Welcome to Bimmerfest -- The #1 Online Community for BMW related information! Please enjoy the discussion forums below and share your experiences with the 200,000 current, new and past BMW owners. The forums are broken out by car model and into other special interest sections such as BMW European Delivery and a special forum to voice your questions to the many BMW dealers on the site to assist our members!

Please follow the links below to help get you started!

Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > Z Series > E85 / E86 Z4 (2003-2008)

E85 / E86 Z4 (2003-2008)
E85 Z4 convertible and E86 Z4 coupe talk with our BMW gurus here.

Reply
 
Thread Tools Display Modes
  #1  
Old 11-22-2012, 07:20 AM
ZEEBOY ZEEBOY is offline
Officially Welcomed to the 'Fest
Location: SW Ohio
 
Join Date: Nov 2006
Posts: 132
Mein Auto: 2001 Z3 Coupe and 2003 Z4
Z4 getting more difficult to start

Not a crisis at this point...but I notice that our 2003 Z4 (2.5 steptronic, 65k miles) now somtimes requires more than 1 turn of the key to start the engine (the starter spins but the engine does not fire)...sometimes requiring 2/3 separate key turns to start the engine. Once running, the car runs flawlessly. It did not used to do this....in the past it always started with one turn of the key. Was wondering if anyone has gone through this?

Last edited by ZEEBOY; 11-22-2012 at 07:22 AM.
Reply With Quote
Ads by Google
  #2  
Old 11-22-2012, 08:10 AM
wifesauto wifesauto is offline
Officially Welcomed to the 'Fest
Location: nj
 
Join Date: Jan 2012
Posts: 267
Mein Auto: sloporsche
long list of things that it could be.........battery,starter,fuel pump/check valve,spark plugs,ignition switch ,fuel filter and relays. a pro repair manual and pro test equiptment will speed the process of testing.
Reply With Quote
  #3  
Old 11-22-2012, 09:53 AM
ZEEBOY ZEEBOY is offline
Officially Welcomed to the 'Fest
Location: SW Ohio
 
Join Date: Nov 2006
Posts: 132
Mein Auto: 2001 Z3 Coupe and 2003 Z4
As I mentioned the starter spins with authority, so I THINK the battery and starter could be eliminated.....what check valve and relay are you referring to? THANKS!
Reply With Quote
  #4  
Old 11-22-2012, 04:51 PM
shipkiller's Avatar
shipkiller shipkiller is offline
Underway on Nuclear Power
Location: Virginia Beach, VA
 
Join Date: Nov 2007
Posts: 779
Mein Auto: Me
When was the last time you changed your spark plugs and air filter? Also, how often do you put a can of GOOD fuel treatment in the car?
__________________
.
.
How does something immoral, when done privately, become moral when it is done collectively?
Furthermore, does legality establish morality?
Slavery was legal; apartheid was legal; Stalinist, Nazi, and Maoist purges were legal. Clearly, the fact of legality does not justify these crimes. Legality, alone, cannot be the talisman of morel people. - Walter E. Williams
Reply With Quote
  #5  
Old 11-22-2012, 05:57 PM
wifesauto wifesauto is offline
Officially Welcomed to the 'Fest
Location: nj
 
Join Date: Jan 2012
Posts: 267
Mein Auto: sloporsche
ignition system may have a relay,electric fuel pump has a relay. there is a check valve in the fuel line that keeps a little psi on the system. find out if its no fuel or no spark that is causing the no start .imho
Reply With Quote
  #6  
Old 11-23-2012, 06:44 AM
ZEEBOY ZEEBOY is offline
Officially Welcomed to the 'Fest
Location: SW Ohio
 
Join Date: Nov 2006
Posts: 132
Mein Auto: 2001 Z3 Coupe and 2003 Z4
Shipkiller, I have never changed the spark plugs, so that is definitely a good place to start.....air filter has been changed twice in 3 years and I have given two techron treatments over that same period...also I use the only (I think) TOP TIER gas available in sw Ohio, Shell premium religously...as I reflect on this problem, it seems to only ocurr when the car has not been started over a protracted period of time...almost as if the fuel has "bled down" and needs to be pumped back into the system....I think the next time the car has been sitting for a while I will simply leave the ignition key on for a few seconds longer before turning to start to see if that helps...of course this does not fix anything but may be a pointer toward root cause.... just my thoughts...
Reply With Quote
  #7  
Old 11-23-2012, 08:20 AM
mnguyen84 mnguyen84 is offline
Registered User
Location: CA, USA
 
Join Date: Nov 2012
Posts: 12
Mein Auto: 96 z3 5spd
i would test the battery first. you can either take it to autozone. if the battery is bad then it's ur battery or alternator. if all is good, then you probably need a new starter. i think autozone can test starters too.
Reply With Quote
  #8  
Old 11-23-2012, 08:41 AM
ZEEBOY ZEEBOY is offline
Officially Welcomed to the 'Fest
Location: SW Ohio
 
Join Date: Nov 2006
Posts: 132
Mein Auto: 2001 Z3 Coupe and 2003 Z4
mnguyen84, battery and starter are robust...the starter always spins with plenty of torque...
Reply With Quote
  #9  
Old 11-23-2012, 08:41 AM
wifesauto wifesauto is offline
Officially Welcomed to the 'Fest
Location: nj
 
Join Date: Jan 2012
Posts: 267
Mein Auto: sloporsche
the owner says he believes it is cranking over okay
Reply With Quote
  #10  
Old 11-23-2012, 08:49 AM
z4mconona z4mconona is offline
Registered User
Location: Orlando, FL
 
Join Date: Jul 2012
Posts: 22
Mein Auto: '04Z4 3.0, '07X3 3siMS
Had a similar issue last March... spin starter but no ignition fire cold start, (warm start thereafter no problem - after tender placed on battery for a charge, also sometimes a yellow brake light warning). Result.. battery was weak (4 yrs OE) OEM replaced and registered**. Has been okay since then. Battery first thing to eliminate... just saying.

** registration not needed E85 - just had low voltage diag report done and all faults cleared at indy shop i.e. shipkiller is right on the beam

Last edited by z4mconona; 11-23-2012 at 11:28 AM. Reason: clarity - facts
Reply With Quote
  #11  
Old 11-23-2012, 09:12 AM
shipkiller's Avatar
shipkiller shipkiller is offline
Underway on Nuclear Power
Location: Virginia Beach, VA
 
Join Date: Nov 2007
Posts: 779
Mein Auto: Me
Quote:
Originally Posted by ZEEBOY View Post
Shipkiller, I have never changed the spark plugs, so that is definitely a good place to start.....air filter has been changed twice in 3 years and I have given two techron treatments over that same period...also I use the only (I think) TOP TIER gas available in sw Ohio, Shell premium religously...as I reflect on this problem, it seems to only ocurr when the car has not been started over a protracted period of time...almost as if the fuel has "bled down" and needs to be pumped back into the system....I think the next time the car has been sitting for a while I will simply leave the ignition key on for a few seconds longer before turning to start to see if that helps...of course this does not fix anything but may be a pointer toward root cause.... just my thoughts...

When problems like this crop up, ALWAYS, ALWAYS do the little, easy things before you start assuming starter, fuel pump injectors etc...

Your first post ruled all of those out....


I left battery out of that list because it CAN in some circumstances cause this.

It does sound like a issue with the fuel pressure slowly bleeding off over a long period of time, but if your plugs are worn, they may not fire properly to get the very lean mixture in the cylinders to fire, hence the second or third try, then it runs as it should. Even my 2008 MC and 2003 Roadster will do this after sitting for a week or so, or when it gets cold out.

There is no mechanical fuel pressure regulator like on an American car. Fuel pressure is controlled by the EKPS module which regulates how the fuel pump runs.

BMW's description:
Electronically controlled fuel pump

The electronically controlled fuel pump system controls the electric fuel pump (EKP) as required. The fuel rate required by the engine at any time is converted by the electronically controlled fuel pump system into the required capacity of the EKP.
Brief description of components

Control module
The EKP control module is located in the luggage compartment on the right-hand side beside the wheel arch. The EKP control module controls the speed of the EKP by means of pulse width modulation of the EKP output voltage according to the fuel request. The supply characteristic curve of the EKP for the corresponding model series is stored in the coding data. The EKP control module ensures reliable activation of the EKP up to a system voltage including 6 V.
The Digital Engine Electronics (DME) control module transmits the request for the currently required fuel rate to the EKP control module.
Diagnosis CAN
The communication of the EKP control module with the DME control module takes place across the diagnosis CAN. The required fuel rate is passed on to the EKP control module by the DME control module in a message across diagnosis CAN.
Electric fuel pump (EKP)
The EKP is located in the fuel tank.
Function

The EKP control module controls the EKP according to the system mode of the fuel supply system in the operation of the vehicle. The fuel output rate of the EKP is activated and regulated according to a given characteristic curve via engine speed recognition. The reference variables for this are the fuel requirement of the engine and the fuel circuit systems.
The DME control module determines the fuel requirement of the engine and adds an additional quantity for operation of the suction jet pump (SSP). The total required amount of fuel is transmitted as a message across the diagnosis CAN to the EKP control module.
The EKP control module converts the received diagnosis CAN message into a pulse-width modulated output voltage for the EKP and thus controls the speed of the EKP.
The EKP control module is activated via terminal 15. This is followed by the initialization in which the EKP to activated 100 %. On completion of the initialization, the EKP control module regulates the EKP according to the supply rate set by the DME.
Emergency operation

If there is no communication with the DME or this is defective, the EKP control module switches to emergency operation. The electric fuel pump is fully activated.
Important

Always ensure that the EKP control module is mounted according to regulations! Correct mounting ensures reliable heat dissipation. If this is not the case, it leads to overheating of the EKP control module and its failure. The result will be a breakdown.
During repair work on the fuel system, the EKP system has to be de-energized (risk of fire). To do so, either unplug the fuse in the rear distribution box or disconnect the plug connector to the electronic fuel pump at the fuel tank.



Here are some PDF's to help you out.


All that being said, if the battery is good (no registration required on the Z4, I don't care what the dealer says....most are idiots...) and you can live with the issue, leave it alone. To replace the fuel pump/filter, you must drop the compete exhaust system (from the header back) and the rear structure reinforcement plate to get to the fuel pump which is inside the fuel tank.
__________________
.
.
How does something immoral, when done privately, become moral when it is done collectively?
Furthermore, does legality establish morality?
Slavery was legal; apartheid was legal; Stalinist, Nazi, and Maoist purges were legal. Clearly, the fact of legality does not justify these crimes. Legality, alone, cannot be the talisman of morel people. - Walter E. Williams
Reply With Quote
  #12  
Old 11-23-2012, 09:30 AM
z4mconona z4mconona is offline
Registered User
Location: Orlando, FL
 
Join Date: Jul 2012
Posts: 22
Mein Auto: '04Z4 3.0, '07X3 3siMS
Go NAVY!
Reply With Quote
Reply

Bookmarks


Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > Z Series > E85 / E86 Z4 (2003-2008)
Today's Posts Search
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On



Forum Jump


All times are GMT -7. The time now is 12:55 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
© 2001-2011 performanceIX, Inc. All Rights Reserved .: guidelines .:. privacy .:. terms