P38 DSE loss of power when driving

Fergie b said:

Afternoon everyone.
I was looking to hear from anyone who had this problem and resolved it.
I have year 2000 p38 DSE 2.5 Diesel, this used to happen now and again but now on every trip.
While driving the power is lost dropping to idle when you change gear or ease off on the throttle for a few seconds with engine check light flicker on, the power can be regained either by dropping a gear or letting it idle for a few seconds and throttle up again. It drives fine if you keep it at a constant RPM and starts and idle fine.
I have changed fuel filter ,tank fuel pump and also crank sensor. Vacuum hoses all look ok.
Any help would be appreciated,

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Datatek said:

Have you checked the MAP sensor? Try running with the MAF sensor disconnected. Check the needle lift sensor on injector #4 Check the leak off pipes at the injectors.
It really needs diagnostics, if the MIL is flashing briefly there will be a fault logged.

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Fergie b said:

Many thanks for your reply.
I just tried it there now with a short run up the road with the MAF disconnected and same issue, could this mean that the MAF could be faulty!!

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brianp38dse said:

The power loss and injector light flashing up can be the fuel quantity servo in the top of the injector pump going out of range, how many miles has the motor done.

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Fergie b said:

Thanks, The motor has 170k on it. The light that comes on is the engine check light and only for a second or two each time,
I am hoping to get a diagnostic check done at the weekend and hopefully will pin point something.

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Datatek said:

I have one where the MIL lamp sometimes flashes when lifting off the throttle, it has no effect on the car's performance so that might be a red herring. The fault it flags up is "fuel flow out of range" I'm led to believe that it's due to wear in the end stop for the fuel quantity servo.
Hopefully diagnostics will show where the problem lies.

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Fergie b said:

Thanks, The motor has 170k on it. The light that comes on is the engine check light and only for a second or two each time,
I am hoping to get a diagnostic check done at the weekend and hopefully will pin point something.

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Grrrrrr said:

If it is the original FIP then I would say it needs refurbing.

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Datatek said:

I have one where the MIL lamp sometimes flashes when lifting off the throttle, it has no effect on the car's performance so that might be a red herring. The fault it flags up is "fuel flow out of range" I'm led to believe that it's due to wear in the end stop for the fuel quantity servo.
Hopefully diagnostics will show where the problem lies.

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Fergie b said:

Hello again, a fault "fuel quantity actuator" showed up with diagnostic check, would you know how to resolve that issue.
Many thanks

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Fergie b said:

Hello again, a fault "fuel quantity actuator" showed up with diagnostic check, would you know how to resolve that issue.
Many thanks

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Datatek said:

I hope you cleared the fault. You could check the connector to the FIP is clean and the connector at the EDC, but I suspect if the fault keeps coming back it will be time for the FIP to be refurbished

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Fergie b said:

Looks like we might be on the right road to resolve the issue. It was suggested to me to try driving without the #4 injector sensor connected, and I did. The car drove perfect with the only issue been the engine light remaining on because of the obvious reason of the sensor disconnected. So I have ordered a new injector with sensor and hopefully when I install it the engine light will go out.
Thanks for everyone's help, I will post the outcome.

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Grrrrrr said:

#4 fine tunes the injection timing by moving the fuel quantity servo in the top of the pump. With it unplugged the car runs on default values taken from the crank timing. The new injector may just do the same but I guess it is cheaper than a new FIP so worth a try.

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