[BSM n54iS]

Starting a new thread so as to not mix things up with log attached now. Not a tune issue it seems...

Car goes into limp mode on cold starts on stage 2+ only for right now, still rough cold starts intermittent on stage 0 but not shuddering so badly to cause going into limp mode. Warm starts seem to be fine. Codes are showing for high pressure fuel pump: 2f2c and 2b2c. LPFP is below 70 while driving and before starting but bumps up to 70+ after shutoff while HPFP goes down to 70+. Log attached here. Thanks for looking and your thoughts!

https://datazap.me/u/dkopytenko/cold...g=0&data=12-22

[_N54]

Most likely a leaking injector(s). How new are yours or which index? Let the car sit overnight and pull the plugs and see if they're wet. Usually leaking injectors cause a rough start due to all that raw fuel that needs to burn off in the combustion.

[BSM n54iS]

Update:

Went driving about 2 hours later. LPFP & HPFP were both sitting at 64psi before startup, upon startup lpfp went up to 83 but then shot back down to ~62psi seconds later. HPFP seemed fine at about 700+ psi at idle after startup. HPFP reaches 2500psi on cold start, and progressively less and less the warmer the motor is. LPFP is running consistently in the low 60 psi range though.

After shutting off both lpfp and hpfp stabilize to 76psi.

It seems like my LPFP is starting to let go actually, but how long will the fuel regulator keep the pressures at what they should be in the 70psi range? Should I be concerned about that as well I'm not 100%. Anyone think it could be something else going on besides LPFP letting go?

[BSM n54iS]

Originally Posted by ///S58

Most likely a leaking injector(s). How new are yours or which index? Let the car sit overnight and pull the plugs and see if they're wet. Usually leaking injectors cause a rough start due to all that raw fuel that needs to burn off in the combustion.

Haha right, well they WERE leaking like 2 months ago (#6 failed, #5 on the way out) but BMW dealer installed all 6 brand new index 12's for me under the extended warranty. Really REALLY hate the idea they fucked up on install somehow....

I didn't have this issue before BMW touched it, nor did I weeks of driving after. Only by switching back to stage 2+ and putting cold start back on was the first instance of this happening.

...I'll pull 1 & 4 tomorrow for sake of mind.

[_N54]

Originally Posted by BdSM n54iS

Haha right, well they WERE leaking like 2 months ago (#6 failed, #5 on the way out) but BMW dealer installed all 6 brand new index 12's for me under the extended warranty. Really REALLY hate the idea they fucked up on install somehow....

I didn't have this issue before BMW touched it, nor did I weeks of driving after. Only by switching back to stage 2+ and putting cold start back on was the first instance of this happening.

...I'll pull 1 & 4 tomorrow for sake of mind.

Flash to stock and take it back to them. Let it sit there overnight and tell them it has a rough cold start after you guys replaced the injectors.

[BSM n54iS]

Originally Posted by ///S58

Flash to stock and take it back to them. Let it sit there overnight and tell them it has a rough cold start after you guys replaced the injectors.

You don't think my lpfp is an issue?

They actually noted and told me the car was still running a bit rough after they installed the injectors, so they were aware it seemed like another issue present. At the time I thought it was just new plugs needed, which I replaced a week or 2 after that. So it just doesn't seem like the injectors still after, but I'll pull some plugs and see. The lpfp being so low is a concern along with being thrown into limp mode, didn't know leaky injectors would throw me into limp mode

[stewbets]

I don't think this has anything to do with your LPFP. The pressure is a little on the low side, but certainly not in the range that should cause problems. How does the LPFP do on pulls? This looks like an injector or HPFP issue to me.

[BSM n54iS]

Originally Posted by stewbets

I don't think this has anything to do with your LPFP. The pressure is a little on the low side, but certainly not in the range that should cause problems. How does the LPFP do on pulls? This looks like an injector or HPFP issue to me.

Thanks, I'll try and do a pull today on stage 0 and see if the hpfp or lpfp dips. I'd actually rather have it be one of the pumps than BMW not being able to install brand new injectors, that would just be absurd. I mean, I could tell it was my injectors before so that's why I took it in to the dealer for free warranty repair otherwise I do all my own maintenece. When I got the car back they told me 'hey the car is still running a bit rough, something else seems to be an issue as well still'. It didn't feel like my injectors anymore either, but ya I can't say for sure yet

[BSM n54iS]

Ok 3rd gear log here, had to let up early cuz of traffic but should be enough to diagnose the pumps.

https://datazap.me/u/dkopytenko/log-...og=0&data=3-22

Was in a rush this morning, didn't pull plugs yet. If I go and find fuel on them this evening my goodness... is BMW going to get an earful I tell ya

HPFP is hitting 2500psi before tapering off. Should hpfp be holding 2500psi all through the rev band? It's been so long since I logged to be honest. LPFP is going down to 56psi but then by 3300 rpm it gets up to 76psi before tapering off back down to the 60's near 5k rpm. Fucking acting like leaky injectors wtf, how could the techs screw up something so gd simple by putting new injectors in and have them leaking from the get go.

[stewbets]

I've not had HPFP issues myself, but looking at both the logs you've posted makes me a little skeptical of yours. Check out my startup log:

https://datazap.me/u/stewbets/e85-co...0&data=0-21-22

Once the engine fires, my HPFP is over 2500 PSI in less than half a second. With yours it takes almost 3 seconds. There's a similar delay on your 3rd gear pull. Here's one of mine:

https://datazap.me/u/stewbets/3rd-ge...data=0-2-21-22

Once I go WOT, the HPFP is over 2500 PSI in less than half a second, but yours is a little over a second.

Again, you've got a HPFP code and I can see a difference in how it behaves compared to mine, but I've not personally been through this before.

[BSM n54iS]

Originally Posted by stewbets

I've not had HPFP issues myself, but looking at both the logs you've posted makes me a little skeptical of yours. Check out my startup log:

https://datazap.me/u/stewbets/e85-co...0&data=0-21-22

Once the engine fires, my HPFP is over 2500 PSI in less than half a second. With yours it takes almost 3 seconds. There's a similar delay on your 3rd gear pull. Here's one of mine:

https://datazap.me/u/stewbets/3rd-ge...data=0-2-21-22

Once I go WOT, the HPFP is over 2500 PSI in less than half a second, but yours is a little over a second.

Again, you've got a HPFP code and I can see a difference in how it behaves compared to mine, but I've not personally been through this before.

Thanks a bunch for those logs! You are right calling out the HPFP, that startup log of yours side by side to mine really make it stand out haha.

Also looking at how the pump is behaving looks bad. The amplitude is small but number of fluctuations in pressure, where its bouncing up and down then smooths out then back to bouncing over and over again. Looks to be pretty erratic at idle too.

[BSM n54iS]

Plugs and everything are dry, checked #'s 2&4 and no fuel or any smell of anything really. Getting a new hpfp now. Should I go ahead and replace the hpfp sensor along with it, might as well right?



Not sure how I feel about the look of these after less than 1k miles but they are running fine

[BSM n54iS]

Got a new hpfp in and stage 2+ cold start is much, much better. Thanks to everyone for the help! I'm curious if those sharp fluctuations are healthy though for idle..? Both early and kinda later on...

https://datazap.me/u/dkopytenko/new-...g=0&data=19-20

[Saif2018]

Originally Posted by BdSM n54iS

Got a new hpfp in and stage 2+ cold start is much, much better. Thanks to everyone for the help! I'm curious if those sharp fluctuations are healthy though for idle..? Both early and kinda later on...

https://datazap.me/u/dkopytenko/new-...g=0&data=19-20

You can already see its beginning to stabilise towards the end of that log.

Log it for a couple of Minutes and it should stabilise after a while,

[stewbets]

Originally Posted by BdSM n54iS

Got a new hpfp in and stage 2+ cold start is much, much better. Thanks to everyone for the help! I'm curious if those sharp fluctuations are healthy though for idle..? Both early and kinda later on...

https://datazap.me/u/dkopytenko/new-...g=0&data=19-20

Awesome! Thanks for following up!

[BSM n54iS]

Originally Posted by stewbets

Awesome! Thanks for following up!

You bet! Thank you

[rsyed07]

How many miles did you hpfp last?

[BSM n54iS]

Originally Posted by rsyed07

How many miles did you hpfp last?

108k.

Water pump was just done at like 106k.