Losing boost after 3000rpm

Posted: Sat Aug 01, 2009 2:58 pm

I got 4.2 turbo (DTS Kit) diesel GQ and im losing boost and power after 3000rpm every gear. Blows black smoke when it loses boost. Drops from 11psi down to 2psi. Not sure whats going on.

Joined: 29 Nov 2006 Location: Melb S/E

Check any rubber or silicone joiners between the air box and the turbo are not sucking in first.

Joined: 21 Mar 2009 Location: Cairns, QLD

Sounds like the waste gate actuator failing. Try disconnecting it mate. Have found the same problem on 2 different dts kits now.

It'll be blowing black smoke as it's still getting fuel and not enough air.

Joined: 19 Jun 2006 Location: newzealand

not sure about waste gate failing (wouldn't that increase boost?)

but common problems would be leaking hose/joins or high inlet restriction. blocked filter, plastic bag caught in filter etc, inlet hose/pipe collapsing under suction.

Joined: 21 Apr 2008 Location: New Zealand

gudday

No boost will drop the oxygen needed to burn the diesel so you'll get black smoke and very high exhaust temps.

waste gate seems the likely problem, gate spring more likely the suspect as minimum boost will be determined by the spring rate installed in gate itself.
Actuator just increases boost by lowering the pressure emitted on it.
Doubt its a air filter blockage as you say you can still pull 11psi of boost.

Also is the engine using oil???? maybe dropping oil into compressor side from Labrinth seal at 3000rpm????

interesting...let us know what ya find

good luck

Joined: 21 Mar 2007 Location: Mornington/ Victoria

I've seen soft intake hoses suck in and cause that, try removing the flexible ducting and going for a drive.

Joel

Joined: 02 Jul 2009 Location: Sunny Coast

Second that ^^ check your rubber ducting before doing anything else, common for them to suck shut at high revs if they are soft or worn.
cheers

Posted: Wed Aug 05, 2009 5:28 pm

Worked out what is was. I bought a filter sock that goes in the of the snorkel at the top. Took it out all good now. So thanks for your all comments.

Posted: Wed Aug 05, 2009 5:29 pm

Worked out what is was. I bought a filter sock that goes in the of the snorkel at the top. Took it out all good now. So thanks for all your comments.