[Neepamonsteri]

Hello folks, a quite fresh BMW owner here (coming from a looong VAG past).
I've had my 114i for half a year now and tweaked it here and there.

Problem:
One thing I haven't been able to sort out is the huge throttle delay on first gear. Basically if you push pedal to the floor on any rpms, car waits a full second or even more before anything happens. This is totally new for me. It happens only on first gear, there is virtually no delay on 2 and 3 gear for example. And to be clear, we are not talking about turbo lag nor throttle pedal curve/mapping. This issue takes all the fun out of driving, car feels totally sluggish and unresponsive on the gear you use the most.

What's been done:
I've searched through different forums and found nothing but turbo lag and progressive vs linear throttle pedal mapping discussions.
The problem is the same as stock and mapped to stage1. I've had 2 different tuners to look into it, but neither of them have found a way around it.
I've also asked BMW dealer on two different occasions about this and they've "mumbled" around "it is designed that way", but no one has been able to give any actual reason why it is there and how it is implemented. I bet guys at the dealer didn't really know why and weren't really interested to look into it further.

Illustration:
I've taken some logs which perfectly show the issue. As you can see in the picture; accelerator pedal is pushed all the way to the 100% and throttle plate doesn't move at all. After a full second or so it finally opens fully. On second and third gear throttle plate moves instantly with accelerator pedal without delay.



So, where the real knowledge lies, the almighty forums and its users, hope you can help me! What's your experience and thoughts on this?


car specs:
-114i year 2013
-manual trans
-N13 engine

[IJO]

Maf & pre cat sensors should be changed at 150k kms or less if the performance and fuel consumption are not right.

10year old sensors are expected to be out of spec.

If the maf signal is a bit weak, this will underfuel the engine when you set off and the turbo has not spooled up. This also delays the spooling up.

It doesn't happen in other gears because you are not starting from zero speed and idle rpm.

[Neepamonsteri]

Thanks for the reply IJO,

Just to add, I am not starting from the stand still or idle rpms. The same thing happens when running 30km/h and starting rpms over 3k. Actually the starting rpms on the graph is 3300 (just checked). Should've added that to the graph, sorry.

Car has run 95000km. I don't know if the MAF or pre cat sensors have ever been changed. Do you still think these might cause such things (considering I wasn't starting from standstill or idle rpms?)

[IJO]

No one can know for sure whether changing them will be a cure but it's quite reasonable after 10years to think they could be involved.

I changed both on my 150k 2014 116i mainly due to poor fuel consumption (very sooty tailpipe) as they are not too costly and easy to do. (you do need a low cost O2 sensor removal tool).

Just remember to buy well known brands such as Bosch, not cheap unbranded ones.

The other part you may need change is the hose that connects the maf sensor housing to the turbo inlet. Mine had split where it attaches to the turbo so air was bypassing the maf. (causing a weak signal and poor throttle response when setting off)

This could also explain your issues and a replacement is not expensive.
Check if first before buying the sensors.

[Neepamonsteri]

I'll have a look at the hose and find out prices for the sensors. Actually, the car has kind of sooty tailpipe.

About to fix the wastegate rattle so changing the pre cat sensor wouldn't cause much more work.

Is your car manual or auto? Do you experience this delay if you floor the car on first gear (any rpm but preferably around 3k)?

[IJO]

Originally Posted by Neepamonsteri

I'll have a look at the hose and find out prices for the sensors. Actually, the car has kind of sooty tailpipe.

About to fix the wastegate rattle so changing the pre cat sensor wouldn't cause much more work.

Is your car manual or auto? Do you experience this delay if you floor the car on first gear (any rpm but preferably around 3k)?

Mine is manual and since changing those two sensors, the tailpipe has no soot inside or out.

I don't have any hesitations at any rpm in any gear but the only time I did have one when setting off, was when there was a pre maf air leak. (the intake duct and later from a poor joint to my oil catch tank which connects to the larger pipe joining the above intake duct.)

I recommend removing the duct because the split in mine was on the underside so I didn't see it initially.