The Ace

Dont know how many of you actually saw my thread a couple of days ago about the sudden loss of boost and the swooshing sound from the engine bay in my TII
(https://www.rx7club.com/forum/showth...threadid=92846)
but things seem to be getting more serious

After replacing the broken plastic funnel which is right after the turbo (which has two connectors going to the BAC and the BOV), connecting everything securely and making sure that everything is nice and tight, I crossed my fingers and started up the car.

Left it to warm up, and when it got to operating temps, I pressed the gas. SAME BOOST LOSS, SAME SOUND. Boost gauge will move from "-20" towards the "0", but it will not go any higher.

Although when I went to the engine bay and gave it gas from the secondary mechanism, the sound seems to be coming from the airpump/turbo area

I immediately called the most well known RX7 mechanic in Athens (Rotary Beat) and told him the symptoms. He said that it must be an IC hose. When I told him that I just replaced the hose that was cracked, he said that the only thing remaining is the axle of the turbo, which must be broken

Is this true guys ? Am I looking at a busted turbo ? When I had the intake and IC off, I checked the primary turbine, and it seemed rock solid. No play whatsoever. Nice spinning, no touching with metal housing, nothing strange or peculiar.

Is it even possible ? Can a broken turbo spool up to atmospheric and then stop making boost ? Let me know fellas, I'm in a huge pile of **** right now....


I guess the fact that I adjusted my TPS and now idle is rock steady is minor....

BlackRx7

wow I have no Idea, good luck with it

hypntyz7

Busted turbo-manifold or manifold-to block gasket will cause this, the boost loss plus the noise.

emagdnim

Possibly check your BOV...just 'cause you never know..

Cheers!

check the lines going to the boost sensor... if the vac lines going to the sensor the car will only boost to i think 5 psi or less....

Aaron Cake

iTrader: (1)

Wastegate stuck open? Though that wouldn't explain the swoosh noise.

The Ace

Vac lines all seem to be good and in place. I have checked with CC and tried to listen for any hisses, but nothing. And the vac lines to the boost sensor are solid too....and the car does not go over atmoshperic, i.e does not boost at all....

BOV seems fine. Although I couldnt check it properly (with pressure gauge) visual inspection didnt reveal anything out of the ordinary.

Blown gaskets ? Hmmmm, didnt think about that.....could check it though, if its a possibility.

Wastegate stuck open: I thought about this myself as one of the possible causes, but I couldnt check of course without taking off the turbo.

Any one of you guys ever had a busted turbo on your hands ? What was its behaviour ? I thought that a broken turbo (broken means no axle) does not spool AT ALL, which means that the pressure never got off the vacuum levels....anyone had any experience with this situation ?

hypntyz7

IT is a very comon possibility...many turbo IIs suffer from this. it limits boost and makes noise. There are 2...manifold-to-block, and manifold-to-turbo

No you dont need to take it off. Actually, mine was stock open not long ago. My actuator rod came off the arm. IN the front is the wastegate actuator, and the rod comes out the back of it. FOlow it to the small arm on the turbo housing. See if it is connected. The rod holds it shut until the actuator decides its time to open, when it moves the rod and thus the arm to open. My rod came off at the arm, and the arm was flapping on its own,opening under load all the time. IT still boosted, but not much at all, and very slowly.

The Ace

OK, after getting the car up in the air, I've found that its either the exhaust turbine, one of the gaskets, or the turbo housing

If its one of the first two, cost and repair time should be minimum. If its the latter (brrrrrr....... ), then I'm looking at a new turbo housing (if I can find it), or a somehow repaired old one...

Since we will have the turbo off the car, I will also check the wastegate (it probably has a small crack, weakend actuator, or malfuctioning rod), because I have been leaking boost in high rpms ever since I got the Rex...

I'll know for sure tomorrow...hope its not the housing...

Hey, I try to look at it this way: at least I'll have an -almost- brand new turbo spooling mAd BoOsT


...oh and JimmyV13 and jspecracer: I guess I dont owe anyone 100 bucks it wasnt an IC piping after all...

jimmyv13

With the car up in the air, did you check the wastegate? I have been having boost problems and I found that my wastegate actuator rod was binding with the side of the wastegate causing the flapper to stay open at times leaking boost into the exhaust. Sometimes it would shut completely and I would have full boost again for a while, but it would bind again. I got to looking at the w/g and noticed it was not straight like it should be, the mounting bracket to the turbo was bent causing the binding of the rod. I bent it back as much as I could with my hand and now the rod moves freely and shuts completely. My fix was free......


Hey at least your car idles, mine refuses to.

The Ace

I'll check the wastegate anyway once the turbo is completely off the car. Work needs to be done anyway in that area, so I'll check everything

And about the idle: when I was fitting the new hoses, I adjusted the TPS (it was a bit off), set it to 1.00v and since then idle is perfect (well, for the 10-15 minutes that my Rex has ran since then ). I know that my engine is also perfect (8/8/8 and 7.9/7.9/7.9 front and rear), but I keep having these bitchy little problems...

Anyway, I'll know for certain in about 4 hours....*crosses fingers*