[IKON12]

I have been having problems lately with my 2007 335i 6mt. I bought the car in march with the afe dual cone intake, Eisenmann race exhaust, and jb4 already installed.

Driving the car home from California I felt a very slight "hesitation" when accelerating in sixth gear at high speed (120+). I didn't think anything of it.

We drove the car for a few months before I was able to go push it again. At this point I was going into reduced power mode when the jb4 was on map 1 or map 5, on map 0 it would run out all the way to 155, however the hesitation was getting worse. It felt like the boost was varying.

I spoke to bms and they had me change the open loop fuel number to 70 and then 60 which I thought fixed the problem, but a few months later I experienced the same reduced power mode when pushing it hard at high speed. The hesitation was getting worse and I was starting to hear the wastegates rattling.

I hooked up the computer and did a few logs and sure enough, the boost was "wavering" about a half a psi.

Since I have an aftermarket warranty I took it to the dealer to have them look into the wastegate rattle. They replaced the turbos but called me and said that the problem got worse with the new turbos.

I went and drove the car and it is 100% worse. It hesitates very badly now on the stock map and bucks on map one, once you reach ~3000 rpm it feels like the engine shuts off and comes back on.

The dealer is convinced that the aftermarket intake is causing the problem but I don't buy it. Has anyone heard of an aftermarket intake causing these symptoms?

The second thing is the tech said he hooked up a boost gauge and was getting 12psi on map 0. He said all of the cars he has worked on are running 9.

I put it on map 1 and was getting 16 psi (According to the hijacked fuel gauge).

These number seem 2-3 psi higher than they should be. What would be causing the car to run higher boost even on the stock map..

Last, they gave me a 2012 335i as a loaner And I noticed that I could hear the diverter valves on it. The diverter valves on my car do not make any noise at all. Is it possible that the diverter valves are stuck closed? It also feels faster than my car.

The Hpfp was replaced about a year ago And I am not getting any codes.

I am stumped. Please advise!

[jwalker87]

I may just be saying this because it's on my mind, but maybe the intake valves are gunked up? How many miles are on the car? I'm having an issue of stumbling at WOT and high rpms, and think it may be partially due to this. I just cleaned them, but will have to wait to test out my theory until Thursday.

[IKON12]

It has 75000 on it. Did you remove them to clean them? Please update on the determination of whether it helped or not.

[uniter]

Remove the tune and see if any codes pop up. Plugged DVs would throw an 'overboost' or 'throttlebody position airmass plausibility' code fairly quickly. Your aftermarket intake isn't causing the issues, but a dealer will blame any aftermarket part in the plumbing for any issues.

I had a dealer blame my forge DV's for symptoms of a broken clutch.

[IKON12]

Should I completely remove the jb4 or will pass through be sufficient?

[uniter]

Not sure if the JB4 will fudge it up. Sink the time into removing it, you'll only get better at R&R

[Randomaccess335]

If taking to a dealer..... Completely remove every time
Map 0 will will be fine if looking for issues not related to tune....

I went to a local shop while back, there computer couldn't connect while jb4 connected

[Gugs]

Originally Posted by Randomaccess335

If taking to a dealer..... Completely remove every time
Map 0 will will be fine if looking for issues not related to tune....

I went to a local shop while back, there computer couldn't connect while jb4 connected

Cause the jb4 takes over the obd port when on. :
Turn to 0 and you can read the car.
I've had my car updated at BMW with jb4 on map 0.

[boostaholic786]

I have too. Make sure you either take the JB4 completely out if your problem is related to any sort of DME issues. Otherwise set it to map 0 and the BMW computer can read your car as if you didnt even have a tune.

[enrita]

Did you switch off auto code clearing? Could be a sticky wastegate but than you would get overboost code and limp. Remove jb4 and see how car runs than check how jb4 works on n54tech

[Blackhawk36]

You have dirty intake valves. Take off your intake manifold and look at them or remove the sensor on the rear/top of the intake and send a borescope through to look at it.

[IKON12]

I went through there today and told them I want the car back.

Surprisingly enough it does feel better with the stock intake but it does not sound good at all.

The problem seems to be worse when the car is not up to full operating temperature.

Auto code clearing is off and I just got brand new turbos so I can't blame the waste gate.

Am going to change the plugs and make sure I have all 261 injectors and get some logs into BMS. I will clean the intake valves asap. It is just very odd to me that it is boosting 12psi on the stock map.