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saffron

Eml/limp Mode Problem

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After 14 months, I have finally found the cause of my turbo over-boost and engine shutting down into "limp mode" problem; it was the vacuum regulating valve (VRV).

It seemed to work ok on the bench, switching airflow from the centre port to the inner (filter) port when de-energised, and to the turbo (outer) port when energised. But on the car it turned out to be partially sticking, holding the turbo in longer than necessary thus triggering a signal from the turbo pressure sensor.

I removed the plastic top of the VRV and found it oily inside. I degreased the spring and diaphragm inside with alcohol and reassembled using a smear of clear silicone sealant around the base to ensure it was airtight. Result is that the engine now performs as it did when new. A recent round trip of over 1000 miles showed no sign of any reoccurrence of the problem under any driving condition.

Since the VRV failed once, most likely at some stage it will fail again but at £288 for a replacement, I will hold off doing so until I have to.

My thanks to Anchorman and Codswallop for their guidance, and to the many other contributors to this and associated threads for their info which has helped me begin to understand how the turbo system works (but still not sure how the SCV’s fit in to it all)

Hope this info will help others.

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After 14 months, I have finally found the cause of my turbo over-boost and engine shutting down into "limp mode" problem; it was the vacuum regulating valve (VRV).

It seemed to work ok on the bench, switching airflow from the centre port to the inner (filter) port when de-energised, and to the turbo (outer) port when energised. But on the car it turned out to be partially sticking, holding the turbo in longer than necessary thus triggering a signal from the turbo pressure sensor.

I removed the plastic top of the VRV and found it oily inside. I degreased the spring and diaphragm inside with alcohol and reassembled using a smear of clear silicone sealant around the base to ensure it was airtight. Result is that the engine now performs as it did when new. A recent round trip of over 1000 miles showed no sign of any reoccurrence of the problem under any driving condition.

Since the VRV failed once, most likely at some stage it will fail again but at £288 for a replacement, I will hold off doing so until I have to.

My thanks to Anchorman and Codswallop for their guidance, and to the many other contributors to this and associated threads for their info which has helped me begin to understand how the turbo system works (but still not sure how the SCV’s fit in to it all)

Hope this info will help others.

Well done Saffron for getting to the bottom of the problem and full marks for perseverance :thumbsup:

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Saffron,can you take some photos, there is VRV? tips-warning remove/installing. with best regards.

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Saffron,can you take some photos, there is VRV? tips-warning remove/installing. with best regards.

Hi Mogui,

If you check out the post on this site (page 8) by bodgit-fixit-run on June 14th you will see a photo of the VSV and VRV. The VRV is the one circled in red.

I found it easiest to remove the air filter housing for better access to the two bolts that secure the VRV. Disconnect the electrical connector and remove bolts to free it and make a note of the hose connections.

With the VRV on the bench carefully prise away with a screwdriver the two metal clips that retain the black pastic top that has the hose connectors on it. After cleaning I found the tricky part was to reassemble it completely airtight which is essential and after several attempts used the silicone sealant and left it a few hours to dry.

Have now done more than 2000 miles since and have had no further reoccurrence of the problem, even when towing. It seems that the VRV is only one of several possible causes of this problem but hope this info helps

cheers

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