Car bogs down at kickdown.... - United Bimmer Community

**alpine wiess 325is** · 03-19-2008, 01:51 PM

My car recently has been giving me problems. When I press on the accelerator and engage kickdown (its an auto) the car acts like its hit the rev limiter, when i know its not, the rpms are too low....can anyone tell me whats the problem? I already switched out the coils with my e34 and its the same thing, im waiting on a fuel filter, but i have a feeling thats not the problem. The engine has the dreaded bosch platinum +4's which foul up on the m50's. But lets say i change all that, and it still does it, what do you think the problem can be? I think its my VANOS solenoid, or my cam position sensor....so if anyone can help me out that would be great..Thanks

**David Mc** · 03-20-2008, 05:29 PM

Unless you have pleanty of money to throw around, you need to get the fault codes read. Sensors are not cheap and BMWs have plenty of them so changing them by trial and error is time consuming, frustrating, expensive and unnecessary. A handheld Diagnostic code reader or a Carsoft 6.5 interface (if you have a laptop) will both cost around US$150, and you will learn heaps more about your car than having to rely on someone without full knowledge of all the symptoms trying to diagnose the problem.

**alpine wiess 325is** · 03-22-2008, 12:50 AM

Let me be more clear on the problem, basically the engine is cutting out after a certain rpm (iono exactly cuz my gauges dont work, but i want to say 4500) it always happens at that range, if i drive the car less spirited i dont have any problems. It when i get in the upper rev range my engine cuts out, there must be someone that had the similar problem on here, there is no light (indicator lights work) on so i dont think its a sensor. it seems like the DME is protecting the motor or somthing iono its weird it just cuts out. Plus if i had a code reader, it would be pointless to come on the forums and ask for help, cuz i could just figure it out myself, i just want some ideas on how i can approach this problem, or if anyone had a similar problem. From my experience with bm's is that most of them have similar problems....

**alpine wiess 325is** · 03-22-2008, 02:09 AM

I know its late, and probably no one will be online to help me, but if i can get some input on this problem, i still havnt fixed the gauge problem yet so iono if a stomp test will be accurate, or will work so i dont want to try it, there must be someone out there that had a similar problem anyone? btw, i switched coils from known good car and no improvement, so coils plugs are good, what can it be? Is my DME f***ed UP? if it is how is the car running? God i need help with this.....

**David Mc** · 03-22-2008, 05:52 AM

It sounds like a fuel problem - dirty fuel filter or faulty fuel pump would be most likely. The tip is that you say that the problem only appears during 'spirited' driving. Spirited driving = higher rpm = higher fuel demand so if there is a problem with the fuel system, this is when it will be evident. Spark plugs with too great an electrode gap will also cause this problem under similar circumstances as the rise time for the spark is less at high rpm. Forums or no forums a code reader is still a good investment.

**alpine wiess 325is** · 03-23-2008, 01:29 AM

Would the fuel pressure regulator cause that problem too? And does the code reader even detect that?

**David Mc** · 03-23-2008, 02:07 AM

Could be low fuel pressure and whilst a code reader won't check fuel pressure, it will check the electrics related to the fuel pump as well as Mass Airflow Sensor and Oxygen Sensor outputs to ensure that the problem is not due to the mixture bing leaned out by the computer. It will also check whether your Crank Angle sensor is working properly and ensure that its signal is not breaking down at high rpm.

I have worked on cars for over 30 years and have quals in Mechanical Engineering but I would not be without a code reader when working on my E36 due to the number and complexity of electronic inputs to the engine management system.

**alpine wiess 325is** · 03-23-2008, 03:12 AM

Well im not disputing the effectiveness of a code reader im sure its a fine instrument, i just cant afford one right now, so all i can do is ask you folks on the forum for ideas....but my suspicions were the fuel delivery system as well, im getting a fuel filter this week so we will see what happens.....

**mullethunter3** · 03-24-2008, 03:58 PM

Why not do the stomp test? It's free and easy and would help us out in diagnosing your problem...

**alpine wiess 325is** · 03-25-2008, 10:03 PM

A very strange thing happened today. My cars problem fixed it self, it doesn't seem to starve for fuel anymore. I also received the gauge cluster on Ebay, and all my gauges work now, the thing is, after i changed the cluster i drove the car to see at what rpm the car was bogging down, and it didn't do it at all, do you think, the cluster had something to do with it? I know it sounds ridiculous, but maybe the DME and cluster talk to each other somehow iono... I also did change my oil to mobil 1 10w40 highmileage as well.

witeshark · 03-25-2008, 11:33 PM

Well that's interesting. Please keep us posted!