stuttering\bogging 2011 335i

**Erzenble** · 05-12-2019, 07:43 AM

Hey guys I am having a problem I really need to narrow down. I have spent the last few months researching trying to figure this out. So hopefully someone can shed some light.

I have a 2011 335i stock except for a bms intake. Plugs and coil packs changed 6 months ago. Airfilter and MAF sensor just cleaned.
No codes stored or codes shown through carly diagnostics

The problem I'm having is when I push the car at all it starts to bog and shutter like it's flooded then eventually takes off at higher rpm. It's not smooth acceleration at all. This seems to happen when its in higher gears and a lot worse at lower rpms 2-4k. If I WOT It is smooth but just slow. It has lost a lot of power in the last few months and is getting worse. The car has lost all pep at lower acceleration. If I take off from a stoplight I have to eas into it or the car jerks then takes off.

I have logged through torque pros realtime charts addon and my hpfp is at 2100-2300psi through out WOT. Boost gets up to 10psi.

From what I have read possible causes could be injectors, hpfp, VANOS. Hopefully somebody has had these exact symptoms before to narrow it down.

Also I dont see an option to add an image, maybe im missing it?

**MarcoZandrini** · 05-12-2019, 09:43 AM

Is the fuel pressure consistent through out the rpm range and under various loads? Same question for the boost level.

**Erzenble** · 05-12-2019, 10:59 AM

At idle its at 700psi steady and anywhere up to 2400 at wot. The boost looked good at wot but I dont think I'm making much boost under 3k. I'm not sure how much boost I should have that low of rpm

**Erzenble** · 05-12-2019, 11:06 AM

Originally Posted by MarcoZandrini

Is the fuel pressure consistent through out the rpm range and under various loads? Same question for the boost level.

Actually now that I looked again during the run my rail pressure went from 2500 steadily down to 2150. I'm not sure if thats low or not

**White94RX** · 05-13-2019, 07:53 AM

Have you checked your intake ports for carbon buildup? They get super nasty and have to be walnut blasted.

**Erzenble** · 05-13-2019, 09:09 AM

Originally Posted by White94RX

Have you checked your intake ports for carbon buildup? They get super nasty and have to be walnut blasted.

I havent actually. Would some carbon build up really make a 335i run that bad though? I do use chevron techron fuel system cleaner once in a while.

**White94RX** · 05-13-2019, 09:15 AM

I've felt them stutter and lack power. If yours are really bad, it could be possible. It's worth checking. If it's never been done, I'm sure it needs it anyway. How many miles on the car?

**pbonsalb** · 05-13-2019, 02:31 PM

You would not believe how much goo builds up in the intake ports. Scrap it out and blast the carbon after that. Buy a copy of the special tool that adapts to an intake port and use a cheap blaster and shop vac and walnut shell mix. You can find the details with some searching.

**Erzenble** · 05-14-2019, 01:35 AM

Originally Posted by White94RX

I've felt them stutter and lack power. If yours are really bad, it could be possible. It's worth checking. If it's never been done, I'm sure it needs it anyway. How many miles on the car?

110k. I don't think its been done but I bought the car at 100k so I'm not sure.

- - - Updated - - -

Originally Posted by pbonsalb

You would not believe how much goo builds up in the intake ports. Scrap it out and blast the carbon after that. Buy a copy of the special tool that adapts to an intake port and use a cheap blaster and shop vac and walnut shell mix. You can find the details with some searching.

Ya I looked at a video on how to do it. Looks like a big job. How often should it be done?