BMW cuts out 5 minutes after starting

[Malcolmkeith]

Can any one help with my 1996 525i.
A couple of days ago I started my BMW and backed it out of my garage. It always starts without a problem and I let it run to warm up..After 5 minutes the engine cut out and would not restart. I tried to start it after an hour then after 2 hours but no joy. Cranking is fine. After 8 hours it started again and did exactly the same thing (i.e cut out after 5 minutes.) Yesterday was a repeat - started first time, ran smoothly and stopped after 5 minutes.
Any suggestions would be appreciated

[d_a_n1979]

Malcolmkeith said:

Can any one help with my 1996 525i.
A couple of days ago I started my BMW and backed it out of my garage. It always starts without a problem and I let it run to warm up..After 5 minutes the engine cut out and would not restart. I tried to start it after an hour then after 2 hours but no joy. Cranking is fine. After 8 hours it started again and did exactly the same thing (i.e cut out after 5 minutes.) Yesterday was a repeat - started first time, ran smoothly and stopped after 5 minutes.
Any suggestions would be appreciated

You need to find someone with INPA local to you (indy BMW garage, someone on these pages or Facebook if you're on there etc) to read the codes properly and see the live data & that'll let you know what codes have been stored etc... Don't use a generic reader, it'll just give you generic codes

But the usual suspects are:

- Air intake boot split between the MAF and throttle body; check all this carefully and if any splits/cracks, replace those sections
- Cam/crank sensor failed or failing (more than likely this); they need to be replaced with OEM BMW sensors ONLY, as aftermarket ones are crap at best
- MAF failing or failed; again, needs to be replaced with OEM BMW only
- You need to listen for the fuel pump priming when you turn the ignition on, but not start the engine. So confirm this if you can

You can unplug the MAF and run it that way and see how it behaves first

[sortedcossie]

Cam/crank sensor failing to pick up signal once it's starts to get warm.

[Scrump]

sortedcossie said:

Cam/crank sensor failing to pick up signal once it's starts to get warm.

I had this on my old e39 and it caused the same symptoms as you are experiencing.

[NMNeil]

Malcolmkeith said:

Can any one help with my 1996 525i.
A couple of days ago I started my BMW and backed it out of my garage. It always starts without a problem and I let it run to warm up..After 5 minutes the engine cut out and would not restart. I tried to start it after an hour then after 2 hours but no joy. Cranking is fine. After 8 hours it started again and did exactly the same thing (i.e cut out after 5 minutes.) Yesterday was a repeat - started first time, ran smoothly and stopped after 5 minutes.
Any suggestions would be appreciated

When did you last change the fuel filter?

[g3org3y]

d_a_n1979 said:

- Cam/crank sensor failed or failing (more than likely this); they need to be replaced with OEM BMW sensors ONLY, as aftermarket ones are crap at best

That would be my feeling too.

Re the cutting out, is that instant or does it run poorly for a period of time before that?

Apart from the cutting out, does the car run fine, no hesitation etc?

[Malcolmkeith]

Big thank you to those who responded.
Re your question about how it runs before stalling.-It runs fine for the whole 5 minutes.
Cam/crank sensor sounds likely culprit. I will try to find someone with an INPA.

[Elliot2000]

d_a_n1979 said:

You need to find someone with INPA local to you (indy BMW garage, someone on these pages or Facebook if you're on there etc) to read the codes properly and see the live data & that'll let you know what codes have been stored etc... Don't use a generic reader, it'll just give you generic codes

But the usual suspects are:

- Air intake boot split between the MAF and throttle body; check all this carefully and if any splits/cracks, replace those sections
- Cam/crank sensor failed or failing (more than likely this); they need to be replaced with OEM BMW sensors ONLY, as aftermarket ones are crap at best
- MAF failing or failed; again, needs to be replaced with OEM BMW only
- You need to listen for the fuel pump priming when you turn the ignition on, but not start the engine. So confirm this if you can

You can unplug the MAF and run it that way and see how it behaves first

You can’t disconnect the maf on these early ones - it will just cut out as it doesn’t run on an default value like the later ones.

Worth also checking the front crank pulley as this is where the crank sensor pickup is and they can begin to droop and go lopsided on old ones which interfere with the pickup signal and cause non starting and cutting out.

[d_a_n1979]

Elliot2000 said:

d_a_n1979 said:

You need to find someone with INPA local to you (indy BMW garage, someone on these pages or Facebook if you're on there etc) to read the codes properly and see the live data & that'll let you know what codes have been stored etc... Don't use a generic reader, it'll just give you generic codes

But the usual suspects are:

- Air intake boot split between the MAF and throttle body; check all this carefully and if any splits/cracks, replace those sections
- Cam/crank sensor failed or failing (more than likely this); they need to be replaced with OEM BMW sensors ONLY, as aftermarket ones are crap at best
- MAF failing or failed; again, needs to be replaced with OEM BMW only
- You need to listen for the fuel pump priming when you turn the ignition on, but not start the engine. So confirm this if you can

You can unplug the MAF and run it that way and see how it behaves first

You can’t disconnect the maf on these early ones - it will just cut out as it doesn’t run on an default value like the later ones.

Worth also checking the front crank pulley as this is where the crank sensor pickup is and they can begin to droop and go lopsided on old ones which interfere with the pickup signal and cause non starting and cutting out.

Ah hadn't realised; thanks for pointing that out

[E-bmw]

Elliot2000 said:

d_a_n1979 said:

You need to find someone with INPA local to you (indy BMW garage, someone on these pages or Facebook if you're on there etc) to read the codes properly and see the live data & that'll let you know what codes have been stored etc... Don't use a generic reader, it'll just give you generic codes

But the usual suspects are:

- Air intake boot split between the MAF and throttle body; check all this carefully and if any splits/cracks, replace those sections
- Cam/crank sensor failed or failing (more than likely this); they need to be replaced with OEM BMW sensors ONLY, as aftermarket ones are crap at best
- MAF failing or failed; again, needs to be replaced with OEM BMW only
- You need to listen for the fuel pump priming when you turn the ignition on, but not start the engine. So confirm this if you can

You can unplug the MAF and run it that way and see how it behaves first

You can’t disconnect the maf on these early ones - it will just cut out as it doesn’t run on an default value like the later ones.

Is there a cut off date for the change as my 98 328 would start & run pretty well with the MAF disconnected when I had an issue with it, but would cut out when I had the intermittent issue on the plug/socket.

[Malcolmkeith]

Just to let people know;- the fault was diagnosed as the crank sensor by H W Autos. Sensor was replaced and all is now well. Thanks to all contributors and to HW Autos (Four Marks) who were excellent.

[d_a_n1979]

Malcolmkeith said:

Just to let people know;- the fault was diagnosed as the crank sensor by H W Autos. Sensor was replaced and all is now well. Thanks to all contributors and to HW Autos (Four Marks) who were excellent.

As per my first guesses then Glad it's all sorted

I hope they fitted an OEM BMW sensor and not an aftermarket one

[geeks]

d_a_n1979 said:

Malcolmkeith said:

Just to let people know;- the fault was diagnosed as the crank sensor by H W Autos. Sensor was replaced and all is now well. Thanks to all contributors and to HW Autos (Four Marks) who were excellent.

As per my first guesses then Glad it's all sorted

I hope they fitted an OEM BMW sensor and not an aftermarket one

That was going to be my guess too, not too dissimilar behaviour on my 330 and it was the inlet camshaft sensor. As d_a_n says make sure they use an OEM sensor from BMW or you'll likely be having it replaced again inside a couple of years.

[Olivergt]

Glad to hear it's all sorted.

It's always good to get an update on issues with the solution, can add to the memory bank of fault x might be solution y.

[Touring442]

Elliot2000 said:

You can’t disconnect the maf on these early ones - it will just cut out as it doesn’t run on an default value like the later ones.

You can, it's M3.3.1 Motronic; I had a 1995 525i M50TU with a running problem and once the MAF was disconnected it went a lot better. It turned out to be a Chinese no name no blame MAF that was NFG. I had the same thing on a 1992 E36 320i (M3.1 non vanos) and others the most recent being a 1996 528i E39.

The other E34 problem with cutting out is the fuel pump. They start to seize, overload and stop working. They normally restart immediately but for a couple of seconds only. Eventually they just stop working completely.

When it stops, pull the intake boot off and fire a bit of fuel in past the throttle body straight away. If it bursts into life, my $$$ is on the pump. If it doesn't, it's likely to be the crank sensor.

Only buy a genuine Bosch one btw or from BMW.

[geeks]

Touring442 said:

Only buy a genuine Bosch one btw or from BMW.

the part of Bosch that makes sensors has been sold and already people are seeing issues with Bosch sensors, so even they aren't as reliable as they used to be!

[Touring442]

Bloody hell. :-(

I bought my last one from BMW. It was ££££ and I had to blow the dust off of it.