very low boost all of a sudden

[Bohrn]

Well, thursday going to work, just cruisin in town, I noticed alot of steam behind the car, but as it was raining out and the road was wet, I thought nothing of it. Then when I stopped, I noticed that there was steam from under the hood as well. Oh crap, I think. Being only a block or 2 from work, I slowly drive it there, being nice to the gas pedal, and coasting with the engine off when I could. Never did the needle go above the mark on the right of the temp guage, but it was within a needles width of it for a min or so.

When the tech at work looked it over, he found the hose that goes from the thermostat housing to the throttle body was broken. So he replaced that and topped up the coolant. Of course the upper I/C pipe was off, and the hoses to the BOV were off as well so that he could get at that area.

Car runs fine, but now there is almost no boost!! Only like 3-5 psi max!!

I have checked the i/c pipe hoses, and did tighten one down, and put a clamp back on the bov vaccum line, but still only very low boost.

I hope I havent cooked the turbo. But on the way to work that day, I did not boost much at all, and only near the beginning of the trip, then I ran into traffic, so it was a nice cruise at low rpm.

any ideas?? What could be causing this??

thnx

 

[alIan]

i would double check it again for boost leaks... esp. where the UIC pipe connects to the IC (hard to see area, assuming you still have a stock IC). Then if that doesnt work, check your turbo for shaft play, visible damage, etc.

 

[Bohrn]

yea, it is dark out, but I will take it all apart and put it back togeather real carefully. The guy who did the work is a very good mechanic and races at the track alot, but he is a small block chev guy, and doesnt know alot about turbo cars. He probably figured it was just an intake pipe like on modern NA cars.

I hope it is not the turbo, because I have no extra money right now, with christmas etc.

just had a thought, hence the edit.

How about the BOV?? Is it possible that it is stuck open?? Or maybe it has a hose in the wrong place, causing it to open when it should be closing??

I am also going to check for a rag in the ic piping just to see if Vince was having a little "fun"

If the turbo is shot, will it make any noises or have any visible signs of death?? I ask because it makes no wierd noises. That I can hear anyway, my exhaust is pretty loud when WOT.

 

[nine5raptor]

you should have a hose from the intake mani to the bov. to provide a positive pressure source under boost. without this, you would lose all of your boost.

 

[nine5raptor]

make sure your mbc is still hooked up properly and check the wastegate actuator to make sure the arm is still hooked to the flapper, otherwise all of your exhaust is going out through the wg.

 

[Bohrn]

hose is on the bov, but I have to check the wastgate arm. Its dark and raining pretty hard now Tomorrow morning.

thanx for all the help

 

[Bohrn]

to those of you who said "wastegate arm disconnected" I say "you are correct sir!"

that was it, no exhaust (or very little) thru the turbine, all out the tailpipe. It kinda hit me when I thought about the psi I was getting. 3-4. that is how many psi it creeps past what I set the mbc for

and what you guys said of course.

Thanx for all the help people, appreciate it.

 

[twistedtsi]

yea i was about to tell ya that it was the wastegate arm cuz it happened to me at the track the arm came off so i did a lil tack weld on it so it wouldnt come out no more

 

[Bohrn]

I think I am gonna drill a hole in the little rod that the arm goes over, then I can put a cotter pin in it and take it off if I have to.