TD4 running issues under load

Hi All
I have a 2003 Freelander TD4 BMW diesel with an issue that's driving me mad !

It had a leaky High Pressure fuel pump (Bosch CP1) so I removed this and replaced the seals.
Everything seemed fine for a few days, however thereafter once hot and under load the engine will hesitate, EML will come on and it runs poorly. Switching off resolved the problem until hard acceleration again.
Diagnostic had thrown up : Low fuel pressure, MAF and fuel pressure regulator. All of these have been replaced including MAP sensor, fuel rail regulator loom, turbo boost control valve, inlet manifold clean etc all to no avail.

Seems to drive fine from cold even under load it's after around 20 miles and at temperature that the issues occur again, regular as clockwork.

I'm assuming either a lead is breaking down once hot creating more resistance or the high pressure pump refurbishment is causing the issue.

Any advice much appreciated
Cheers

Lee

Have you replaced the low pressure fuel pump and fuel filter?
Oh I and a few others don't like to refer to the later diesel as a BMW engine. I prefer to call it a TD4. The fact it's made by BMW is unfortunate.

Nodge68 said:

Have you replaced the low pressure fuel pump and fuel filter?

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Hi, Sorry yes replaced both of these with genuine. EGR is blanked too by the way. There's no smoke issues at all as well. Baffled !

Have you looked at the live data for both low and high pressure pumps? And boost pressure too?

Nodge68 said:

Have you looked at the live data for both low and high pressure pumps? And boost pressure too?

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I have yeah, both the low pressure and high pressure were quite a bit lower than they should have been. Can't remember the exact figures though. It was taken that the low pressure pump was likely at fault being unable to supply the high pressure one at the rate demanded. Not sure on the boost pressure. This isn't a code that flagged up however I did change the boost valve just as a precaution. I guess maybe it might also be the turbo vacuum supply valve as attached (just above the starter motor)

Something else which may be important is after a while of driving with the EML on and the vehicle hesitating/spluttering I believe there's an electrical type smell. This only happens once the car has started hesitating/EML and not before.

The item pictured is the EGR control valve.
Are all the vacuum pipes sound with no open connections.

Morning. I need to have a proper look at the vacuum pipes to be sure they're ok. On the 'out' on the control valve there never was a pipe and it used to run fine. I'm aware that the HP pumps can leak and then seal themselves when hot - maybe with a new seal kit installed when it gets hot it's restricting flow ? Just scratching my head and trying to guess the idea really. Don't want to replace the HP pump with another (as it was a bit of a pain) only to find it doesn't cure the issue.

If the out side of the EGR control valve is open, there will be vacuum loss during EGR operation. This can reduce the vacuum in the whole system, stopping the boost control working correctly at partial throttle opening. At full throttle, EGR operation is suspended, plugging the leak, allowing vacuum to build again. Your fault seems to be a reverse of what I'd expect, but no vacuum loss is helpful.

Hi.
Thanks for taking the time to respond - really very much appreciated. I Forgot to say at the beginning that the EGR valve has been blocked. It still has this control valve in place though

Lee Pitcher said:

Hi.
Thanks for taking the time to respond - really very much appreciated. I Forgot to say at the beginning that the EGR valve has been blocked. It still has this control valve in place though

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Hi Lee I have the same problem what was it in the end ?
Andy

Same issue on my Freelander TD4 2.0 2003 BMW M47 engine.
After replacing low pressure fuel pump, fuel filter, MAP sensor, MAF sensor, removing the EGR replaced by a by-pass.
Cleaned turbo, injectors, air intake manifold, ...
Tomorrow i will replace the common rail fuel pressure sensor which seams to be faulty and causing my MIL light to popUp and putting the engine in secure mode.
It seams to be a well known problem with Bosch fuel pressure sensors from the era.

After changing the hp common rail fuel pressure sensor and harness cable to ecu, same MIL light and P1190 code appear.
Now controlled the injectors, and seams that 2 of them to be returning too much fuel to the tank.
Invertigation now on the HP fuel pump and fuel pressure regulator, on the pump itself.
Hope it's the last part change.
BOSCH 0281002480