Loss of manifold pressure under acceleration xf 2012 3.0d

Loss of manifold pressure under acceleration xf 2012 3.0d

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Discussion

slimmct

Original Poster:

18 posts

65 months

Monday 13th May 2019
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Hi, I have a 2012 model 3.0D xf. Yesterday, I approached an island at speed and accelerated hard out of the island. That was the point I heard a loud bang and gush of air. Thinking it was a blowout, I pulled over, but all looked good.

Pulling away though, as soon as the turbo kicked in, there was a popping sound and gush of air, followed by loss of power.

Under 3000 revs, the car drives normally. No errors. No restricted mode. Just under heavy acceleration, pop and whoosh.

I looked for a popped off hose or split hose, but nothing obvious. Trying again today, the turbo does seem to build pressure, but reaches a level where all pressure is suddenly released.

Hopefully, attaching the torque logging will show the manifold pressure climb with heavy acceleration, but suddenly drop pressure at around 2500 revs. Any ideas where the problem may lie?

fatboy b

9,566 posts

221 months

Tuesday 14th May 2019
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Cracked intake manifold or inter-cooler. Well known issues. Expensive to fix though.

slimmct

Original Poster:

18 posts

65 months

Wednesday 15th May 2019
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I'm open to it being a cracked intercooler, but it doesn't seem to match the historic symptoms. The engine idles without issue, performance is normal without boost , there are no restricted performance warnings.

Pulling away normally, there are no issues. Manually holding onto a gear, the engine will keep going up to red line with no impact to engine sound or performance. It is just under heavy acceleration, the turbos kick in at 2000 but almost immediately after, there is a sudden release of air and boost pressure drops, but no warnings or restricted performance. If you keep your foot down, the power loss remains, but lifting the accelerator appears to reset and you can put your foot to the floor again to the same effect. It starts to build pressure, but seems to immediately vent it.

It is in for diagnostics tomorrow. I'm hoping for a split hose, or waste gate fault, but braced for a complete set of intake manifolds.

slimmct

Original Poster:

18 posts

65 months

Wednesday 15th May 2019
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Phonecall from garage, it was the Turbo hose blown off. £25 and ready to pickup. I did not expect that.

anonymous-user

59 months

Tuesday 21st May 2019
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slimmct said:
Phonecall from garage, it was the Turbo hose blown off. £25 and ready to pickup. I did not expect that.
This sounded to me like a hose that forms part of the connection when the turbos go from sequential to parallel perhaps, so all is well until that switchover is made?

TDowney2394

535 posts

130 months

Wednesday 22nd May 2019
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Had this in my dads XJ. ZS soon as it got time for the turbos to kick in bang restricted performance. I managed to limp it back to Barry in South Wales which was interesting to put it lightlly! Swapped it for my then BMW 330D as we were supposed to be on a ferry that night! We made it just in time for the ferry the next day

jag21xj

3 posts

63 months

Wednesday 5th June 2019
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vacuum leaks