Thread: no boost?
View Single Post
mark houghton mark houghton is offline
mark houghton's Avatar
Join Date: Jul 2008
Location: Central Washington State
Posts: 3,894
Originally Posted by 5050racing View Post
Thanks for the help,sorry to repost didn't see how fast the topic dropped .Checked relays and switched with other one from up front,no change.You can hear it but just .2 boost.What is it like pulling waste gate apart? I do all kinds of work on the farm equipment and alike,1/4 midgets,dirt bikes,any help ahead of time will be nice thanks.
The relays I presume refer to fuel pumps and such? They won't have an impact on whether or not your car builds boost, unless you've got poor engine running performance due to poor fuel delivery or which case you would have other symptoms beyond no boost.

The WG is easy to pull off....4 bolts where it mounts to the exhaust, and the boost signal hose are all that needs removed. There's a big valve in there (looks just like an engine head valve) that's held closed against it's seat via spring tension inside the WG housing. If the valve guide is corroded, or the seat itself, not allowing the valve to fully close, then it will "waste" exhaust pressure that ordinarilly would be turning the turbo.

Try this: Stuff a wad of paper into the WG muffler (if installed) or the WG exhaust pipe, and start the car. If the WG is not sealing closed, it'll blow out that piece of paper when you rev the engine. And/or, you can bench-test the WG once it's off the car by applying about 15 lbs of air pressure and seeing if the valve opens...if it isn't already open indicating it's stuck.
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 09-22-2010, 01:43 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)