E46 328i auto throttle cable issues

[LLC24]

Recently had a new cable fitted and after fitting the car felt sluggish/slower and less eager to rev. Then had the cable tightened and it was okay for a day or two and then lost power again.
I took it to a bmw dealership after this and they said their technician didn’t know how to do the throttle cable on this car because of its age and they “haven’t seen one in a long time” which sounded ridiculous to me as surely a bmw technician should be able to figure it out but oh well. They said they thought it may be routed wrong which I later found it was after taking it to a specialist.
So now the specialist has routed it correctly, I now still have no power or kickdown. Last night I had a go myself at sorting it. I adjusted it wrong at first making the issue worse but then sorted it out again. However the cable seems to be at the end of its adjustment and I still have noticeably less power and no kickdown.

Any help/advice on sorting this would be greatly appreciated as I’m sick of the car feeling like my old 318i instead of how it should be.

[d_a_n1979]

Are you sure it's the cable and not an issue with the TB?

What about vac leaks etc; have you checked all the intake boot piping from MAF to TB to see if there are any splits, letting in air after the MAF?

[helix402]

There was a very similar thread to this recently. The new cable needs setting up with diagnosis software. There is a set value which should be reached at full throttle, the M52tu is a bit odd as it has a throttle cable and a throttle motor working in tandem.

I have an old thread on my old 328i which may explain more.

[LLC24]

d_a_n1979 said:

Are you sure it's the cable and not an issue with the TB?

What about vac leaks etc; have you checked all the intake boot piping from MAF to TB to see if there are any splits, letting in air after the MAF?

I only started having this issue after the cable was replaced. The MAF & intake boots are fine still. I had those off last night so I could see the throttle body move. The throttle valve isn’t opening fully & no matter how I adjust it, it doesn’t seem to open more than a quarter of the way or so.

[LLC24]

helix402 said:

There was a very similar thread to this recently. The new cable needs setting up with diagnosis software. There is a set value which should be reached at full throttle, the M52tu is a bit odd as it has a throttle cable and a throttle motor working in tandem.

I have an old thread on my old 328i which may explain more.

Okay thank you. Is this something a bmw dealership should be able to do then?

[helix402]

LLC24 said:

Okay thank you. Is this something a bmw dealership should be able to do then?

As you mentioned, sadly it depends on the experience of the techs at the dealer in question. Yes, they should. You may be better with an older ex main dealer Indy who worked on the E46 when it was new.

[Touring442]

LLC24 said:

I only started having this issue after the cable was replaced. The MAF & intake boots are fine still. I had those off last night so I could see the throttle body move. The throttle valve isn’t opening fully & no matter how I adjust it, it doesn’t seem to open more than a quarter of the way or so.

Remove the throttle body (four 10mm bolts, the screw connector and some other stuff) and give it a good clean out. The idea behind these is that the big motor on the side can close the throttle disc when the ASC system detects wheelspin, even ig the pedal is depressed. I suspect the TB is gummed up preventing the disc from fully opening - hold the disc shut with your finger and the throttle quadrant will still move as normal. You may well require another TB if yours won't play ball - you should have a blue label unit with the part number ending in 414. Z3's and some others used a yellow label unit.

I've never had to fart about with diagnostics when replacing the cable on an M52TU.