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Djimyh

530d loss of power on incline

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Hi guys need some serious help

 

Just did a a service and changed the fuel filter (want giving issues but thought why not). Now the car randomly lost power on an uphill incline, and after a few mins of driving power came back. This happened a few times - thought it was the fuel filter so swapped out back to the old one and drive fine for a while day then presented with the same problem. On a side note this problem never occurred before.

 

Got Error code as pictured 4704 on the new filter as well as the old one after I put it back in. The power now sporadically comes back and goes, sometimes on start won't rev past 3000rpm. The car starts up fine all the time though no problem on that end...

 

Any ideas guys?? 

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The supply pressure seems very low on those codes. Something wrong with supply pressure sensor or its wiring on top of fuel filter? Check the supply pressure on status page how it behaves when ignition pos. 1/2.

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I'm out at the moment guys, I'll sort it tomorrow and send some pics of that's ok - thank you very much

P.s the sensor at the top of the fuel filter seems fine but I'll get some pics taken

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22 hours ago, Clavurion said:

The supply pressure seems very low on those codes. Something wrong with supply pressure sensor or its wiring on top of fuel filter? Check the supply pressure on status page how it behaves when ignition pos. 1/2.

Hi I've taken some pictures of the sensor and supply pressure on ignition 1/2 please see attached

22 hours ago, stew99 said:

What's the connection to the sensor on the top of filter like? Would it be loose. As that sensor reads the pre engine fuel pressure. 

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1 minute ago, stew99 said:

Sounds like a fuel pump has failed. Is there much diesel in the tank? Can you hear the pump under the passenger seat prime?

There's about a quarter tank in the car, it's not making any funny noises but I've not checked if it's primed - I'll go check that now. 

 

Seems strange how it was working fine, until I got the fuel filter changed - mind boggling how these things happen! 

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5 minutes ago, stew99 said:

Sounds like a fuel pump has failed. Is there much diesel in the tank? Can you hear the pump under the passenger seat prime?

Can't hear anything really near the pump, just about get a vague whirring noise - not too sure what I'm hearing for tbh anyway

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Put some more diesel in it just to make sure it's not the intank pump that's failed. Common signs for intank pump failure are air bubbles in the plastic feed line by the fuel filter and not starting from around quarter full and below. Once the pump is fully covered in the tank the under the floor pump can pull enough fuel on its own. 

If you put more diesel in and it does not start then that would point to the pump under the passenger seat failing.

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So pre-supply pressure is showing 0,31 bar regardless if the engine is running or not? What does it show when sensor unplugged and how does the engine behave with disconnected sensor? And there is no direct code for the sensor itself when it's connected? When you turn ignition on pos. 2 the pumps are activated for 60 sec if engine is not started. When fuel pumps are not active the sensor should show atmospheric pressure 0,9-1,0 bar. 

Edited by Clavurion

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1 hour ago, Clavurion said:

So pre-supply pressure is showing 0,31 bar regardless if the engine is running or not? What does it show when sensor unplugged and how does the engine behave with disconnected sensor? And there is no direct code for the sensor itself when it's connected? When you turn ignition on pos. 2 the pumps are activated for 60 sec if engine is not started. When fuel pumps are not active the sensor should show atmospheric pressure 0,9-1,0 bar. 

 

2 hours ago, stew99 said:

Put some more diesel in it just to make sure it's not the intank pump that's failed. Common signs for intank pump failure are air bubbles in the plastic feed line by the fuel filter and not starting from around quarter full and below. Once the pump is fully covered in the tank the under the floor pump can pull enough fuel on its own. 

If you put more diesel in and it does not start then that would point to the pump under the passenger seat failing.

Right guys I'm moving somewhere now, hopefully...

 

In response to Clavrion the pressure was 0.3 on ACC/ignition/and rev to 3000. I Just took the sensor out and I got the error code fuel injection on the Speedo. However the pre supply pressure went straight up to 4.0 and jumped to 4.36 at one point. There seems to be no problems with the car now, no loss in power at all. Drove it for 20 miles was fine. Plugged the sensor back in jumped to 4.2bar stayed over 4 for about a mile then slowly dropped and I lost power again - back to 0.3. Seems like it's a faulty sensor must have got knocked when the fuel filter was changed.

 

Stew99 I'll fill the tank Tomo and see what happens with the sensor of, of it makes any difference... Also there are no bubbles in the fuel lines at all that was the first think I checked. 

 

I'm going to leave the sensor off all day tomorrow, run it normally see if I get any problems. You guys think that's wise to do?

 

Cheers so much for your help!!!

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Update

Changed the fuel pressure sensor and everything seems fine (touch wood). Responsive and figures seem fine... Hopefully this is the end of my problems - pray for me

 

Pic is on idle. On drive the pre supply doesn't drop below 3.2bar but comes back up swiftly

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Hi All - Just wanted to ad my 2 pence worth to this post! Annoying when the post doesn't have a perm fix.

 

I had all the symptoms described above and after doing a whole lot of reading over the last two weeks I finally managed to cure the issue on my E39 530D SPORT MANUAL.

 

This is how I did it:

 

1 - Got a mechanic to read any error codes on diagnostics and the following came up:

 

P0404 - EGR Control

P1260 - Delivery Fuel Pressure Monitoring

 

I did the following:

 

Removed the EGR and gave it a thorough clean (was filthy with carbon build up) along with the MASS AIR FLOW METER (2-3 hours of elbow grease).

Changed the fuel filter and fuel pressure sensor (£130) (Very easy job).

 

However although this initially cured the issue it was short lived!

 

2 - Checked Fuses and fuel pump relay all good.

 

Did more reading and symptoms pointed to fuel pump:

 

3 - Purchased in tank electric fuel pump (£140) and installed with help and guidance of mechanic. Located under drivers side rear seat. Fairly easy task and lots of videos on you tube showing you how to! Thank fully all the horses are now back and although I did step 1 I, It was well worth it as the car is now driving much better, beautiful smooth acceleration revving to redline with no problems :-)

 

The smiles per gallon are back and the miles per gallon are up as well!!

 

Hope this saves someone some headache..

 

 

 

 

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Just to ad...

 

Before purchasing a fuel pressure sensor (sits on top of fuel filter) disconnect the existing one and drive the car. Do the same with the MASS AIR FLOW sensor to rule these out and possibly save you some money.

 

Thanks..

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Hi, that's exactly what I did. Took the sensor off and it worked absolutely fine, took the MAF off and made no difference so replaced and can happily day it's been fine every since, touch wood!!

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