[Spoolin1]

Hey guys,

Need your help.

I have my CPO warrantied 335i at the local dealer for the P29F3 fuel pressure sensor code that is shadowing and won't clear; no check engine light. They just called and stated that it won't cause any issues and they have put that in righting on the receipt. Is this true that no issues will occur? I've heard that even though it's a shadow code, the ECU will still pull power/timing, etc. Don't know if this is true or not and just trying to figure out if I should make them change the fuel pressure sensor because of the code or just not worry about it. I do have a new AMS intercooler going on and Cobb stage 1+ tune and don't want to be losing power because of this shadow code or worse, hurt the engine, fuel system, etc.

[cn555ic]

I had that code also for a long time. Car drove fine for a while and everytime I went to clear it, the code came back time and time again. It is a faulty sensor for sure, but when it finally takes a crap you will know for sure as the car will misfire and won't allow you to apply half or full full throttle. You can cruise with it normal but as soon as you got WoT it will sputter and misfire. I would tell them to change it out.

[Spoolin1]

Thanks bud.

[Spoolin1]

Well, I just spoke to my dealer and they can't warranty cover a shadow code until it actually shows the check engine light or fault and then BMW will cover it under warranty. I guess I'll just have to wait until it goes out completely. The tech even knew it was about to go out; what a bunch of crap. Maybe I'll get lucky and my turbo's, fuel pump, coils and injectors will go out at the same time the fuel pressure sensor takes a crap and I can then get it all fixed.

BTW the car only has 29k miles and is a late Dec 07 built car. I've had this car in for more warranty crap than all of the cars I've owned put together and I've had A LOT!

[2nice89]

Originally Posted by cn555ic

I had that code also for a long time. Car drove fine for a while and everytime I went to clear it, the code came back time and time again. It is a faulty sensor for sure, but when it finally takes a crap you will know for sure as the car will misfire and won't allow you to apply half or full full throttle. You can cruise with it normal but as soon as you got WoT it will sputter and misfire. I would tell them to change it out.

He is right... I had this problem and the car misfires like crazy at wot...i would beg them to swap it out lol

[Spoolin1]

I tried and even told them that I'll be back as soon as the CEL comes on and it goes out, so it's a little ridiculous to not go ahead and change it out beforehand if you know it'll go out eventually.

[cn555ic]

The sensor cost about 100 bucks or so and it's not hard to change if you have some knowledge of the N54 engine and how to get stuff off. Might worth to do it yourself like I and many have done before

[Spoolin1]

Yeah, I usually do most everything myself but in this case, having the CPO; I'd rather just leave it for them when it goes out. I'm sure the injectors and other things will be going out soon too as it seems to be a regular occurance, so it'll be on them.

Thanks for the advice though, I'll keep it in mind.

[neilvosko]

The ecu will run a default map with that code, but like the rest of us change that sensor yourself its 70 bux which is like 20 bux more than deductible for cpo but you know it will be done right

[ksalih]

I've got The same code..but only as of last night. 40/60 mix of e85/91 and wot in 3rd and I missfired ...threw the code 29F3 directly after. Now I'm having issues wot in any gear. I might have some bad e85..or maybe I should add some more 91 to my mix to dilute the e85. Could this be a failing lpfp rather than just a failing sensor?

[maximum96]

You should log, 29f3 u might be leaning out, too much e85,
Faulty lpfs will not cause any issues, just inability to los lpfp, many have ran with this ghost code, including me, your misfires could be due to other factors, probably sparkplugs, carbon buildup, etc.

[cn555ic]

When that sensor finally goes that's the symptoms The car will have. Keep trying wOt and next thing you will get is a HUGE backfire like someone shot a rifle and then check engine light

[ksalih]

Originally Posted by maximum96

You should log, 29f3 u might be leaning out, too much e85,
Faulty lpfs will not cause any issues, just inability to los lpfp, many have ran with this ghost code, including me, your misfires could be due to other factors, probably sparkplugs, carbon buildup, etc.

Its this. Diluted The E85 with 91 and I've been okay. Need to get the inline lpfp...

[BMWM.D.]

Originally Posted by Spoolin1

I tried and even told them that I'll be back as soon as the CEL comes on and it goes out, so it's a little ridiculous to not go ahead and change it out beforehand if you know it'll go out eventually.

The problem with that solution is that the 29F3 fault will not usually ever set a check engine light at all. Usually it's a "hard" fault and the low-side fuel pressure reading defaults to a substitute value -- which means the DME doesn't know the true pressure in the low-pressure fuel system. This could affect how the engine starts, how the DME controls the fuel pump, and other possible performance issues.

I'd replace it ASAP if it were my car -- be it out of my own pocket or not.

[maximum96]

Ive had the lpfs error for about a yyear and not able to clear, logging on the jb4 shows it pinned to the max value, never had a problem, just not able to log the lpfp. My question is, will the lpfp alwats be running at max potential, in theory decreasing the lpfp life? Never had a problem starting and always takes up to 40% e85 with 93 good....

[Spoolin1]

Thanks guys. I may just go ahead and replace it then. Could you tell me the best place to get one cheap? Also, how soon until the new one may start having issues also? Is it pretty much a ~20k mile issue for regular swaps for a new one?

[neilvosko]

Yep, second cn555.
Change it for 80 bux shipped from turner or other BMW places, you will lean out at wot because the backup map the d e runs when that sensor is bad is not enough.
Mad props to Cn555, major contributor here

[neilvosko]

Originally Posted by maximum96

Ive had the lpfs error for about a yyear and not able to clear, logging on the jb4 shows it pinned to the max value, never had a problem, just not able to log the lpfp. My question is, will the lpfp alwats be running at max potential, in theory decreasing the lpfp life? Never had a problem starting and always takes up to 40% e85 with 93 good....

Terry made a vid from bms, it's a base map that dme runs that leans out on e85 FBo car

[Spoolin1]

Is it the low fuel pressure sensor at turner motorsports; part number 13537614317? Its listed for ~$67.

[maximum96]

13537614317 yes

[Spoolin1]

Cool; thanks bud.

[neilvosko]

13537614317
thats the one, make sure to get a free 2013 calendar with your order