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.

 

[whyzee125]

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.

Thank you very much, @carabuser . I will enable boost mean and see where that gets me. I should have the stock TMAP sensor too so that would be an easy way to rule that out. Car has been parked this week but I'll dive into it this weekend and report back if I'm successful!

 

[ktb_e92]

Have you brought this up to Wedge? No shame intended towards Wedge at all, but throttle mapping seems to not be an uncommon issue that recurs when running their custom tune based off of several sources I've read through, along with seeing multiple friends in-person deal with it too. Their cars will either have fluctuating idle and/or stalling after the first few minutes post-cold startup, and sometimes post-warm start along with that throttle angle code.

I've personally dealt with it, but only once, and I'm not tuned by Wedge. It would idle weird upon startup and at its worst point it'd idle like a big-cam V8 until I shut the car off, cleared codes, then restart it. This was months ago, and has yet to come back because when it was happening, my tuner requested a normal driving log so he could most likely revise some of the throttle settings before sending a new file back to me. Keep us updated

 

[whyzee125]

I actually haven't; while I thought it was tune related at first, it does it on OTS maps, my 93 map, and my e85 map. I did make some progress though--I'll post below!

 

[whyzee125]

I enabled boost mean in MHD and logged another cold start. It looked like the boost mean didn't record anything for a while, making me think it's a bad sensor or a bad connection? I watched the gauges for a while and it had a little flicker of a reading twice. I cleared the codes and then it was reading after that.

Here's a cold start log (in limp mode) and then a normal pull log after clearing it.

Cold start: https://datazap.me/u/whyzee125/e85-cold-start-w-boost-mean

Pull: https://datazap.me/u/whyzee125/pull-after-clearing-2abd?log=0&data=3-20

 

[ktb_e92]

Weird how your boost mean wasn't reading at first. That could indicate a possible issue with your MAP sensor which could explain your car acting up occasionally, I doubt it's your TMAP. I've never had any issues with the same TMAP kit that you have.

And okay, if you haven't contacted Wedge I'd do that as soon as possible because you can only troubleshoot so much, especially throttle-wise, before they need to be involved. This is because they're the tuner and have lots of access to the parameters, within the throttle system, that you don't have. Keep us updated

 

[whyzee125]

I appreciate the reply but this shows it's definitely not tune related. I've been running the same tune since 2018 with zero issues until 6 months ago and it also does it with MHD un installed.

The fact that the TMAP is reading intermittently seems to definitively show that it's either a TMAP connection issue or the sensor itself going bad. I'm out of town now but I'll dig into it next weekend and keep you all posted!

 

[ktb_e92]

No problem, sounds good