[damonp335i]

Hey so I just picked up my car. I love it and it runs great 99% of the time. The other 1% is when it has the hesitation at WOT in 3rd gear and up. I watch the boost drop from 14.0 to 13.5 and back to 14 then back to 13.5 all the way up to near redline.. Now it hadn't had this issue in a few days and then randomly last night was doing it quite a bit.. then this morning and today back to normal. Could this be an issue with the tune? I assume if anything was mechanically incorrect this problem would occur all the time.. no?

Thoughts and opinions appreciated - TY in advance

EDIT: As a precautionary measure I plan to get the walnut blast done and some new plugs. Car only has 32k miles, but has been sitting for months at a time over the last 4 years (rarely driven). Do you think its too soon to do the walnut blast and I should wait? or just get it done regardless.

EDIT x2: I've spoken to a few people about this issue because I noticed it when I test drove the car but after the original owner got rid of the gas that had been sitting in it for months and started fresh with some new 93, the car ran beautifully so I assumed the problem had to do with stale gas. I've driven it for a week with no issue until the little bit last night, then today its back to normal. I assumed maybe the weather changing at first, but its been colder then it was last night and still ran fine. My local BMW dealership no longer deals with DINAN so I cant get the tune updated that easily, and I've been told to ditch the DINAN tune for MHD or COBB regardless because DINAN sucks (allegedly). Basically I wanted to wait for more bolt ons before I went to a new tuner but if it is the tune causing this it definitely needs to go ASAP.

[Antetokounmpo]

Are the spark plugs original? If so, change them. If not, change them.

[damonp335i]

Originally Posted by bk335

Are the spark plugs original? If so, change them. If not, change them.

LOL will do. What brand/gap is recommended?

[Antetokounmpo]

Originally Posted by damonp335i

LOL will do. What brand/gap is recommended?

OEM bosch will be ok, they're pregapped. NGK 5992 gapped to .022'' are better for tuned cars however. If don't plan to go back to stock, the NGK are the way to go.

[damonp335i]

Originally Posted by bk335

OEM bosch will be ok, they're pregapped. NGK 5992 gapped to .022'' are better for tuned cars however. If don't plan to go back to stock, the NGK are the way to go.

Yeah not really planning on going back to stock.. only more HP from here on out. Thank you sir

[damonp335i]

You think the plugs are overkill because I'm only running 14psi

[Jeff@TopGearSolutions]

Dinan is a good tune but it's conservative and you can get more power out of other tunes for considerbly less money.

That being said, change your spark plugs and go from there. If they have over 25,000 miles on them they should be changed on any tuned vehicle.

Bosch OEM or NGK are recommended.

[Antetokounmpo]

Originally Posted by damonp335i

You think the plugs are overkill because I'm only running 14psi

Like I said, OEM Bosch will be adequate. I'm still running OEM bosch plugs on 18psi. But NGK will be better, if you ever upgraded to jb4/mhd down the road they'll be even better too.

[damonp335i]

Originally Posted by Jeff@TopGearSolutions

Dinan is a good tune but it's conservative and you can get more power out of other tunes for considerbly less money.

That being said, change your spark plugs and go from there. If they have over 25,000 miles on them they should be changed on any tuned vehicle.

Bosch OEM or NGK are recommended.

Okay thanks. I am going to change them today. I just want to make sure that if I go with the NGK 5992's gapped to .022 that I'm not going to have a rough idle or whatever, but I also don't want to replace them with the OEM onces and have the same issue im having now.

[fredcase]

My dinan tune used to do this also, it had brand new plugs, coils and injectors and still did it. It got progressively worse, and a walnut blast eliminated it.

I have since gone jb4 with backend flash and honestly miss my dinan tune. If I had to do it again, I would have kept the dinan, added a fmic, an cold air intake, and exhaust. Would be a little less power than I have now but much more consistent, reliable and smooth.

[damonp335i]

Originally Posted by fredcase

My dinan tune used to do this also, it had brand new plugs, coils and injectors and still did it. It got progressively worse, and a walnut blast eliminated it.

I have since gone jb4 with backend flash and honestly miss my dinan tune. If I had to do it again, I would have kept the dinan, added a fmic, an cold air intake, and exhaust. Would be a little less power than I have now but much more consistent, reliable and smooth.

Can you run jb4 + dinan? and also 32k too soon for walnut blast?

[Antetokounmpo]

Originally Posted by fredcase

My dinan tune used to do this also, it had brand new plugs, coils and injectors and still did it. It got progressively worse, and a walnut blast eliminated it.

I have since gone jb4 with backend flash and honestly miss my dinan tune. If I had to do it again, I would have kept the dinan, added a fmic, an cold air intake, and exhaust. Would be a little less power than I have now but much more consistent, reliable and smooth.

He likely wouldn't be experiencing those problems from carbon buildup since he only has 32k miles.

[88atlas07]

I hope you find the cause of this issue because I have the Dinan stg 3 tune and experience the same thing and cant figure it out. Ive gone through the whole list of part replacements...plugs, coils, injectors, walnut blasting, vac lines, adaptation resets etc and it still does it.

I read somewhere that this boost oscillation is the throttle plate opening and closing to control boost. Not sure how true that is but Ive come to live with it for the time being. It comes and goes, some weeks it runs great, other weeks it hesitates.

[Brule]

Flash tuning is more consistent, smooth.
Cobb or MHD will give you the same consistent throttle.

[bmwmsport]

Originally Posted by damonp335i

Can you run jb4 + dinan? and also 32k too soon for walnut blast?

I think JB4 will delete the Dinan tune. I know Cobb or MHD will.

[fredcase]

Jb4 is a piggy back, dinan is a flash, so jb4 will ride the dinan, but not well.

I tried this and would get 30ff low boost codes, and spent a tonne of time and money chasing a boost or vacuum leak that didn't exist. 30ff was because dinans timing and afr is not safe for anything over 14psi. I reflashed with a bms backend via mhd and now I hold 17psi well.

My dinan was very sensitive to gas octane before walnut blast. That sputter in a high load low throttle situation turned into a misfire with poor gas. Canadian gas sucks and my elevation is very high.

[gtaccord]

Dinan tune does suck. If you search around there are a bunch of threads about the os illusion issue which they never solved. My car had dinan Stg 2 when I bought it. I ditched it for cobb and never looked back.

[Jeff@TopGearSolutions]

Originally Posted by damonp335i

Okay thanks. I am going to change them today. I just want to make sure that if I go with the NGK 5992's gapped to .022 that I'm not going to have a rough idle or whatever, but I also don't want to replace them with the OEM onces and have the same issue im having now.

Unfortunately every car responds differently. IT also depends on how recently your intake valves have been cleaned and how well your PCV system is flowing when it comes to idle on these cars. Injectors are another factor.

Most people we know experience no issues with the NGK. For those that might, they may have other issues that haven't been corrected yet.

Originally Posted by damonp335i

Can you run jb4 + dinan? and also 32k too soon for walnut blast?

You can't stock Jb4 and Dinan. The dinan needs to be removed.

Jb4 will not delete the Dinan.

Dinan is a flash tune, only another flash tune can remove it.

[damonp335i]

Thanks everyone for the replies. I wasn't able to get to my computer until now. Sounds like the oscillation issue is probably tune related? I know someone mentioned that it could be related to the throttle plates.. But alot of people said that a flash tune fixed the problem. I am just afraid to flash MHD or Cobb and regret it and wish i could go back to the DINAN. I want to replace plugs and get walnut blast regardless, so im going to start there. Ill keep you guys updated.

[dlbrooks18]

If you have access to a BT tool, try resetting adaptations. If you don't, I would invest in one. You need to see if car has thrown any codes to help troubleshoot. I think also the bmwhats app may have this feature now too.

[damonp335i]

I used the scanner and there are no pending codes or active codes

[dlbrooks18]

Here is an old thread about resetting adaptations:

http://www.e90post.com/forums/showthread.php?t=386376