2001 bmw 525i intermittend missfire

[LTX_REAPER]

Hi Guys.

I have today ran iinto yet another problem with my car, intermittend missfires or cylinder completely dead every now and then, i have replaced the spark plugs and swopped the coils around, problem persists, first it was on cylinder 1, now its on cylinder 5, when comming toward a halt the car shakes badly and it can barely pick up speed, now check engine light or anything wrong on the dash.

Any ideas ?

 

[DoctorJ]

Check and replace your CCV (PCV ) and 4 (think it's 4) rubber hoses associated with it.

Sounds like a vacuum leak.

 

[LTX_REAPER]

Check and replace your CCV (PCV ) and 4 (think it's 4) rubber hoses associated with it.

Sounds like a vacuum leak.

Thanks doctorj, will have a look

 

[S1NGH 911]

How much of fuel did you have in the tank when this happened?

 

[LTX_REAPER]

How much of fuel did you have in the tank when this happened?

Hi Singh, just above a quarter tank, have today replace 3 coils and still the same issue, have orderd a obd scanner, but not sure if its going to help since its not even giving me a check engine light, i have also done the ccv tests that they show on youtube, no problem found there.

This car is giving me grey hairs

 

[S1NGH 911]

Have you checked the MAF?


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[LTX_REAPER]

Have you checked the MAF?


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I Have cleaned the maf and even unplugged it, runs worse when unplugged

 

[AdiS]

Error codes don't always trigger a CEL, so def get the codes read.

I suspect vacuum leak.

 

[S1NGH 911]

The drop in the E39 fuel tank is known to move out of place. I had this issue years back, when the fuel guage was near 15L the car would misfire, turned out to be the drop in the fuel tank.


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[LTX_REAPER]

The drop in the E39 fuel tank is known to move out of place. I had this issue years back, when the fuel guage was near 15L the car would misfire, turned out to be the drop in the fuel tank.


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Thank you, I will fill it up today and see what it does

 

[Rayzor]

You can also check the vanos solenoids, in fact just remove them and clean them out for good measure.

 

[LTX_REAPER]

I have now filled the car and used a bottle of injector cleaner yesterday, no difference, seems i would have to wait for my scanner.

Thanks Razor, will try that

 

[DoctorJ]

My 2001 e46 330i had a missfire when starting up, and after a while it would go away, but come back at random. When very cold it was significantly worse. Sometimes it would even switch off a cylinder, making driving it near impossible. Switch the car off and start again, and it would be happy.

Diagnostics would register the missfire on a cylinder, you clear the code, and the missfire would register on a different cylinder, at random.

Ended up replacing the ccv and hoses, was about 5k, and she was happy as ever.

I am still pretty sure that is where your problem lies. Common on these engines, and at that age, highly likely you have a perished hose.

You can even start by replacing the hoses one by one.

Quite a few other members here experienced similar issues on their cars over the years. Fordkoppie and Blueshirt comes to mind.

 

[LTX_REAPER]

Hi Guys, Ran a scan on the car and this is what i found on ecm:error code f0 240 misfire cylinder 3, misfire with cylinder cutout [misfire carb_a]

 

[LTX_REAPER]

ok, Going to follow everyone's advice and strip of intake to look for vacuum leaks, will update with what i find, thanks so far for everyone's advice

 

[SlimmJimm]

Any update? Mums 120i doing same thing, waiting for my scan tool lol

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[zaleonardz]

Check for bad grounds as well. Check the DME control box for water