L494 3.0 Help needed

[TheHighlander]

As above, if my Focus RS exploding was not enough to tip me
Over the edge, the wife s RS is playing up.

2016 Sport 3.0 Diesel

It s had the EGR software delete and a stage one map for 20k or so

Drivers side inlet cover changed last year.

Other than that all good.

So restricted performance came on and I ve notice ld it s boosts fine to 3k rpm or thereabouts then gets sluggish and a bit juddering boosting.

Code - P0299-77 under boost

Tonight I did a smoke test and it s got a slight leak at the EGR actuator rod where it goes into the EGR.

The map sensor was a bit clogged so cleaned that, throttle body flap all good.

Cleared codes - Initially it will boost perfect the after it does it once it then does the same after 3k rpm so no boost.

I know the secondary turbo comes in at 2800/3k rpm so I m leaning towards a stuck actuator, I wouldn t go to say turbo failure as no smoke, blue smoke etc etc but I m no expert.

Next up I think would be to check the turbo actuator on the secondary turbo.

But open to all ideas

[mike_e]

We have this error on our diesel from time to time, usually during quick acceleration. Ignition off/on usually clears it otherwise I plug in the box and clear the codes. I was speaking to a local specialist about it during a recent brake pad change, his money was on the actuator having seen this issue many times. I think you're on the right track with your thinking.

[Otispunkmeyer]

These are parallel-sequential turbos. The second turbo as you know, drops in around 2800-3000RPM with decent load on and there is an actuator valve on the rear of the second turbo, but there is also a bypass valve somewhere round the front which also triggers at the same time to allow air into the secondary air path. I don't know if these are twin air box or one airbox with two hoses out the back. I've seen both, depending on vehicle.

We've seen it where the front valve gets sticky and either won't open or opens slowly which can throw a problem code if it doesn't actuate fast enough. We normally would see this when dropping down from high load mind you, where the secondary turbo was already working and the engine is trying to return to single turbo operation.

In our setup we can just clear the codes whilst the engine is running and its fine, the actuators worked, they just didn't get there in time.

The EGRs leaking a bit of smoke might not be a problem. Ours right now are howling, so there is gas escaping somewhere, and its not bothered. We have had boost pipes come off on the secondary side, turbo intake pipes come off the front of the compressor, splits in pipes. That side doesn't see much use relative to the other side so stuff just goes wrong through lack of use.

I'd guess by the juddering its got a bit of a secondary turbo switching problem, both actuators are vacuum powered I believe so have a check of those. We've never had a problem with the rear one, just the front. There is also a little solenoid on the front which as far as I can tell is for leaking boost away from the secondary airpath. That needs to be functioning as well but if that isn't connected it should shout at you almost immediately.