Hi my MY00 turbo2000 uk has developed an odd power surge when on boost after i treated the fuel system with redline SI-1 fuel system cleaner.

when you floor it at round 2k in a long gear like 4th or 5th its surges power on and off all the way to the redline, its really peculiar. it noticably loses power then picks up and loses it again

it doesnt do it in lower gears when the revs go up the range really quick though

any help much appreciated

 

Thats what mines doing mate, https://www.scoobynet.com/general-te...ver-boost.html

 

what exactly is 'overboost' and how can it be remedied? its only started doing it after i treated the the car with this fuel system cleaner which claims to get rid of deposits on the injectors etc. is it bad to drive the car with it doing this weird surging thing?

 

Is it a violent cut out (from your description I don't think it is), quite noticeable. If it is then this is overboosting and fuel cut (engine self preservation mode).

If it's more like you are gently taking your foot off the accelerator and then back on, then I suspect a weak wastegate actuator or faulty piping to it, very different from overboosting, in fact it's not holding the boost at all.

 

no its def not a violent cut, its like letting off the accelerator and back on like you say. are there any checks i can do to see if theres a problem? any way of checking the wategate actuator? could it be the dumpvalve?

and most importanly is it unsafe to drive the car in its current state as i have a lot of commuting to do in next couple days.

 

My problem sounds very similar to yours, like there is power for short bursts but then it drops to no boost and then back on again several times. I know it isn't fuel cut as this is like hitting a brick wall while in full pelt!!

If you do find out what this is I would be really interested to know. I was wondering if I had a faulty fuel pump.

 

any ideas chaps?

 

Right, this is exactly what mine is doing! Power like dimming out and back in sort of thing?

Its pretty much fine in low gears, 3rd, 4th and 5th are ****!

Id really like to know what it is, because its doing my head in!

It was doing it when standard, so it cant be due to any mods. All it has now is a blitz nur spec backbox, dump valve and panel filter.

Yet it still does it..

 

Well in your case you've ruled out a leaking dump valve as long as it's a good quality one that isn't renowned for leaking

You've all sort of answered the problem, you are losing boost. As the pressure builds up, all is well, then at a certain level, it leaks away as something isn't sealing correctly, exactly what the wastegate does.

Check all rubber connections from turbo outlet to intercooler, from intercooler to throttle body, and even the throttle body gasket.
All connections from the inlet manifold to where ever they go again for perishing. Imagine it like an inner tube on your bike with a slow puncture. Normally takes a few days to go down, increase pressure and it loses it faster.

If all is well here, then start to suspect the wastegate actuator itself, it could be getting weak in operation. Sometimes this can be associated with black smoke out the exhaust when it loses power as the fuel is there but no boost. Diesels show this more readily.

I don't think this is a majorly expensive fault to fix, nor too difficult to find yourselves with a bit of detective work. An old washing up liquid bottle with about half a cm of liquid in it topped up with water make for a great 'snoop' mix that when squirted around air connections makes bubbles if there is a leak Needs posotive pressure to do this so a few revs might be needed.

 

Its just odd that mine is a 05 blob eye wrx with only 26k on the clock.

Could the actuator fail after this long?

Ill have a look for an airleak tommorow after work.

 

yea im gonna do the same, ill keep u posted guys

 

the above sounds like great advice, and like Nick mentioned breifly in his first post (but is worth mentioning again!) add having a good look at all the boost control pipework including the T-piece to the list too. Sounds annoying as hell, hope you all get it fixed!
Ash

 

Boost control solenoid needs cleaning or replacing.

 

If it's a newer car, then perhaps an ECU fault or rather a duff input in the form of a MAP sensor? You'd expect some sort of CEL but from experience, this isn't always the case. If a sensor was to fail completely, then you might get an indication.

Checking of pipes etc though is free and can be done by yourself

Hopefully someone will come along who's had this problem and found a solution to it.

 

maybe you haven't read my above post

 

I have am having the same problem to, i have checked all the hoses, intercooler, vac hoses, cleaned the boost solenoid done one full 360 turn back on the actuator arm and no change, its doing my head in
It only seems to do it at high boost, if i put a map back on to the ecu with lower boost setting for example standard boost, it doesnt do it.

 

Maybe you posted your reply whilst I was writing mine. Didn't get a chance to read it until after the fact.

Good idea though

 

Not so much an idea, more of sorting the BCS has sorted the problem on a few cars I know that had the problem. Overfilling the oil can cause the problem, scoobs tend to like the oil at 3/4 on the dipstick

 

i will try cleaning this but where the hell is it?!? i have no idea as to where a boost solenoid would be! and clean it with what? i have checked all the hoses and there is no air leak.

also how do i adjust the actuator? as maybe it has worked its way loose perhaps?

heeeelp!!

 

also, how can overfilling the oil have an effect on the boost. just checked mine and it is slightly over the max.

 

Didn't mean to get your back up with the notion that it was 'just' an idea fella. I meant it purely as something sensible to try (it appear that all the recommendations given so far are falling short for some as well as the op).

Anyway, back on topic

Over filling the engine with oil will cause excess oil in the breather pipes and ultimately the intake. The boost solenoid valve will be on the drivers side attached to the suspension leg mount. One of the pipes from the bottom will go to the intake on the engine which is how it ultimately gets contaminated.

I'll be honest and say I forgot about this little beasty to check, mine doesn't use it.

Ideally you need some carb cleaner and spray it in each of the holes when the pipes are removed. It's basically an automatic bleed valve that opens and closes quickly keeping the boost level to within safe limits. If it's sticky, it might not react properly remaining open for too long (losing boost).

Do a search for boost control solenoid or control valve and all sorts will crop up about cleaning them etc

 

checked oil and over full :@

 

boost solenoid, over filled the oil. mentioned above, easy.

I guess brake or carb cleaner sprayed through it and allowed to soak for short period of time.

 

Where abouts is the boost solnoid? Do i need to clean it then?

 

Had a search but cant seem to find anything on new age..

 

ok now let me get this right, all i need to do is drain a little oil so it is just below maximum, (whats the best way of doing this so it doesnt go everywhere?!) and then spray carb cleaner down the boost soonoid?

once i have done these 2 things the car will be surge free? right??

 

No guarantees in this lark mate.

Can only suggest you try it and see what happens. Read what another post has put on this thread with regards to trying out everything suggested so far.

As for draining oil, unless you have a tube thin enough to put down the dip stick tube and use suction to draw it out, it's going to get messy. Removing the sump plug, letting some out and then refitting it means inevitable oil on the hands. I prefer it to moisturiser though

If the car is up for an oil change, then it might be worth doing it then, refilling carefully until you get the level you require.

 

unfortunately i did an oil change the other week so it def doesnt need another one, some im gonna have to get my hands dirty i think!

i have bought some brake cleaner and am going to do the job tomorrow after work, do i spray the brake cleaner down the tubes which go into the boost solenoid? as im guesing they will have oil in them because of the overfill of oil in the engine. and also to put the car in test mode do i simply connect together the 2 green plugs under the dash? do i need to unconnect any other plugs? i have read that if you do it wrong it resets the ECU

 

Resetting the ecu can be found in many places, here is one link:

SIDC Tutorial

When it says 'reset' the ecu, it means ridding the ecu of fault codes, timing etc, not the actuall map itself.

I'd clean out the pipes seperately, and then squirt a bit down the control valve openings. With the car is test mode, the valve should be operating which helps spread the cleaner about. The old deposits in there clog the valve up, it's this you're trying to clean out.

You may need to do it a couple of times, letting the cleaner dissolve the deposits in the valve over a day or two. Normal driving between times will be ok (apart from having to put up with your problem), but will help clean it out if that is the problem (fingers crossed it is).

 

Im going to try this today, can anyone tell me if the boost solenoid is in the same place by the left (as your looking at the car) suspension turret?

Because i am getting an odd fluttery noise when on boost, which i think is the boost solenoid..

Cheers.