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Power loss

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Wed Dec 18 2019, 08:28pm
Joined: Oct 05 2012
Member No: #1051
Location: Estella
Since a few months ago I had and posted a power loss due to a faulty fuel temperature sensor which literally drowned in diesel, I perfectly felt today I had the same symptoms.

I was in the motorway in my once every fortnight DPF regeneration session, revving up to 3200 when the cruise control suddenly disengaged and I immediately noticed the turbos were not working. Unlike my previous occasion there were no warning or service lights. Once I could stop and lock it, I opened and started it up again and abracadabra, everything fine again, turbos back in town and electrical gremlins all gone.

As I changed the sensor last time, and had to clear the service codes for the turbos to come back to life every time it happened before the repair, well, just have the feeling it might be something different (hopefully never happening again), and just feel curious about it. Ever experienced something like this? Any clue.

Thanks a lot and Merry Christmas.
Thu Dec 19 2019, 09:17am
Joined: Dec 19 2010
Member No: #320
Location: Bedfordshire
I've had a similar experience with a C6 2.2Hdi.

It was caused by a leak in the vacuum pipes to the turbo solenoid valves, old/brittle pipes I suspect no longer making a good seal. The ECU won't allow the cruise control to function in this situation.

I had a second fault with the solenoid valve Which reduced the turbo boost, so a new unit was fitted.

Both were inexpensive parts, £30-£40 each.

1 User said Thank You to Hattershaun for this Post :
 cruiserphil (20 December 2019)
Wed Jan 01 2020, 09:59am
Joined: Sep 20 2016
Member No: #2793
Location: West Mids
Just to back up the previous response, even if they are not the cause of your present problem, it is definitely worth taking a good look at all the vacuum pipes festooned across the engine. On my 06 year 2.7 a number of them were extremely brittle and broke as soon as they were moved.

Check also the function of the inlet manifold vacuum flaps. If either has a punctured diaphragm, it will lose vacuum from the system.

I suspect your best course of action is to plug the diagnostics in again and see what comes up.


Fri Jan 10 2020, 05:21pm
Joined: Jan 03 2018
Member No: #3382
Location: South
I've also experienced various power loss problems with my 2.7. These were caused by (initially) the fuel filter and one of the EGR valves sticking. The latter also gave the 'Depollution System Faulty" message and lit the Check Engine Light.

I've not had problems within the intake, but the agree that the vacuum lines can be a real problem - the constant exposure to heat cycling in parts of the engine bay with restricted air flow, mean they become incredibly fragile. Though in fairness, I've had this with various other cars too.

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