XSeries-forum

Hi all,
Around 3 months ago I purchased a 2005 X5 3.0D sport 6-speed manual and to be fair it's been great with only a few little niggles. It's done 82,000 miles will BMW service history until 2008 then service history with non BMW garage.

The issue I'm having is a bit odd and has only started since the really cold weather hit but this may be just coincidence. Basically when you start the car and begin driving all is fine and well but then the car will begin to hold back and becomes very slow to accelerate past 2000 rpm although if you're light on the throttle it can be eased past 2000 rpm. Also form a standing start the car does not accelerate as it should. If the car is then switched off and left for 5-10 seconds and restarted all is well again for the rest of the journey with no 'holding back' and the normal (quite surprising) performance is back.

A few of my thoughts and maybe some folks on here can either confirm or disprove:

1. I haven't found any documentation to suggest the fuel filter has been changed, my thinking is there could be a blockage that cause's a drop in fuel pressure and the car goes into a 'safe' type mode. When the car is switched off the blockage 'sinks' in the filter and the car is fine again?
2. Boost issue, intermittent fault on boost sensor causing car to go into a 'safe' type mode?
3. Is it possible to read the fault codes by bridging some pins on the diagnostic plug and reading a flashing dash light or does it require a code reader plugging in?

Any help or suggestions are greatly appreciated.

Thanks

Matt

hello mate and welcome to the zone. by memory im pretty sure someone else on the forum has encountered a similar problem, but your best bet is to get a diagnostic read on it.. it should come up with a fault code

it could be going in to a limp mod either by the engine or the gear box
you will nee to get it to some one who knows what they are doing with a good diagnostics system like autologic and know how to use it

where abouts are you?

if you need advise you can ring me on 07831 103030

I'd say that it is the High Pressure Fuel Pump (HPFP) as it sounds like the fuel is not getting to the engine as fast as it needs it. At 2000 rpm the turbo is spooling up and if the pump can't supply the fuel it needs for the increased air it will feel like it is holding back or limping. This also could cause it to go into 'limp' or 'safe' mode and thats why when you stop and restart the car it clears.


Turks.

Thanks for the replies guys, in response to some of the questions:

I'm on Anglesey North Wales so a bit of a trek from most people.

It's a 6-speed manual gearbox so I doubt this would cause the running issue.

I do agree with the fact it's going into limp mode the when restarted it comes back out of it although no dash lights on which i find a bit odd.
Also I agree with the possibility of fuel starvation but I'm not convinced its from the high pressure side as If this had issues I'd expect the car to have the issue all the time. I'm suspecting either low pressure pump or hopefully clogged fuel filter.

I'm getting the diagnostic done at the weekend so that might reveal something and I'll post up here once I've fixed the issue.

Interestingly I run a cheapo Rover 420 td and both vehicles are fed from the same source and it's developed a missfire as well. Difference being it doesn't have a safe mode so just missfires. So I'm also suspecting the diesel.

hi i have a 2004 auto with the exact same fault,pull off drive no power stop engine wait few seconds restart all back to normal, as soon as possible going to get the codes read and see what transpires but for now will put up with it as no real bother,be interested to see if we have the same fault though

[quote=""s14matt""]Also I agree with the possibility of fuel starvation but I'm not convinced its from the high pressure side as If this had issues I'd expect the car to have the issue all the time. I'm suspecting either low pressure pump or hopefully clogged fuel filter.
[/quote]

The Low Pressure pump sounds like it is doing its job as its only when increased / high volumes of fuel are required that it is failing which points to High Pressure Fuel Pump. Also the pump can just start to stick if it is on its way out which therefore you wouldn't have the problem all the time.

If you suspect maybe fuel then try topping up from a different Petrol Station.

Hopefully this will get sorted soon, problems like this are very annoying!


Turks.

Right then, diagnostic done and the intitial response is the reason for 'limp' mode is over boosting.The following faults were found from the diagnostic:

1. Heater plugs 1,3,4,6 faulty.

2. EGR fault requires further investigation

3. MAF Meter permanent fault

4. Charge air pressure monitoring tube permanent fault.

The first two faults disappeared upon clearing the faults and re-testing. Also the car has been starting fine in the recent freezing weather so i'm not too concerned about the plugs. EGR faults I'm not too sure about and wondering if the other two faults are contributing.

I have read somewhere there's a known issue with the MAF sensor? Can anybody confirm or disprove this?

Does anybody know the location of the boost monitoring tube so I can take a look myself and see if there's anything obvious.

Thanks

Ok, good you got that done.

There can be problems with MAF Sensor and probably around about the mileage you have too. You can check if it is the MAF by unplugging it and then having a test drive to see if you get the same symptoms. If it runs fine after doing this then simply replace the MAF and job done.

Check the pipes to and from the Turbo. If there is a split or something like that, it could be the reason your Turbo is overboosting to compensate for the lost pressure.


Turks.

just quick update on no power starting from cold problem,let it warm couple of minutes stop restart all fine then sometimes, stop set off again lot of black smoke,so this weekend changed air filter and breather,when removed air filter found it had been fitted badly,one side had not gone over the maff sensor but had been forced inwards i fitted a pipercross filter and since then the car has been faultless,can only imagine that the bent in part of the airfilter was not leting enough air past,also might bring up same fault if filter was blocked,just thought would pass it on

Hi there Matt. wonder if your sorted. pm me IAM on anglesey

regards dave