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Discussion Starter · #1 · (Edited by Moderator)
Recently purchase my first ever ST - first ever Petrol, let alone Turbo Petrol. In love with the thing..

Anyway. 2 weeks ago, giving it some WOT in third > into fourth, up to 5k when the power just dropped. Backed off - opened up Forscan, DTC P0299 logged! A recycle of the ignition will seemingly "reset" the issue. Decided to delve a little deeper, ran a log on a few things. Short story - on WOT, its losing around 4-6PSI of boost. Forscan logs show the wastegate operational. I got the car in the air Saturday - pressurized the intake system to 15PSI - there is no obvious leaks on the intake side. All VAC lines appear intact and secure. All clamps are secure.

- I am led to believe that the Boost Solenoids are prone to failure. The car has only covered 26k - 2016 model. Is it expected that one or both of them would of failed at this low-mileage? I was going to probe this as an option as its troubleshooting I could of done myself. However - it seems you cant buy the Boost Solenoids anywhere but the main stealers? And they want £189 + VAT per unit. I wanted to rule this out prior to it going to my local indie.

- Suspect to me is an invoice for a TurboSmart DualPort BOV installed in March 18'. I didnt even know there was a BOV installed in the first fortnight of ownership. Inspection on Saturday showed that it was set to its "hardest" setting. A quarter turn to the left and it was operational - for about a day. It seems to of disappeared again. Can this be faulty and the cause for a boost leak?

-Failing that, is the Wastegate Actuator a potential culprit? I wanted to leave Turbo investigations until last as it will be my local indie to remove and inspect - I trust them far more with the serious hardware (lol).

I will add that the idle on cold start-up is what I would describe as "lumpy". The rev counter doesnt really fluctuate and Forscan isnt showing massive variations once its settled. But its almost as if you can feel it "missing" under your seat rather than from the engine bay. Engine ticks over as I would expect when listening under the bonnet. You can pick it up from the exhaust note slightly. I am aware there is a technical bulletin for this from Ford - but I'm not paying £130 for a cold rough idle. I am told a step-colder Spark plug can help in this regard. Not sure whether this could be related - hence the mention!

Appreciate your guidance.

Jim
 

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Mk2 RS MP350
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If you are seeing underboost and have already checked for leaks, an aftermarket BOV would be ripe for suspicion.

I'd return it to stock.
 

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Discussion Starter · #3 ·

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Tangerine Scream ST3 2013, with some stuff done.
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Might be overkill on a standard car, but at least you know it wont give up too easily.
 

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Discussion Starter · #5 ·
Might be overkill on a standard car, but at least you know it wont give up too easily.
It won't be standard for long lol! I have a Milltek decat/turbo-back on order, RS Intake Housing and Intercooler will follow. So will be robust for future upgrades.
 
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