S54 Delayed Throttle Response from Idle

[wyshyvanuk]

I’ve now read through over 250 posts (no joke), here and on the Z4-forum, that attempt to address the problem of a delayed throttle response, from idle, on S54 engines. The following is a not-necessarily-definitive list of parts or issues that may be causing the problem:

1. Replace the TPSs (throttle position sensors) on the engine front (already replaced) and under the intake manifold.
2. Check and/or replace the throttle in the cabin. There’s a position sensor in there, as well.
3. Clean and/or replace the Idle Control Valve.
4. Replace/rebuild the Throttle Actuator ($$$).
5. And a bunch more.

A number of the posts also reported that, in addition to the delayed throttle response (from idle), if a couple of healthy throttle blips were applied closely together, a backfire through the intake manifold could be heard. I have that, as well.
Has anyone successfully cleared this annoying problem? Any advice? Thanks in advance!!
Ted

[Steeler]

Originally Posted by wyshyvanuk

I’ve now read through over 250 posts (no joke), here and on the Z4-forum, that attempt to address the problem of a delayed throttle response, from idle, on S54 engines. The following is a not-necessarily-definitive list of parts or issues that may be causing the problem:

1. Replace the TPSs (throttle position sensors) on the engine front (already replaced) and under the intake manifold.
2. Check and/or replace the throttle in the cabin. There’s a position sensor in there, as well.
3. Clean and/or replace the Idle Control Valve.
4. Replace/rebuild the Throttle Actuator ($$$).
5. And a bunch more.

A number of the posts also reported that, in addition to the delayed throttle response (from idle), if a couple of healthy throttle blips were applied closely together, a backfire through the intake manifold could be heard. I have that, as well.
Has anyone successfully cleared this annoying problem? Any advice? Thanks in advance!!
Ted

Any fault codes?

[wyshyvanuk]

No fault codes as of a few weeks ago, but I'll check again today. Thanks!!

[maupineda]

I have no such issue, software update maybe a thing too, try to update to the latest BMW software

[wyshyvanuk]

No codes at all.
In the interest of full disclosure, the engine has a G-Power supercharger installed, with a DME flash from those fun-loving folks in Bavaria.
I was able to view the action of the throttle actuator as I blipped the throttle. Virtually instantaneous transmission of the throttle input. Probably means little to nothing in terms of diagnosis, but it makes me lean toward replacing that TPS under the manifold.
Thanks, guys!! More advice is welcomed.

[Steeler]

Originally Posted by wyshyvanuk

No codes at all.
In the interest of full disclosure, the engine has a G-Power supercharger installed, with a DME flash from those fun-loving folks in Bavaria.
I was able to view the action of the throttle actuator as I blipped the throttle. Virtually instantaneous transmission of the throttle input. Probably means little to nothing in terms of diagnosis, but it makes me lean toward replacing that TPS under the manifold.
Thanks, guys!! More advice is welcomed.

Surprised the backfiring hasn't caused an error code.
A lean or rich mixture will cause backfiring.

Regardless of the issues you are having now, I would highly recommend a tune from pokeybritches
Likely kill 2 birds with one stone.
You are also likely leaving a lot of power on the table.

[wyshyvanuk]

I've had a number of PMs with Josh at the beginning of this SC adventure. Knowledgable and helpful!!
Judging from the number of posters with this throttle response issue, I really believe it's a hardware, rather than a software, problem. I'd like to pursue that possibility before I modify the tune.
Thank you, sir!!