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No Boost

T

TurboDred

New member
Joined
Dec 14, 2006
Location
BROOKLYN NY
Just replaced my 13C with a 16T and everything hooked back up real proper like. No visual tears in any hosing. Boost guage is showing 15hsi of vacuum in idle and drops down to 0psi on acceleration and might go up to a pound or 2 at best under hard acceleration.

I suspect that the waste gate is not closing...therefore no boost. This is my 91 780btw. I tried moving waste gate actuator by hand and it seems pretty stiff. should I be adjusting it and if so, how?

Turbo has been reclocked proper like as well and the waste gate actuator has been moved with a welded bracket so there are no clearance issues. Cat is not clogged although my 13C dumped oil into the exhaust as there was a lot of smoke coming out the exhaust the first couple of miles. Very little 95 miles later unless I maintaining over 3500rpm then there is still a little residual smoke but nothing alarming.
 
Youve got to try hard to move the wastegate by hand if your not accustomed to it, they are stiff. With some grunt you should be able to move it , extend the rod for open, shorten rod for close. Ie pull rod towards trunk and that opens it. You might could try unclipping the rod from the wg arm and see how much if any its off. I recal a photo here starting you should have to pull the rod half the diameter of the wg arm pin. Hope that makes sense. Basically you want some preload on the wg so it holds it shut.


Also boot leak test it, make a tester if you dont out if a Schrader valve and two pvc end caps, air compressor blah blah just google it
 
I still don't have boost after adjusting the wast gate arm actuator. i had a different exhaust note after adjustment and got up to 5lbs of boost fr a moment and then back to the same old no boost situation.
 
You could have a bent or binding wastegate flappah, or cracked turbine housing, or torn CBV, or binding in open position actuator.

Inspect CBV first, then close wastegate flapper shut and maybe hold it shut with bailing wiring and go for a drive and see if you boost to the moon!
 
You will be able to visually tell if the waste gate is sticking open. Verify the waste gate is closed and make a mark on the exhaust housing and waste gate arm. Go for a short drive and try to get the "boost/no boost" situation to occur again. Then look at the mark you made on the waste gate arm. Is it in a different position?

I think a torn CBV is a more likely suspect.
 
What wastegate actuator? The stock 16T actuator is only in the 2-4psi range since they use electronic boost control. You need an MBC to get the boost levels up, or a different actuator.
 
Like I said, bind that thing shut, takes 15 minutes, and go for a drive and see if you can hit 20 psi. ORRR just pull the three bolts to inspect CBV. takes under 2 min.
 
No! Boosting to the moon sounds like more fun. And that part can be a little greasy and unfun to change. First thing would be a smoke test, then cbv inspection. Little electric ratchet would slap those three bolts off in 30 seconds....
 
Thanx for all the positive feedback. I checked the CBV and its in perfect condition, firm diaphragm and spring is gud. Takes a lot for me to get 2lbs, of boost. Drove to NJ was able to get 2lbs max on the highway. I was wondering if a MBC would get me the numbers I'm Looking for...13lbs...for now.
 
I was tempted to use wire and then I thought about a spring also but I guess the wire would be the way to go. Any suggestions as to what is the best MBC from Amazon I should get seems like they have a wide array of controllers.
 
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Something mechanical, they are usually the same basic design (ball and spring valve) you can buy one of if your crafty can make your own. Ive made a half dozen over the years, from basic plans off the internet with home depot air compressor parts to "fancy" with stainless, a lathe and mill.
 
Ok so I just bought the parts needed to make a homemade boost controller. Gonna give it a go and see what happens. Where should I be installing it exactly...btwn the intake and the CBV? or before the actuator..
 
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