Need help with intermittent codes/warm start issue

[whyzee125]

Hey guys,

I've been on e90post for 12 years but I'm relatively new here and this is my first time needing technical assistance. About 6 months ago, I started getting a random/intermittent 2ABD code on about 1 in 10 warm starts. No symptoms and if I'd clear it, the codes/reduced power mode wouldn't come back until a random warm start later. Then, on occasion, it started being accompanied by 2D2E.

It seemed like when the weather became less humid, they went away. I went a solid 3 months or so with zero codes and now that we're in the cold and rainy winter, they're back, seemingly about 8 in 10 starts, warm or cold. It's also become a little tough to control the throttle at very low RPMS, like parking lot speeds. It's pretty jerky and is affecting shift quality greatly. At anything above about 10% throttle, it drives completely normally and never sets any codes during driving.

Now here's the weird part. It seems like the exact time these codes got way more persistent, it's now developed a warm start issue. Cold, it cranks right up every time and when fully warmed up it cranks right up every time. But if you leave the car sitting for more than an hour or two, it has a very difficult time cranking and sometimes takes up to a minute or so, and is super rough requiring some throttle to keep it going. Once it smooths out and the codes are cleared, it's back to normal. I've viewed the MHD gauges one time when it wouldn't crank, and there are no fuel pressure issues (I initially suspected maybe an FPR issue).

Relevant info:
- 2009 335i 6AT w/ 112k miles
- Stock turbos
- Custom Wedge tune @21psi
- 3.5bar TMAP with BMS harness, confirmed secure and cleaning connections did not fix it
- Full e85 w/ MMP PI V2 (plate style with Genuine Bosch injectors, confirmed not leaking)
- ER CP with Tial BOV
- Stock valve cover, 1 year old with RB PCV
- BMS oil catch can

It does it on both pump gas and E85 tunes. The 3.5bar TMAP option is baked into my e85 tune but I used the setting in MHD when running pump gas. No change either way.

I've seen a fair amount of people with the same codes, intermittent like mine but I've seen very few answers. The car has had all existing mods since about 2018 and this is a new issue. I found one user who solved it by new intake manifold gaskets, one with a new throttle body, and many who have not solved it. Finally, @KnighTT had very similar symptoms and it was related to his PCV/OCC system but his was very heavily modified whereas mine's close to stock and the issue is new so I'm stumped.

Attached are some screenshots of the codes and a few datalogs as well. Any help is very appreciated!

Cold start NOT in limp mode (this was just before the codes began to return)

datazap.me | whyzee125 | E85 cold start

datazap.me

Cold start with both codes and in limp mode

datazap.me | whyzee125 | Cold start in limp mode

datazap.me

A normal 3-4 pull

datazap.me | whyzee125 | Another one

datazap.me

Thank you!

 

[carabuser]

I'm pretty certain both of those are related to the TMAP sensor.
2ABD is a plausability check of the ambient pressure sensor and the TMAP sensor. They should read the same when the engine is off, but that code means they are reading different values.

2D2E is a plausability check on the MAP reading which is the manifold sensor. This looks at the throttle angle and the TMAP to check if the MAP sensor is valid.

Either the scaling on the TMAP isn't set up right or the sensor is bad. Since you are only targeting 21PSI you are better to just use the original TMAP sensor anyway. If the problem goes away then you know that was the issue, otherwise you should check the MAP sensor out. Also add boost mean to the logs since that shows the TMAP sensor value.