[stibz]

Hello all,

Looking for some help with my 2009 335d: ABC delete, JR 2.8 Tune, 155k miles. Stock turbos, bigger intercooler, ATM intake. It's been tuned since roughly 80,000 miles and I've had zero issues, this thing has been flawless until now, and I drive it very hard.

A few months back I'm driving up my street and it feels like its pulling a bit harder than normal and I'm hardly on the go pedal as I leave my house. It does it again as I leave a stop sign gently and it goes into limp mode. It continues to do this somewhat intermittently, as it will go out of limp mode, feel normal, and then back into limp mode. No excessive smoke. No funny noises.

Codes:
4C83 (exhaust pressure upstream of turbine, plausibility)
3F25 (Charge air hose monitoring)

Vacuum is good. Vac hoses are good and have been replaced. Vac pressure converters tested good but I replaced them anyway. And the following has been replaced; MAP, MAF, exhaust gas pressure sensor and hose, vac control valve. I also reflashed the ECU with the updated JR 2.8 tune. No boost leaks. Turbo actuator moves freely, full range, and holds vac. Adaptations were reset after replacement of the various sensors.

I'm beginning to think maybe the small turbo is failing. Seeing if anyone has any other ideas before I pull the turbo's and send them for rebuilds. Thanks in advance! I'm in Sarasota county Florida if anybody local can help.

Rob

[Andystobbs]

Have you actually removed the pipe connecting the exhaust pressure sensor to the exhaust system?

[stibz]

Yes, I replaced the hard pipe and the hose going to the sensor nipple. When I removed the old sensor, the nipple was completely clogged with soot, so I was confident that was gonna be the fix....replaced it, along with hose and hard line, adaptations reset...but same issues.

[robnitro]

If the turbo was failing, the only way it could cause this is by leaking oil into the engine, creating extra fueling.

Do you have high oil consumption?


If it was just extra boost, extra air, diesels fuel by pedal position, not by airflow like in gas engines.

The codes could be from overfueling of the oil, like let's say there's a pool of oil in the intercooler that slugs it's way in. The ECU doesn't know of the extra fueling and thinks the boost is implausible based on the fuel it's giving.

How's your injector balance numbers BTW?

[lnxguy]

155K miles, vac pump leaking? If it's not I'd be very surprised. They also tend to wear out, at that mileage I'd pop a new Hella unit in instead of just replacing seals.