[vympel777]

Hi there guys,

Got the downpipe installed and burger air intake flashed to stage 2 with 93 oct rating. However, my milege dropped significally from 17-18 in the city down to 11-14 from normal driving. When i step on it i get 8-9 mpg. I have many doubts in the current flash that my oxygen sensor is not working properly but need help with MHD monitoring tool. Anyone got any expirience? Mpg is not a problem i dont mind spending extra $ for what it worth but after couple of months running stage 2 setup my engine started to acting up on cold start. It barely happens but it happens usually when i start the car in the morning Rpms would jump up and down engine shacking till i shut down the vechicle completely after restart everything seems fine. It happened couple of times already and i did fresh oil change haven't happened again. I'm wondering if my engine is running too rich on gas and that causing to cloug things up in my engine. MHD monitoring has a lot of options i just don't know where to look at. Another thing is that yearly inspection is coming up and my oxy sensor is blocked by mhd tune to prevent cel error from populating. I have a feeling that the oxygen sensor is messed up and causing bad fuel consumption. Here is some screenshots from mhd monitoring. Keep in mind that I have catless downpipe installed. My ecu log showing that oxy sensor is incomplete and evapor. system showing as incomplete as well - is that normal? I just don't have any logs before the downpipe was installed and now i can't rly tell whats normal and whats not.

[MineralF30]

Originally Posted by vympel777

Hi there guys,

Got the downpipe installed and burger air intake flashed to stage 2 with 93 oct rating. However, my milege dropped significally from 17-18 in the city down to 11-14 from normal driving. When i step on it i get 8-9 mpg. I have many doubts in the current flash that my oxygen sensor is not working properly but need help with MHD monitoring tool. Anyone got any expirience? Mpg is not a problem i dont mind spending extra $ for what it worth but after couple of months running stage 2 setup my engine started to acting up on cold start. It barely happens but it happens usually when i start the car in the morning Rpms would jump up and down engine shacking till i shut down the vechicle completely after restart everything seems fine. It happened couple of times already and i did fresh oil change haven't happened again. I'm wondering if my engine is running too rich on gas and that causing to cloug things up in my engine. MHD monitoring has a lot of options i just don't know where to look at. Another thing is that yearly inspection is coming up and my oxy sensor is blocked by mhd tune to prevent cel error from populating. I have a feeling that the oxygen sensor is messed up and causing bad fuel consumption. Here is some screenshots from mhd monitoring. Keep in mind that I have catless downpipe installed. My ecu log showing that oxy sensor is incomplete and evapor. system showing as incomplete as well - is that normal? I just don't have any logs before the downpipe was installed and now i can't rly tell whats normal and whats not.

The monitors showing "incomplete/not ready" are normal, it is like that because of the catless downpipe and tune. But to address the problem with the car shaking really badly on start up, it sounds like it could be a fuel pump or injector issue to me. Ive had rough start ups with my cars in the past so bad that i would have to restart my car 3+ times to get it to act normal, and it turned out to be my hpfp going out. Once i replaced that then everything was smooth.

Id suggest doing taking a WOT 3rd gear log, then take a look at your rail pressure & AFR and go from there.

[///M248]

Post a log or you likely wont get much help.

Have you upgraded the charge-pipe?

[vympel777]

So MHD log will only be active when I put it on 3rd gear and full throttle or at least 50% pressed on a pedal? I went to check my logs and turned out that I have none. It happened again this morning car started just fine but after ideling for a minute or so my rpms sponteniuosly started to jump down and up and in the end I had some kind of spike- rmps went up to 3k and everything stabilized to normal ideling. How do i make logs when parcked for example?

[///M248]

Originally Posted by vympel777

So MHD log will only be active when I put it on 3rd gear and full throttle or at least 50% pressed on a pedal? I went to check my logs and turned out that I have none. It happened again this morning car started just fine but after ideling for a minute or so my rpms sponteniuosly started to jump down and up and in the end I had some kind of spike- rmps went up to 3k and everything stabilized to normal ideling. How do i make logs when parcked for example?

Choose manual data logging.

If you have a manual trans, put in third gear hold at 2500 rpm and press start log at the top of the MHD app.

If you have auto trans, hold DSC off for 10 seconds. Move shifter into manual mode and put in 4'th gear, hold at 2500 rpm the press start log.

Then just punch it and shift at 6500ish, then stop the log sometime soon after that.

[vympel777]

Originally Posted by ///M248

Choose manual data logging.

If you have a manual trans, put in third gear hold at 2500 rpm and press start log at the top of the MHD app.

If you have auto trans, hold DSC off for 10 seconds. Move shifter into manual mode and put in 4'th gear, hold at 2500 rpm the press start log.

Then just punch it and shift at 6500ish, then stop the log sometime soon after that.

I see but my problem seems to be happening only on a cold start when ideling in park and what's interesting its not constant which makes it even harder to troubleshoot. I would average it out of 5 cold starts it would happen 1 or two times other times vechicle runs normal. When im driving everything seems fine. I dont think the logs will show anything abnormal on such high rpms but ill do the logs as you suggested. Im kinda dissapointed just hit over 55 k miles on my bimmer and this started to happen

[///M248]

Get some MAF cleaner and clean your MAF. Bet you got it dirty or damaged it when you put the intake on. You may need to reset adaptations as well.

[Alpine.N55]

Originally Posted by vympel777

So MHD log will only be active when I put it on 3rd gear and full throttle or at least 50% pressed on a pedal? I went to check my logs and turned out that I have none. It happened again this morning car started just fine but after ideling for a minute or so my rpms sponteniuosly started to jump down and up and in the end I had some kind of spike- rmps went up to 3k and everything stabilized to normal ideling. How do i make logs when parcked for example?

I am running MHD Stage 2 and experience the same issue with the RPMs jumping up and down, it stops as soon as I turn off the AC. My shop told me that it's time to replace spark plugs, but i'm only at 38k miles so I don't really think it's that. Hope you figure it out, because it'll help me too lol

[TheShadow]

^As the above poster said, make sure to replace plugs with properly gapped plugs. Idle issue should go away.
If that doesnt work, check fuel pumps.

[vympel777]

Okay i had performed a few tests also been monitoring my maf output and it looks like its running behind its requirement. fuel rail pressure seems to be stable no matter what high low rpms always meets the requirements and produce enough pressure. However now the Maf sensor always 0.4 - 0.5 behind. When ideling it produces approx 3.6 - 3.8 g/s and MAF requirement gauge always showing higher numbers 3.9-4.39. Ill post some screenshots and logs don't have much time working this weekend :/ I have added a screenshot of my maf running in idling is that normal? Also, noticed white smoke coming out of the exhaust pipe not much but its visible on sun. I accidently noticed it by looking at my side mirror when waiting for a green light. Anyone else expirince a problem with low mpg ? I had this from the moment when i installed downpipe but today it averaged down to 9.5 mpg for 47 miles drive that's kinda ridiculous and makes me think that i'm driving some kind of e63.

[///M248]

Originally Posted by vympel777

Okay i had performed a few tests also been monitoring my maf output and it looks like its running behind its requirement. fuel rail pressure seems to be stable no matter what high low rpms always meets the requirements and produce enough pressure. However now the Maf sensor always 0.4 - 0.5 behind. When ideling it produces approx 3.6 - 3.8 g/s and MAF requirement gauge always showing higher numbers 3.9-4.39. Ill post some screenshots and logs don't have much time working this weekend :/ I have added a screenshot of my maf running in idling is that normal? Also, noticed white smoke coming out of the exhaust pipe not much but its visible on sun. I accidently noticed it by looking at my side mirror when waiting for a green light. Anyone else expirince a problem with low mpg ? I had this from the moment when i installed downpipe but today it averaged down to 9.5 mpg for 47 miles drive that's kinda ridiculous and makes me think that i'm driving some kind of e63.

It's normal for actual values to be behind requested.

Smoke could be from a slight oil or coolant leak that was present before the DP install, that was made noticeable once the cat was removed.

Plugs and coils wouldn't be a bad idea especially if they haven't been replaced recently. New o2's should be done every 20k or so when tuned as well. All the above with reset adaptations should help mpg and cold start.

[vympel777]

Originally Posted by ///M248

It's normal for actual values to be behind requested.

Smoke could be from a slight oil or coolant leak that was present before the DP install, that was made noticeable once the cat was removed.

Plugs and coils wouldn't be a bad idea especially if they haven't been replaced recently. New o2's should be done every 20k or so when tuned as well. All the above with reset adaptations should help mpg and cold start.

Yeah, I guess ill start with maf cleaning and spark plugs. If that's not gonna work ill continue on replacing the injectors and o2 sensor both of these things are kinda pricey.
Any idea how much of Pft tq. I supposed to use when tighten down the spark plugs? and do i need a special tool in order to remove them?

[Logicoeur]

This weird start up issue happens a lot with aftermarket intakes with oiled filters, like the BMS.

Clean your maf, don't over oil the air filter or at least let it drydry before putting it back in and running the car.

Best option is to dump the BMS intake and run a dry filter like Pipercross or AFE. The stock box performs better than the open element filters like that, and you dont lose some torques down low. Punch some holes in the stock box if you want noise because that's all you actually get with an aftermarket intake.

[vympel777]

Originally Posted by Logicoeur

This weird start up issue happens a lot with aftermarket intakes with oiled filters, like the BMS.

Clean your maf, don't over oil the air filter or at least let it drydry before putting it back in and running the car.

Best option is to dump the BMS intake and run a dry filter like Pipercross or AFE. The stock box performs better than the open element filters like that, and you dont lose some torques down low. Punch some holes in the stock box if you want noise because that's all you actually get with an aftermarket intake.

That I didn't know. Will definitely try to jump back on my stock air filter.
Another thing I flashed my ECu back to stage 0 and now mpgs went up to 15 mpg. With MHD stage 2 I get 12 mpg max - which I had to drive like some kind of grandpa god forbid if I accelerate mpg would be going down to 9 mpg.
Many were saying that Stage 2 would not affect mpgs and it all depends on how hard you push it but it seems like the opposite.

I had several bmws and never had anything like this before even on my old e70 2012 with n54 was running solid at all times got over 95k miles on that car.

[vympel777]

Update did the spark plugs and cleaned my maf the car seemed much smoother but still had issues with little jumping rpms. Had to order new MAF sensor and vola the car runs new again.