Need help with my z4

[whoath]

This is my first time on here would just like to say hello. My name is Wayne I live in sunny Florida. I owned 2 2005 BMW Z4`s both 2.5i. I love my Z4 and would love to fix it. I did a hydrographic overhaul on the inside of my car. I want to do a lot more to it but need to fix this first.
About 2 months ago my car started giving me problems, when I step on the brake the engine would rev up about 500 rpms . When I am at a stop I sometimes have to put it in park to keep the idle down. When I let the brake off it almost wants to die little hesitation and then the subsides and then I can drive as normal. I t does best in the morning or if the ac is on. I drive 100 miles a day I really need to fix this. It is showing some codes but as we all know some codes could mean a lot of things. The strangest thing it does is when you put the car in drive push the brake and the gas to spin the tire it does nothing and I mean nothing like the gas pedal is not working at all. I do not beat my car it was just the best way to tell you what it is doing. I rebuilt the vanos over the weekend doing better to power only not the problem at hand, any help or suggestions would be great.
The MAF has been cleaned only....
It was showing codes po174, po171, po102,po1447. I cleared them all earlier now it is only showing po102 but the problem is still there.
THANKS

Wayne

 

[Chris_D]

First off, welcome to the forum.
Secondly, make an introduction to yourself and your zed before the forum storm-troopers arrive.
Thirdly, you will find we're all willing to impart wisdom, guidance and good advice but this can only be based on you having given a full, clear and concise description of the problem.
That being said, it would be useful to know the particular codes that you managed to derive rather than just dismissing them out of hand as well as a bit more detail.
It would also be useful for you to focus a little on your grammar and sentence construction as it's not perfect and doesn't lend itself to being a clear description of the issues you're experiencing.

 

[Marlon]

Would that be a C - then Chris?

OP - the codes may indeed mean anything, including showing what the actual problem is.
Welcome to the Forum.

 

[Chris_D]

Would that be a C - then Chris?

OP - the codes may indeed mean anything, including showing what the actual problem is.
Welcome to the Forum.

That would be a C- and a note to his English tutor advising to give extra homework to do at the weekend! :wink:

 

[raymond.harper]

P0102 - Mass Air Flow Sensor Circuit Low

Mass Air Flow Sensor (MAF)

Mass Air Flow Sensor (MAF)

The mass air flow or MAF sensor measures the amount of air entering the engine. The engine computer (ECM) uses the mass air flow signal to calculate the amount of fuel injected (read more how the MAF sensor works below). The code P0102 is set when the signal from the mass air flow sensor is lower than expected. Often a car may exhibit some driveability symptoms, such as lack of power, surging, hesitation on acceleration, hard starting, pinging (detonation), or rough idle when started cold. Often the codes P0171 or P0174 could also be stored along with the code P0102, as the incorrect air flow signal can cause the engine to run lean. The codes P0171 and P0174 indicate a lean condition. Checking the freeze frame might help in the diagnostic process. The freeze frame is stored in the ECM along with the trouble code. The freeze frame contains some recorded parameters (e.g. vehicle speed, engine temperature, fuel trim) at the moment when the fault was detected. The freeze frame can also be accessed with a scan tool.



What could cause the code P0102
- faulty or contaminated mass airflow sensor
- debris blocking the air flow at the mass air flow sensor
- unmetered air leaking past the MAF sensor (vacuum leaks)
- PCV system vacuum leaks
- restricted or collapsed intake air duct
- dirty or restricted air filter
- restricted air screen before the air filter
- improper application of aftermarket components (e.g. cold intake, modified air filter, etc.)
- wrong air flow sensor installed
- electrical problem with the MAF sensor wiring, connector, power supply or ground.
- problem with ECM
- in some cases other issues with the fuel injection system like a clogged catalytic converter or a faulty manifold absolute pressure sensor (MAP) can also cause the code P0102.

 

[Ewazix]

Welcome Wayne, sorry about the up-tight reception :wink:

Some good advice above but starting with something easy which commonly causes similar symptoms might be worth a try. Have a look at your air intake boot/hoses for small splits, any leaks around here play havoc with the whole air/fuelling system. Good luck and do let us know how it gets sorted.

Intake boot split http://www.z4-forum.com/forum/viewtopic.php?t=70223

 

[Stevepj]

From the fault codes you've listed and their causes and effects I'd be suspecting either the brake servo and/or the vacuum pipes between the servo and the inlet manifold.

P0102 - Mass Air Flow Sensor Circuit Low - the engine is receiving unmetered air somewhere after the MAF which will cause the engine to run lean and generate the P0171 and P0174 codes.
Have someone press and release the brake pedal while you listen for hissing at the servo which would indicate a split diaphragm in the servo, you might also hear a leak along the length of the servo vac pipe.
Also press the brake pedal two or three time without the engine running and it should remain firm, if the pedal creeps there's a fault. Keep foot on the pedal and start the engine, the pedal should drop about half an inch as the vacuum builds, if it doesn't drop this indicates a fault as vacuum is not being created to move the diaphragm in the servo.
Check along the length of the vac pipe for leaks and also at the joints particularly where all the various vac pipes come together at the inlet manifold, but as the problem is linked to the application of the brakes I would concentrate my efforts around the servo and it's vac pipe.

 

[whoath]

I thank you all for your help on my problem. I have a few places to check now. I do good work just sometimes it`s hard to diagnose a problem. And having someone else touch it bothers me. My big question of the day is way did pushing to brake make the gas pedal not work. I`ve messed with a lot of cars and never have I seen this problem. I`ve had cars with bad maf sensors, bad coils and just about anything else that could go wrong some I never figured out what it was. I could still push the gas with the brake pushed. (As long as it would start) I will work on the suggestions thanks.

 

[fixit man]

I thank you all for your help on my problem. I have a few places to check now. I do good work just sometimes it`s hard to diagnose a problem. And having someone else touch it bothers me. My big question of the day is way did pushing to brake make the gas pedal not work. I`ve messed with a lot of cars and never have I seen this problem. I`ve had cars with bad maf sensors, bad coils and just about anything else that could go wrong some I never figured out what it was. I could still push the gas with the brake pushed. (As long as it would start) I will work on the suggestions thanks.

check brake servo (Booster), check valve and pipes for leaks , this can cause the issues you are having..good luck

 

[whoath]

Very good, I did a freeze frame on my car today to see what the MAF reading was. Does anyone know what a good one would be at. Right now I am going with the brake servo just because of what happens to my gas pedal when the brake is pushed. But I will leave no stone unturned..... Thanks

 

[goldbcfc]

sounds like the common vacuum leak P0171 P0174 etc.

 

[Lynnbg123]

Have you found and solved this problem, mine is doing the same thing.

 

[firebobby]

Blast from the past