too now. No mods whatsoever other than suspension stuff, and only 43k miles Mine revs fine but the car accelerates very slowly. I also got the SES light - Service Engine Soon. No CEL on the dashboard other than SES.

Sounds like your charge pipe broke.

[Mikey335]

Originally Posted by only1harry

Got any updates or made any progress eliminating other things?

How about the HPFP? My 2011 335i xDrive did the same thing yesterday. Loud POP and then power loss. The exhaust is very buzzy/loud too now. No mods whatsoever other than suspension stuff, and only 43k miles Mine revs fine but the car accelerates very slowly. I also got the SES light - Service Engine Soon. No CEL on the dashboard other than SES.

Harry, Sounds similar to the problem I had after I had gotten the jb4 straightened out... I found out that my charge pipe was cracked and I was losing boost. After I replaced my charge pipe I had done a few pulls to view logs and found out the outlet side of my intercooler apparently wasn't clipped properly. Both of these were causing me massive boost leak. Once I had done all that, I went ahead and bought new silicone vacuum lines for everything. Costed me like 30 shipping included, that pretty much got my car back 100%


It turned out that my menu 4 was at setting 2(backend flash) and im not running backend flash.

I'm guessing it's because I was running off a hex from roughly 2 years ago, I had updated it and when I did... Settings went haywire all over the board. It's a shame there is no factory reset. I had to get assistance finding out what the default settings are because jb4 has disabled factory reset.

Once I made changes to jb4 how it SHOULD of been, the car ran great.

[Cabdriver]

Low pressure sensor code is common that sensor is is used to diagnose lpfp. I've had mine throw the code for 40k no issues with my pump. Yours maybe on it's way out though.

Check your intake piping, specifically the charge pipe, boost over limit is a telltale sign your cp popped, dont just do a visual, take it off and examine it, make sure the c-clip is secured when you remove it. Could have a crack in it that only appears under full or partial boost. I would wager that's your problem and the lpfp is just the sensor on it's way out.

[b92]

Originally Posted by Cabdriver

Low pressure sensor code is common that sensor is is used to diagnose lpfp. I've had mine throw the code for 40k no issues with my pump. Yours maybe on it's way out though.

Check your intake piping, specifically the charge pipe, boost over limit is a telltale sign your cp popped, dont just do a visual, take it off and examine it, make sure the c-clip is secured when you remove it. Could have a crack in it that only appears under full or partial boost. I would wager that's your problem and the lpfp is just the sensor on it's way out.

I agree, my money is on the chargepipe.