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Weird boost/turbo issue, please help me diagnose!


Jim_1979

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This is the information the seller posted in his for sale thread...

 

"the only down side is the gas exhaust valve sticks when you first spool up the secound turbo , so if you like your car a bit loud then no probs but if your like me and just potter about in the car you might want to change it"

 

With the car, I also received a 2nd hand actuator.

 

This was my original thread querying how to fit the actuator...

 

http://www.mkivsupra.net/vbb/showthread.php?p=1893589#post1893589

 

 

Ok.... been for a meeting today 70miles away or so, so got to play a little to see what the problem is.

 

 

After the first time it hits 4k rpm and the second turbo kicks in the car gets louder (obviously).

 

But then once your driving around at 2krpm etc the car sounds different and quite droney.

 

I noticed once this happens there seems to be very little power/boost until 4k rpm happens again and the second turbo kicks in. It seems like after the 1st time the second turbo kicks in, the first seems to do very little.

 

I put it into "2" and put the foot down, the car accelerates slowly until it hits 4K rpm and the second turbo comes thumping in.

 

The strange thing is, if I go back to the car tomorrow the car is fine again, until the second turbo fully opens up.

 

 

Anyone got any ideas as to what is actually happening??

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From your description, I think the exhaust valve is sticking open so you're loosing boost as the exhaust is simply escaping through T2, which is not actually receiving any intake air until 4000 rpm. If it's the valve itself, then I think that is a bit of a bugger to replace. I think that if the actuator had failed or the hose had a split, then the valve would default to being shut rather than open. Try putting the car in TTC (easy - search on here) by swapping the hoses.

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Is it possible that the actuator is sticking, then after time unsticking?

 

I'm about to pop out in the car just now to see if turbo one is getting boost again.

 

If it is, something is sticking somehow, then returning back to normal after a period of time.

 

Failing that, I might put it in TTC mode to see what the difference is. TTC basically has both running in parralel am I right? So it should solve the issue until I get it sorted/go single.

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Ok...

 

I went out for a little drive this morning ad turbo one was back to working fine again.

 

But if I was to open up number two, it wouldn't be.

 

So is the exhaust valve sticking open, or the actuator? Or pressure tank problem??

 

Why would it return to normal after time?

 

IS there anything I should do/check before I rip the turbo's off? lol

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You have PM mate.

 

These are what came in the boot of my car, I was told the actuator was a replacement one.

 

My question is, what is the other part? Is it to go with it? My car had UK turbo's fitted a while back so I'm wondering if that's the old Jap EGBV or a replacement UK one to go along with the actuator?

 

image

 

image

 

image

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It looks exactly like mine, which is a J-spec,

 

I'm not sure if the UK spec turbos have different requirements than the J-spec I shouldnt think so,

 

I thought it was only the EGR valve that was different on the UK specs for the intake as well as the maf sensor

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Do you have to remove what he has of the turbo system until you get to the point of removing the valve?

 

no but its a barsteward to remove, I cant remember what order things get removed but I remember coolant in my face....and thats after I drained and removed the rad!:rolleyes:

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