1998 E39 540i Stalling

[jamesy]

I have read and searched for possible problems and come up with nothing. My 540i that i have just purchased is stalling when i start it up. It is doing this about 50% of the time. When its going to stall nothing can stop it even if i try to keep the revs high it will still stall. After it stalls it may stall the next few times i try to start it but it will never take more than 5 times before it starts. General driving is fine although it has stalled twice while driving when i have been slowing down at low revs. I have cleaned the MAF using CRC MAF Cleaner. And i have cleaned the seized ICV using TB Cleaner.This has not made the stalling stop although it has made the car run smoother. What do I do next ? Thanks In Advance!

[Renescent]

Fuel filter? You have spark and intermittent fuel (it seems). Any codes?

[jamesy]

Fuel filter? You have spark and intermittent fuel (it seems). Any codes?

Hey i will get my codes pulled on monday nz time. What does what you said mean ? is it a big problem?

[larrym3711]

Without going into a lot of detail at this point, you are on the right track to find your problem. In order of likelihood, you may have a fuel delivery problem due either to a partially clogged fuel filter or a failing fuel pump. Cleaning the MAF rarely fixes a failing MAF, and its not clear your ICV is really working properly. You may also have an input leak. A smoke test will ferret that out if needed. Other considerations include a bad door on the DISA valve, clogged CATS, or bad O2 sensors. Ignition coils or spark plugs being bad is less likely at this point. Getting any stored codes read is your best bet at this point. Also, realize a failing CCV valve can cause poor running as well. Let's start with the codes, if any, for now......

Larrym3711
2001 540iA Sport

[Graham E39 528i]

The first thing to do is measure the fuel pressure and see if it meets spec.

Test 1 is measure idling pressure. Test 2 is see how the pressure decays with the engine stopped.

[jamesy]

The first thing to do is measure the fuel pressure and see if it meets spec.

Test 1 is measure idling pressure. Test 2 is see how the pressure decays with the engine stopped.

Thanks alot but how do i do the above Thankyou

[Graham E39 528i]

You need to procure a fuel pressure tester. They are like tire pressure gauges with a hose and a fitting that will attach to the fuel rail. The fuel rail has a Schrader valve that will allow you to attach the tester to the rail.

Do you have a copy of Bentley (the manual for our cars)? The details of the tests are found within this book. If you don't, I can look up the data for you.

I'm going to bed right now. Let me know tomorrow.

[JimLev]

You should have at least 50 PSI at the schrader valve when the engine is running.
if you just flip the key on and off a few times (engine not running) it should read >40PSI.
The pressure leak down when you shut the engine off is 7 PSI or less in 20 min.

[jamesy]

You need to procure a fuel pressure tester. They are like tire pressure gauges with a hose and a fitting that will attach to the fuel rail. The fuel rail has a Schrader valve that will allow you to attach the tester to the rail.

Do you have a copy of Bentley (the manual for our cars)? The details of the tests are found within this book. If you don't, I can look up the data for you.

I'm going to bed right now. Let me know tomorrow.

I dont have it
"Thanks

[Graham E39 528i]

Jim has provided the details. Its more or less the same as my car.

If the pressures are good, the problem is with the injectors or its not fuel related. If the pressures are bad then you have a problem upstream of the fuel rail.

[edjack]

I don't believe he has the Schrader valve; mine doesn't. It requires a T-fitting to tap into the fuel line under the hood.

[Graham E39 528i]

It looks like Ed is right. No Schrader valve on early 540s (that sucks). You will have to tap into the fuel pressure line.

The steps are:

• Remove engine cover
• Disconnect and remove fuel supply line from left side of fuel rail (slide locking collars and pull apart, if they are stuck spray WD-40 on them)
• You will use a fuel pressure gauge kit that will allow you to T-line the gauge using some short sections of rubber fuel hose and some worm drive clamps (substituting for the quick release fuel hose)
• Perform tests: Test 1 (pressure when idling) & test 2 (pressure after the car has been turned off and you wait 20 minutes)
• Report back

Viel Gluck!

[jamesy]

hey guys . SO i scanned my car and i got cam position sensor code and hot film mass airflow sensor and also continuous power supply? these didnt have p codes with them so i am unsure of what to do?

[KeithM62]

hey guys . SO i scanned my car and i got cam position sensor code and hot film mass airflow sensor and also continuous power supply? these didnt have p codes with them so i am unsure of what to do?

*BUMP*

I'm curious about this, as I've been experiencing the same issue on my 540i. Ran a code reader to find the cam position sensor (P0340) and "ignition system or misfire" (P1396).

[peter540]

To throw in another idea, my '03 540 had a similar issue. Turned out the back of the CCV (on the back of the intake manifold), where the tube connects to it, was completely toast. You might, in other words, check for vacuum leaks.

--Peter