e34 525i M50 Non Vanos - NOT starting after standing long

[JayDrft]

Hi All,

Looking for a bit of guidance here.

As the title states - I have read all the non starting related topics in this section...

A bud of mine and I tackled this issue, first checking the following:

1) No fuel getting to the rail
2) pulled the pump and fuel sender unit out - discovered a bit of a hack job and a missing sender unit(explains why the fuel gauge wasn't working).
3) Fault finded, and noticed that power was jumping terminals due to the hack job where wires were crossed.
4)Sourced a untouched/virgin sender unit assembly, connected the pump up and tested it...when ignition is switched on, pump doesnt churn, when cranking the pump starts up...
5) dropped the pump and sender unit into the tank, cranked it and within 2-3 "swings" it started up.

It idles for about 2-3mins...and then cut out and didnt want to start again.

What could it be? Ive read that its either the crank position sensor or fuel relay...any sure fire ways to diagnose, as this car was running fine, until I parked it for about 3months.:hammerhead:

Any help/guidance would be appreciated.

 

[JohnLod]

Hi All,

Looking for a bit of guidance here.

As the title states - I have read all the non starting related topics in this section...

A bud of mine and I tackled this issue, first checking the following:

1) No fuel getting to the rail
2) pulled the pump and fuel sender unit out - discovered a bit of a hack job and a missing sender unit(explains why the fuel gauge wasn't working).
3) Fault finded, and noticed that power was jumping terminals due to the hack job where wires were crossed.
4)Sourced a untouched/virgin sender unit assembly, connected the pump up and tested it...when ignition is switched on, pump doesnt churn, when cranking the pump starts up...
5) dropped the pump and sender unit into the tank, cranked it and within 2-3 "swings" it started up.

It idles for about 2-3mins...and then cut out and didnt want to start again.

What could it be? Ive read that its either the crank position sensor or fuel relay...any sure fire ways to diagnose, as this car was running fine, until I parked it for about 3months.:hammerhead:

Any help/guidance would be appreciated.

Hi,

Where is the vehicle based?
Just a couple of questions?
Is there power on the fuel pump when you crank the motor?There should be battery voltage.
Is there power on the coils?, you should get battery voltage on the one terminal (think it is terminal 15). Is there spark?
Is there power on the injectors? you should have battery voltage (more or less) on the injectors. The one side will have battery voltage and when you crank the motor the other side should pulse, i use to leave it plugged into the injector and used a test lamp as a electronic multi meter is to slow (unless you have a oscilloscope handy).

Just check on the r/f shock there is a small black box with a fuse able link in it which sometimes blows or cracks, not all have it. you are welcome to call me on 0835466411. The one way to check the pick up is to remove it and then hold it in your hand and then take a screw driver and move it over it quickly and see if the fuel pump starts to activste.

Regards

 

[JohnLod]

Hi All,

Looking for a bit of guidance here.

As the title states - I have read all the non starting related topics in this section...

A bud of mine and I tackled this issue, first checking the following:

1) No fuel getting to the rail
2) pulled the pump and fuel sender unit out - discovered a bit of a hack job and a missing sender unit(explains why the fuel gauge wasn't working).
3) Fault finded, and noticed that power was jumping terminals due to the hack job where wires were crossed.
4)Sourced a untouched/virgin sender unit assembly, connected the pump up and tested it...when ignition is switched on, pump doesnt churn, when cranking the pump starts up...
5) dropped the pump and sender unit into the tank, cranked it and within 2-3 "swings" it started up.

It idles for about 2-3mins...and then cut out and didnt want to start again.

What could it be? Ive read that its either the crank position sensor or fuel relay...any sure fire ways to diagnose, as this car was running fine, until I parked it for about 3months.:hammerhead:

Any help/guidance would be appreciated.

Hi,

Where is the vehicle based?
Just a couple of questions?
Is there power on the fuel pump when you crank the motor?There should be battery voltage.
Is there power on the coils?, you should get battery voltage on the one terminal (think it is terminal 15). Is there spark?
Is there power on the injectors? you should have battery voltage (more or less) on the injectors. The one side will have battery voltage and when you crank the motor the other side should pulse, i use to leave it plugged into the injector and used a test lamp as a electronic multi meter is to slow (unless you have a oscilloscope handy).

Just check on the r/f shock there is a small black box with a fuse able link in it which sometimes blows or cracks, not all have it. you are welcome to call me on 0835466411. The one way to check the pick up is to remove it and then hold it in your hand and then take a screw driver and move it over it quickly and see if the fuel pump starts to activate.

Regards

 

[JayDrft]

Hi John...

Thanks for your guidance - I will need to check all the points you mentioned, I will update once I have checked the said.

Thanks again

 

[JayDrft]

Just some feedback regarding this problem - it may help someone in the future as not a lot of help was sought from the forum members regarding this problem.

Fault finded, checked the pump and by process of elimination, swopped multiple relays out, tested all connections with a multimeter, checked fuel filter/pump etc...finally when it got to checking continuity - we found the problem.

Between the fuel relay(drivers side) and Fuel pump fuse(passenger side), there was continuity - indicating a proper connection.

From the fuel pump fuse to the fuel pump - DEAD....! although we were getting intermittent power(0.02 - 6volts) at the fuel pump when cranking the motor it was just not enough to get going - so for peace of mind we done a temporary connection between the fuel box and fuel pump power wire, cranked the motor for a few seconds...nothing happened but after cranking a bit more - it burst into life again, as it was intended to the last time we tackled this exercise.

Conclusion - faulty/broken power supply wire within the fuel system harness.

Had so much confidence, drove it on the highway for at least 2 turn offs, checked fluids and tyre pressures...all sound and well.

Thanks for your input John...much appreciated.

 

[Nikhil]

:bravo: