MadGrip

Amongst the many bits on my car is a type of boost controller, and no matter how much I open it up the car wont boost more than about 10 - 14 psi.

I've had a good look around this afternoon and found that the sensor that fits it the catless up pipe seems loose i.e. I can wiggle it about, but the actual bolt holding it in place is tight as a ducks ***, so tight in fact that I cant even undo it.

If exhaust gases are escaping from this sensor before reaching the turbo, am I right in thinking that this would cause some kind of boost leak ??

If so can anyone tell me what the sensor is & is it a subaru only part or can I save by going to the local motor factors ?

I've checked all the usual hoses, pipes etc for splits and all are ok

any advice appreciated.

the car is a MY01 WRX (bugeye)

Phil

MadGrip

anyone ??

Fizz_daz

the sensor in the up pipe on a bug eye is the exhaust gas temp sensor. that's all I can help with though!

MadGrip

Thanks FD ,but if its not seated properly and exhaust gasses are escaping from there, will that cause a loss in boost ?

Phil

highlander68k

I'm guessing here.....

The exhaust gases are on the turbine side of the turbo, and would probably leak pretty badly if it was this (?), and would be noisy if it was leaking. - Any noises?

To leak on the compressor side of the turbo can be difficult to spot if its only leaking when the boost is higher (unless of course it was on a rolling road).

You say you've checked all the pipes. Does that mean you've been there ensuring the jubilee clips are pretty tight? As I've seen this problem before.

How are you getting the reading for the boost - through the controller, ECU or a separate guage? And have you checked the pipes to these THOROUGHLY? Are you getting the readings from the higher gears? (Some people try to get an accurate boost reading from 1st gear! - honestly).

As the car isn't that old, I would guess (as I've not dealt with many newer imprezas )there isn't a problem with the wastegate, but nothings impossible.

That's all the ideas I've got at the moment.

MadGrip

Thanks for the reply highlander. to answer a few of your questions.

I've had every pipe off the car that dosn't hold any fluids AFAIK , filled them with water and twisted them in every direction possible, to check for leaks. Obviously cleaned and thoroughly dried before putting them back on.

I made sure everything was as tight as I thought it shoud be.

in first, boost seems fine.
2nd & 3rd it picks up ok, but never to more than 10 - 14 psi
4th & 5th at WOT is a bit of a joke as it pulses like hell.

I'm reading the boost from a gauge a dash pod.

noise wise, there is a wierd sound ( a bit like a lollipop stick on a kids bike wheel) but this has been the same since the decat. could this be the gasses escaping from the sensor ?

I'll be going to scooby clinic in a few weeks for my 30k service, so if I cant find the fault by then it looks like I'll just have to let their hourly rate keep building up untill they find it

phil

just to add, I wouldn't know the turbine side from the compressor side , even if it smacked me in the head

The_Judge

From what you've described, you may have 2 problems...

It wouldn't cause boost leak. As Highlander said, that's a problem associated with the compressor side of the turbo (or in other words, all the induction tract from your air box to your compressor inlet, the hose from the compressor outlet to the intercooler, and the hose from the intercooler to the inlet manifold).

If exhaust gas is leaking somewhere between the headers and the turbo, it would reduce the pressure on the exhaust side of the turbo, so the exhaust turbine wouldn't spool as fast, therefore boost pressure wouldn't build as quickly. It's effectively like having the wastegate permanently open a fraction (sort of). I'm not sure that a small leak would limit maximum boost though.

From your description of 4th and 5th gear boost, I'd have put money on it being your wastegate solenoid. But if you're using a manual boost controller, you shouldn't be using the solenoid. Are you certain the boost controller is set up correctly? Is the hose to the wastegate solenoid definitely plugged? What type of MBC is it...?

highlander68k

The turbine side is the rusty side

A interesting website: http://auto.howstuffworks.com/turbo.htm

MadGrip

Thanks for the info guys, I guess it'll be up to scooby clinic now to come up with the goods, but at least I'm armed with a bit more info.

Thanks again, and I'll let you know how I get on, with a new thread

Phil