[holmes011]

Hi so since I got my dci, DPs, and fmic installed on my 08 335xi I've been having a strange issue with my car. Under heavy acceleration the car will behave funny where it has a momentary lapse in power, it feels similar to having the traction control kick in, for a split second then the power comes on again. The car will also shift very roughly somewhat sporadically (again, under hard acceleration) in a way it never used to. I run a jb4 with this set up and prior to all these installs I had my jb4 running for over a year without any problems. I've taken it back to the place that did it and they checked to make sure it wasn't a boost leak or anything and everything was sound in that respect. I've also looked to see if it was the turbos and they seem to be fine as well (the car only has 43k miles). I've searched the forums to see if other people have had similar issues and there have been shifting issues but they varied from what I have been experiencing. I'm really at a loss here and don't want to blindly throw cash to try to figure this out and was hoping people on here could help. Thanks guys

[litxus]

Originally Posted by holmes011

Hi so since I got my dci, DPs, and fmic installed on my 08 335xi I've been having a strange issue with my car. Under heavy acceleration the car will behave funny where it has a momentary lapse in power, it feels similar to having the traction control kick in, for a split second then the power comes on again. The car will also shift very roughly somewhat sporadically (again, under hard acceleration) in a way it never used to. I run a jb4 with this set up and prior to all these installs I had my jb4 running for over a year without any problems. I've taken it back to the place that did it and they checked to make sure it wasn't a boost leak or anything and everything was sound in that respect. I've also looked to see if it was the turbos and they seem to be fine as well (the car only has 43k miles). I've searched the forums to see if other people have had similar issues and there have been shifting issues but they varied from what I have been experiencing. I'm really at a loss here and don't want to blindly throw cash to try to figure this out and was hoping people on here could help. Thanks guys

When was the last you replaced spark plugs?

[Zach1328]

Originally Posted by litxus

When was the last you replaced spark plugs?

+1. Any codes?
The main 3 things that cause issues like that are Coils, Plugs, or Injectors. Your VANOS solenoid may need cleaning too.

[mike@x-ph.com]

Check for codes and post a few logs from 2500 to redline third gear.

[holmes011]

Originally Posted by mike@x-ph.com

Check for codes and post a few logs from 2500 to redline third gear.

I don't have the ability to get logs and it is not throwing any codes except for the o2 sensor because of my DPs

[holmes011]

Originally Posted by Zach1328

+1. Any codes?
The main 3 things that cause issues like that are Coils, Plugs, or Injectors. Your VANOS solenoid may need cleaning too.

I haven't checked these things but I'm not sure if these things are the problem since everything was fine running map one before the additional mods. And now whether I run map 1, 2, or 5 the problems are present although they seem to be more noticeable in 2 and 5. It's also worth noting that I've turned the tune off a few times and accelerated hard a few times and the car did not seem to have these issues

[j1gilles]

Originally Posted by holmes011

Hi so since I got my dci, DPs, and fmic installed on my 08 335xi I've been having a strange issue with my car. Under heavy acceleration the car will behave funny where it has a momentary lapse in power, it feels similar to having the traction control kick in, for a split second then the power comes on again. The car will also shift very roughly somewhat sporadically (again, under hard acceleration) in a way it never used to. I run a jb4 with this set up and prior to all these installs I had my jb4 running for over a year without any problems. I've taken it back to the place that did it and they checked to make sure it wasn't a boost leak or anything and everything was sound in that respect. I've also looked to see if it was the turbos and they seem to be fine as well (the car only has 43k miles). I've searched the forums to see if other people have had similar issues and there have been shifting issues but they varied from what I have been experiencing. I'm really at a loss here and don't want to blindly throw cash to try to figure this out and was hoping people on here could help. Thanks guys

When is the last time you updated your firmware?

[335NJ]

Have you confirmed the only code being thrown is for the o2 sensor?

[holmes011]

Originally Posted by j1gilles

When is the last time you updated your firmware?

It's never been updated and I don't think I can because I have the old g4 or because I have not cut the diodes. I believe one, if not both, of those are reasons why I can't update. for some reason I have the g4 even though I bought it new last summer so I think I should have received a g5 but I'm not entirely sure.

And Im positive about the o2 sensor being the only code

[4doorbmwpower]

Originally Posted by holmes011

I haven't checked these things but I'm not sure if these things are the problem since everything was fine running map one before the additional mods. And now whether I run map 1, 2, or 5 the problems are present although they seem to be more noticeable in 2 and 5. It's also worth noting that I've turned the tune off a few times and accelerated hard a few times and the car did not seem to have these issues

you can flip it to map 0 and the car run perfectly fine and in map 5 it can get NASTY missfires and have those issues because the car demands 110% from everything when its pushing it like that, when your at say 60% and stock the car can seem perfectly fine. I would ensure the same problems dont persist when you have it on map 0. if they go away i would do the good ol catch all for these kinda problems and do sparks see if its fixed then trace to coils, likely it isnt injectors but there are notable problems with this platform.

[335scott]

holmes011, I know exactly what you're talking about. The same thing happens to me as well, the feeling of a lapse of power/traction control. Its just not a smooth acceleration like it normally is.

[Zach1328]

Originally Posted by holmes011

I haven't checked these things but I'm not sure if these things are the problem since everything was fine running map one before the additional mods. And now whether I run map 1, 2, or 5 the problems are present although they seem to be more noticeable in 2 and 5. It's also worth noting that I've turned the tune off a few times and accelerated hard a few times and the car did not seem to have these issues

The plugs, coils, or injectors are most likely the issue if its fine with the tune off. Sometimes the plug is strong enough to make a large enough spark for 300hp but as soon as you've got 450hp a weak spark plug, coil, or injector can't fuel the cylinder enough or can't burn all of the gas.

When I first installed my JB4 I was getting a cylinder 1 misfire. The issue was present on all maps and went away immediately when I turned my JB4 to map 0. My issue was solved by changing the plugs. Now I have that annoying rough idle so I need to tackle that now.

[j1gilles]

Any transmission codes?

[bfoolish1339]

Originally Posted by holmes011

Hi so since I got my dci, DPs, and fmic installed on my 08 335xi I've been having a strange issue with my car. Under heavy acceleration the car will behave funny where it has a momentary lapse in power, it feels similar to having the traction control kick in, for a split second then the power comes on again. The car will also shift very roughly somewhat sporadically (again, under hard acceleration) in a way it never used to. I run a jb4 with this set up and prior to all these installs I had my jb4 running for over a year without any problems. I've taken it back to the place that did it and they checked to make sure it wasn't a boost leak or anything and everything was sound in that respect. I've also looked to see if it was the turbos and they seem to be fine as well (the car only has 43k miles). I've searched the forums to see if other people have had similar issues and there have been shifting issues but they varied from what I have been experiencing. I'm really at a loss here and don't want to blindly throw cash to try to figure this out and was hoping people on here could help. Thanks guys

I've had the same problem for about a year now. Not the spark plugs because I had it before and after my last covered service and they changed my plugs.

I've even sent the box in to bms to check it out ... Eventually upgraded to a G5. I still have the issue every once in a while #shrug