Z4 2.5 tick over issue

[Paintermark9]

Hello all, I have just purchased my first 2004 z4 2.5, I was trying to get some advice regarding the tick over issue it has, if I press the footbrake the revs increase, take it off and its back to normal tick over, any thoughts on what it could be.
Thanks

[enuff_zed]

Hello all, I have just purchased my first 2004 z4 2.5, I was trying to get some advice regarding the tick over issue it has, if I press the footbrake the revs increase, take it off and its back to normal tick over, any thoughts on what it could be.
Thanks

Welcome to the forum.
Is this a pre-facelift M54 or a facelift N52 engine?
Purely for future reference tbh, as the cause of your problem is most likely to be an air leak. Check the connections and condition of the pipe that runs from the brake servo to the manifold.
I know that on the M54 the section that connects to the inlet manifold end is a rubber hose and they are prone to collapsing under vacuum. This in turn can cause them to crack and leak.

[raymond.harper]

The brake servo is powered by vacuum so I would suspect a leak in the system. Are there any trouble codes?

[Paintermark9]

Hello, there are no fault codes, I'm not sure if it is a face lift model or not, I've only just purchased the car, so this is all new to me, I will try and find out which model it is, will also check the pipes to see what condition they are in,
Thanks for your help

[enuff_zed]

Hello, there are no fault codes, I'm not sure if it is a face lift model or not, I've only just purchased the car, so this is all new to me, I will try and find out which model it is, will also check the pipes to see what condition they are in,
Thanks for your help

What age?
Round rear lights and amber front indicators is pre-facelift.
Stand in front of the engine and look to the passenger side, just behind the air filter box. You should see a red handled dipstick.
If so, it is definitely the M54 engine as the later N52 has no dipstick.

If it is all new to you, give us a rough idea where you are and hopefully there'll be a helpful forum member close enough to give you a little intro to stuff.

[Rockhopper]

its a 2004 car so its the M54 engine.

[enuff_zed]

its a 2004 car so its the M54 engine.

I always check after I gave someone advice based on that, only to later discover it had a private plate.

[Paintermark9]

Hello, just keeping you all updated on the tick over issue, I put the car in to an independent BMW specialist in Coventry, it turns out I had two pressure sensors gone, the mas sensor and a hose, this was all replaced costing nearly a £1000. not cheap, but it has sorted the issue out, and the car runs perfectly, and the mpg has gone up significantly, thanks for your help on this issue.

[Paintermark9]

Hello, just keeping you all updated on the tick over issue, I put the car in to an independent BMW specialist in Coventry, it turns out I had two pressure sensors gone, the mas sensor and a hose, this was all replaced costing nearly a £1000. not cheap, but it has sorted the issue out, and the car runs perfectly, and the mpg has gone up significantly, thanks for your help on this issue.

[j3nks79]

£1000??? What exactly was replaced?

[Paintermark9]

They replaced two pressure sensors, the mass air flow sensor all bmw parts and a hose

[enuff_zed]

They replaced two pressure sensors, the mass air flow sensor all bmw parts and a hose

Wow!
Time to find a handy forum member near you to help you keep future costs down!
But at least it's sorted.

[Paintermark9]

Thank you, that would be handy to have

[enuff_zed]

Thank you, that would be handy to have

Just out of interest, do you have the part numbers of the bits they replaced?
Would like to see what we could find them for, just to give you a rough idea of what a diy price would have been.
If it was the two sensors on the master cylinder, and the vacuum hose to the servo, then along with the MAF, that's a maximum of one hour labour.

[Paintermark9]

Hello, no sorry I don't have any part numbers, but do feel I paid a lot in labour, even though they said they had fitted the maf sensor for free.