[GearHead335i]

I searched and couldn’t find this exact scenario so here it goes;

Vehicle: 2009 335i n54
Mods: VRSF Catless Downpipes to;
GENUINE BMW Performance Exhaust
VRSF charge-pipe
HKS blowoff valve
Burger Motorsport dual cone intake
CX Racing front mount intercooler
RB PCV valve
MHD Stage 2 tune
NGK 5992 1 step colder spark plugs
Delphi coils

Still having CEL come on for BANK1 and BANK2 o2 sensors. Now I have a VRSF DP fix and went to install it the other day to sort this issue and am I correct in saying you have to have a jb4 to use their DP fix? I need to pass inspection in NY and even at a “friendly” shop they said they can’t do anything about it, if it’s showing incomplete it won’t pass.

If my after cat o2 sensors were actually bad would it show up like it is or would mhd mask it? Need help as my temp inspection is almost up.

This is what it always pops up with after I cycle the system (drive 50+ Miles)

[GearHead335i]

And this is what it shows directly after me clearing the codes. As stated it always goes back to the
-low pressure fuel (mhd said its normal?)
-o2 sensor after cat bank 1 signal
-o2 sensor after cat bank 2 signal
-occasional 30ff

[GearHead335i]

Bumpppp

[BSM n54iS]

Why do you have a cel with mhd stage 2 is what I'm curious about

[GearHead335i]

Originally Posted by BdSM n54iS

Why do you have a cel with mhd stage 2 is what I'm curious about

Same here lol

[falconey]

The dp fix should work without a jb4. If it's not an adjustable dp fix you may need another one unfortunately. I believe if it fools the ECU by sending a certain amount of voltage.

[jwalker87]

Originally Posted by falconey

The dp fix should work without a jb4. If it's not an adjustable dp fix you may need another one unfortunately. I believe if it fools the ECU by sending a certain amount of voltage.

I believe this is true as well. Is the INCOMPLETE after doing the emissions drive cycle? There is a BMW-specified pattern of driving speeds and times in order for the system to run diagnostics, which is required to achieve READY or PASS. The catalysts are the most difficult, as they require you to drive 40-60mph for 15-20 minutes, below 3,000 rpm, with minimal throttle changes.

I believe INCOMPLETE is not necessarily a bad thing, you just need to run the cycle. This is from my own experience with an MHD backend flash, JB4, and catless DPs on my N54.

[jeddo45]

Originally Posted by jwalker87

I believe this is true as well. Is the INCOMPLETE after doing the emissions drive cycle? There is a BMW-specified pattern of driving speeds and times in order for the system to run diagnostics, which is required to achieve READY or PASS. The catalysts are the most difficult, as they require you to drive 40-60mph for 15-20 minutes, below 3,000 rpm, with minimal throttle changes.

I believe INCOMPLETE is not necessarily a bad thing, you just need to run the cycle. This is from my own experience with an MHD backend flash, JB4, and catless DPs on my N54.

I am running an MHD stage 2+ with catless downpipes without DP fix, and I get no check engine light, but my catalytic rediness just comes up as incomplete.

OP you shouldn't be getting a check engine light with/ without the DP fix if your running MHD which means the issue is somewhere else.

When did you start getting a check engine light? My guess is you could have screwed up the install of the DP fix and you need to check that. That is where I would start.

[Nexus313]

Change your LPFP sensor.

Then check back. I'm guessing the sensors bad which in turn is messing with your fuel trims which is then making your o2s go wild.

Make sure you clear adapations after you change, then clear codes too. Run the cycle again after that with the dp fix.

[GearHead335i]

Originally Posted by falconey

The dp fix should work without a jb4. If it's not an adjustable dp fix you may need another one unfortunately. I believe if it fools the ECU by sending a certain amount of voltage.

DP is the adjustable one.

Originally Posted by jeddo45

I am running an MHD stage 2+ with catless downpipes without DP fix, and I get no check engine light, but my catalytic rediness just comes up as incomplete.

OP you shouldn't be getting a check engine light with/ without the DP fix if your running MHD which means the issue is somewhere else.

When did you start getting a check engine light? My guess is you could have screwed up the install of the DP fix and you need to check that. That is where I would start.

I’ve been getting check engines for awhile maybe 3 months after I installed my downpipes 2 years ago. Also I haven’t installed th DP fix yet.

Originally Posted by Nexus313

Change your LPFP sensor.

Then check back. I'm guessing the sensors bad which in turn is messing with your fuel trims which is then making your o2s go wild.

Make sure you clear adapations after you change, then clear codes too. Run the cycle again after that with the dp fix.

Hmmm I thought that lpfp code was normal if you had mhd. I’ve been getting that code for as long as I can remember.

[Paanzerfaust]

Originally Posted by Quinnhogue7

DP is the adjustable one.



I’ve been getting check engines for awhile maybe 3 months after I installed my downpipes 2 years ago. Also I haven’t installed th DP fix yet.




Hmmm I thought that lpfp code was normal if you had mhd. I’ve been getting that code for as long as I can remember.

Who told you the lpfp code was normal? I've never heard of that and never seen it myself.

MHD will suppress the CEL and put the cat codes as shadow codes as long as you have the "stock downpipes" box unchecked, but it won't make the catalyst show anything other than INCOMPLETE.

The fact that you have more than just codes for the cats and get an actual CEL really makes it sound like you have an actual problem, and judging from all the o2 codes (especially the one saying "ageing") I'd say it's something there. Those definitely aren't normal with MHD, and 30FF is always a pretty good sign that something isn't right. DP fix isn't gonna fix that.

[-JrHatch-]

Do you have catted down pipes checked under the MHD options? If so this could cause this issue, just had a friend with the same thing and un checking that box fixed it

[Nexus313]

The lpfp code isn't normal.. quick way to test if it's mhd related issue, just revert back to stock map.

[IllSic_Design]

Yeah change the low pressure sensor, that code will go away. I believe there is a different fuel pump shadow code that you are thinking of that is normal.

[Nexus313]

Originally Posted by IllSic_Design

Yeah change the low pressure sensor, that code will go away. I believe there is a different fuel pump shadow code that you are thinking of that is normal.

Yup the 2aaf is normal. Not the lpfp code.

[Supra2k6]

i'm on the same boat. FBO

so i have mhd on stage 0 right now for emission testing with the dp fix and i cannot get catalyst ready it shows incomplete after 50 miles and few cycles of driving.

I figure my issue is MHD is auto deleting codes so now i checked the box that says catted/stock dp. so MHD should not delete anything and allow the DP fix do it's job.

i emailed MHD to see their suggestion. OP i don't think you should be getting those codes only the normal catless codes that everyone gets.

[boneheaddoctor]

Stage zero by my understanding is effectively stock maps no code suppression, and you need 100-150 miles of driving for that to complete, 50 is insufficient. If I misunderstood that I'm sure someone will correct me.

[GearHead335i]

Originally Posted by Paanzerfaust

Who told you the lpfp code was normal? I've never heard of that and never seen it myself.

MHD will suppress the CEL and put the cat codes as shadow codes as long as you have the "stock downpipes" box unchecked, but it won't make the catalyst show anything other than INCOMPLETE.

The fact that you have more than just codes for the cats and get an actual CEL really makes it sound like you have an actual problem, and judging from all the o2 codes (especially the one saying "ageing") I'd say it's something there. Those definitely aren't normal with MHD, and 30FF is always a pretty good sign that something isn't right. DP fix isn't gonna fix that.

Nope nothing is checked in the mhd other than exhaust burble.

Originally Posted by -JrHatch-

Do you have catted down pipes checked under the MHD options? If so this could cause this issue, just had a friend with the same thing and un checking that box fixed it

Nope nothing checked.

Originally Posted by Nexus313

The lpfp code isn't normal.. quick way to test if it's mhd related issue, just revert back to stock map.

Yeah I believe it shows up with and without mhd.

Originally Posted by IllSic_Design

Yeah change the low pressure sensor, that code will go away. I believe there is a different fuel pump shadow code that you are thinking of that is normal.

Originally Posted by Nexus313

Yup the 2aaf is normal. Not the lpfp code.

Yeah that's what I was thinking of.

Originally Posted by Supra2k6

i'm on the same boat. FBO

so i have mhd on stage 0 right now for emission testing with the dp fix and i cannot get catalyst ready it shows incomplete after 50 miles and few cycles of driving.

I figure my issue is MHD is auto deleting codes so now i checked the box that says catted/stock dp. so MHD should not delete anything and allow the DP fix do it's job.

i emailed MHD to see their suggestion. OP i don't think you should be getting those codes only the normal catless codes that everyone gets.

Hmmmm I did not know I had to set it to 0 but regardless I shouldn't be getting that check engine.



Do you guys think that replacing the 2 o2 sensors after the cats is a good idea? Or do you think it's something else just throwing them off?

[Nexus313]

Originally Posted by Quinnhogue7

Nope nothing is checked in the mhd other than exhaust burble.



Nope nothing checked.



Yeah I believe it shows up with and without mhd.





Yeah that's what I was thinking of.



Hmmmm I did not know I had to set it to 0 but regardless I shouldn't be getting that check engine.



Do you guys think that replacing the 2 o2 sensors after the cats is a good idea? Or do you think it's something else just throwing them off?

Lol 2 o2 sensors being changed is way more expensive than replacing the lpfp sensor. Start with that first. It's very unlikely that they both went bad at once.

[Paanzerfaust]

Originally Posted by Quinnhogue7

Nope nothing is checked in the mhd other than exhaust burble.



Nope nothing checked.



Yeah I believe it shows up with and without mhd.





Yeah that's what I was thinking of.



Hmmmm I did not know I had to set it to 0 but regardless I shouldn't be getting that check engine.



Do you guys think that replacing the 2 o2 sensors after the cats is a good idea? Or do you think it's something else just throwing them off?

Well you definitely need the "stock/catted downpipes" box checked for it to not clear the codes automatically/for it to check for cat readiness which the dp fix needs to work correctly, so start there. You could even be on a tuned map and have that checked and it'll let the dp fix work, has nothing to do with which map you're on or needing to be on map 0. But I still think you have something else wrong judging by all your other codes.

[GearHead335i]

Originally Posted by Paanzerfaust

Well you definitely need the "stock/catted downpipes" box checked for it to not clear the codes automatically/for it to check for cat readiness which the dp fix needs to work correctly, so start there. You could even be on a tuned map and have that checked and it'll let the dp fix work, has nothing to do with which map you're on or needing to be on map 0. But I still think you have something else wrong judging by all your other codes.

Ok but first a dp fix can be installed without a jb4? I looked for directions on how to do it and I got to the DMV where the smaller sub connector is and from that point on the directions direct you as if you have A jb4.

Second the stock catted dp option is indeed supposed to be checked even if I have catless? You're saying once I have the dp fix in, and the LPFP sensor fixed, i check the stock catted dp option and cycle the car right?

Thanks everyone for the help!!

[jwalker87]

I've attached the installation instructions, which have a section for installation both with and without JB4. I've also attached the emissions drive cycle procedure. This can take anywhere from 15 to 99999 miles to complete based on your driving routine, so having it on hand, and maybe taking a dedicated drive to achieve it, may help.