Help!!! Blasted boost

[merlin's S4]

Yep sounds like a boost leak. You can probably forget everything else until you've ruled this out. So have you checked the hoses to and from the moisture trap at the back of the engine? They've a habit of blowing off completely. Most common boost leak is the short ribbed hose down by the intercooler. It usually splits near one of the ridges so isn't always obvious to see by eye.

[Drummer87]

Right guys.

As some will know I'm experiencing some issues with the running of my car.... Again

So to the start.

Cars been running perfectly since getting it back on the road. Had a problem before with a coil had played up causing similar issues.

So driving along having some fun on full wot then a bang (not sound wise but like hitting a wall)

The car just started limping, boost fluttering up to 1.2 then instantly dropping to 1 bar steady then 0.5 etc...

Parked up, tried the maf connector a few times and turning the ignition on and off a couple, as this seemed to cure my problem before temporally. But no luck this time.

So laid her up for the winter, and Martin (as2q) kindly pulled my fault codes.



So the hunt begins. To date the following I have done.

Removed coil cover and checked all sparks for tightness. Seeing since fitting new ones hasn't been back in to check the torquing. But all good. Removed a few to check condition but all good.

Removed wastegate cap, checked diaphragm, no splits on inspection. And the spring Wasn't broken. But further reading if wastegate was at fault I would be over boosting before the protection kicks in. (Maybe wrong on this one)

Removed air filter, cleaned it up nothing wrong in there. Checked maf and was nice and clean. Nothing covering the grate.

Checked over hoses for anything obvious pop'd off or massive splits. Reading up alot on urs4boy pages followed all the hoses and advice. Found one hose at the back of my inlet to be looking worst for ware. Doesn't feel to be leaking.

Removed passenger scuttle for the ecu. On first inspection I say the hose dropping down and thought maybe someone has stamped on it. But nothing wrong with all the vacuum lines.

Still needing to look at the moisture trap.

Needing to get a boost leak kit.

As I know everyone is going to say boost leak lol

I started testing the coils. As I'm convinced its coil related if not pos.

Idled the car and started pulling the injector plugs off one by one noting change in the idle. But everyone one I pulled just went rough.

Needing to remove the cover again and test the firing of sparks. If a plug has failed in a very short lifespan of a thousand miles. Or the coil!!

The DV is forge, and I read issues arising with them. Looks oily around the cap...

Drove the car tonight, and decided to eliminate this problem! so disconnected the N75 and was driving faultless at 0.4 mech boost. But when cruising say in fifth or sixth low revs felt what I believe was a misfire ever so often.

The car drives like this.. Haven't explained the symptoms fully.

So most of the time car is hitting 0.5 bar, if low down I can make the car reach 1.2 1.1 then holds like 1.0 but feels slow. When boosting it judders, it's shaking its just plain 5HIT. All this on Wot sometimes a quick judder on half when boost is expected.

I can hear with my exhaust there no over boost. This to me feels like the protection I have read.

I'm going round the bend now. Whom up in Aberdeen has a boost leak test and knows how to use it?? Beer as a reward

What to do now????

Check spark firing..
Defo boost leak test
Hit the car
N75
Change out coils for 1.8T loom
Buy all new hoses
Buy a new turbo
Buy some nice upgrades

But all joking aside needing some Divine intervention now.


here's one on me

Chris