Another 'Restricted Performance' post

[v8sruleok]

Hi,

I've owned this 2011 SDV6 since June last year and its had problems with Restricted Performance ever since. It has 176K on the clock now and the oil was changed 5K ago (Penrite C4). Without going into too much detail it's currently throwing up codes P006A and P0235 (twice this weekend). It also throws P1247 (Turbo boost low) regularly, and P0105(Map/Barometric circuit) once..., although these are not appearing at the moment. I've rigged a crude smoke machine and confirmed no leaks in the usual places. It has a brand new MAP sensor in it, and I swapped the MAFs around. An air leak on a plastic tube underneath the car near the front right wheel was discovered last week and rectified and whilst improving the condition has not resolved it. I am wondering if I should be looking at the 'sticky turbo actuator valve' possibility next?

I've read numerous posts about 'restricted performance' on this forum, still, any thoughts or ideas appreciated. Thanks, Mike.

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[Eric SDV6SE]

" Air leak on plastic tube" do you mean the intercooler hose? Check all intercooler hoses and clips, noting that under no or low boost pressure it wont show up a leak. Perhaps remove and refit, cleaning as you go to ensure a good seal.

Also check the o ring that seals the intake to the throttle body, these fail and cause RP faults that you describe. It normally seals at idle and low engine rpm/boost pressure (when doing smoke test) but under higher loads can dislodge and cause boost pressure loss resulting in MAF errors and RP events.

Re turbo, Try freeing up the actuator and lubricating the pivot. Getting access to the actuator drive is a PITA but maybe getting some silicobe spray in there xoyld help rhe servo motor and gear move more freely.


You say SDV6, so im assumibg the 3.0L sequential turbo engine. The air control valve between the primary and secondary can also stick, this one is relatively easy to access from underneath the front drivers side, remove and clean the actuator may also help.

Cheers

[v8sruleok]

Hi Eric,

Thanks for reply,


" Air leak on plastic tube" do you mean the intercooler hose?


No, its a small vacuum line I think, continues from a 'T' piece near right wheel and runs up the body to join the vacuum supply near top of motor.

The rest of the things u said I will start investigating this weekend. To be honest, I did have my doubts that the smoke I pumped into the motor wouldn't be under enough pressure to reveal all possibilities.

Cheers.

[LRD414]

....its a small vacuum line I think, continues from a 'T' piece near right wheel and runs up the body to join the vacuum supply near top of motor.
That could be the vacuum line to the solenoid that operates the secondary turbo isolation valve, which is the same valve that can be "sticky" for the 3.0L engine.

Restricted Performance Event (https://www.aulro.com/afvb/l319-discovery-3-and-4-a/253796-restricted-performance-event.html)

Scott

[v8sruleok]

Thanks Scott,

I believe that you may be right regarding this vacuum line. I'll have another look over the weekend to confirm. Looks like the damaged section of my vacuum line has been melted through, though I haven't identified the possible source of the heat that did it.

I've previously read the post linked below, but re-reading with interest. It's a slow process working through the variables but hopefully I'll hit the jackpot soon.
Thought is was the damaged vac line as the car immediately responded with full performance and no errors (something not seen in months) but unfortunately on the next drive it was back in 'restricted' again.

Cheers.




That could be the vacuum line to the solenoid that operates the secondary turbo isolation valve, which is the same valve that can be "sticky" for the 3.0L engine.

Restricted Performance Event (https://www.aulro.com/afvb/l319-discovery-3-and-4-a/253796-restricted-performance-event.html)

Scott

[v8sruleok]

I just thought I would come back & wrap this post up as the problem seems to have been resolved.

I gave up trying to fix this myself & put it in the hands of the pros. After much investigation around the routine stuff, the intercooler was removed and a small air leak was detected. A new intercooler was sourced & installed last week.

So far, after travelling 500km towing a 3T van in the south-west of WA I have had no faults arise. Fingers crossed.....we’ve got a lot of kilometres ahead as we’ve now started a 4 month road trip. Hopefully, these Disco woes of the past 11 months are behind us.

[DiscoJeffster]

Intercoolers are another common failure. A mate who owns a low km 2013 recently had one go too, and I’ve seen other mentions. They’re not as common as the manifolds though which are a ticking time bomb

[walahbro]

2011 SDV6 105000km on the clock, I had the restricted performance come up last Friday morning. Tried cleaning MAF's....that didn't work It turned out to be one of the three black nylon tubes that runs over the top of the engine and disappear down the left hand side between the fire wall and engine. One was rubbing against some electrical conduit. It was a a hard nylon vacuum line that I believe actuated turbo waste gate. Chopped out the section with the hole and pushed vacuum hose over both end to join, and the light was gone. I'd hate to have to replace one of these, mechanic mate told me he spent nearly a day to replace one tube.
I was lucky I could hear hissing coming from the nylon tube in the engine bay whilst engine was on, but it was still very hard to find, recommend a torch, for visual inspection and run you hands over the lines to feel for any holes, smoke might be a bit hard to use as the cooling fan on the engine creates so much wash. There is also a T-piece i am looking to replace as it is also rubbing through this is towards the front of the engine and probably the next to go.
Hope this helps......I will try to get a photo later.

[Eric SDV6SE]

Thanks for the post. I've spent considerable time on the engine with the main cover off just checking the routing and interfacing between all the various hoses and tubing. Ive tried to secure where I can whilst giving enough play to not bend or kink hoses. Zip ties are one of the best inventions ever. One hose I've found loose or problematic is directly under the throttle body. It is an air tube and has a non return in line valve in it. Valve works ok, but the ends of the valve that push into the hose are smooth, not barbed. With a bit of oil in the air lines, the smooth ends of the NRV can't grip the tube anymore. I've zip tied both ends of the rubber tubing over the fittings, no more leaks.

[disco4now]

I will add my recent one here in case its helpful to someone in the future.
I was towing 3.5T van Sydney to Coffs Harbour. Had restricted performance twice on the freeway between Sydney and Newcastle. Cleared the P006A code and continued. The next day continued to Coffs Harbour and had 5 more occurrences. The wife was clearing them as we went along in the end. I looked for the dreaded cracked manifold when it happened but they appeared OK. Unhooked the van and could not get it the fault, so only towing.

I put it in with Coffs Landrover and they diagnosed a crack around the first hose coming from the primary turbo.(see red arrow.) New hose ($516) plus fitting and no re-occurrence after.



151825

The hose with the end of a teaspoon showing the crack.

Now back from the trip, I have telltale oil that indicates a cracked left hand manifold is in progress, but that is the next story.

[Eric SDV6SE]

With regards to the first diagram, I've had the next hose down, the one closer to the intercooler replaced, on the primary turbo side. LRA noticed it had nearly rubbed through when they replaced the turbo. What it runs on I can't recall.

Re the photo, that looks to me like that hose clamp has been tightened way too far, plus the rubber looks heavily affected by oil. I changed my alternator out last month and to get to it had to remove the lower intercooler hose, I drained about 1/2 a cup of oil out of that hose and the bottom of the intercooler...I will now open that hose to intercooler join every oil change (10,000km or 6 months) to check.

[v8sruleok]

I will add my recent one here in case its helpful to someone in the future.
I was towing 3.5T van Sydney to Coffs Harbour. Had restricted performance twice on the freeway between Sydney and Newcastle. Cleared the P006A code and continued. The next day continued to Coffs Harbour and had 5 more occurrences. The wife was clearing them as we went along in the end. I looked for the dreaded cracked manifold when it happened but they appeared OK. Unhooked the van and could not get it the fault, so only towing.

I put it in with Coffs Landrover and they diagnosed a crack around the first hose coming from the primary turbo.(see red arrow.) New hose ($516) plus fitting and no re-occurrence after.



151825

The hose with the end of a teaspoon showing the crack.

Now back from the trip, I have telltale oil that indicates a cracked left hand manifold is in progress, but that is the next story.

Think that's the one that is hard to get at....the one people routinely avoid changing.

[disco4now]

5 hours labour, so might have been a bit difficult .