Is this bad? mbc just installed...

ian2000t · #1 11-24-2011, 01:53 AM

Just installed my ball and spring mbc in the hose between turbo and waste gate. Its obviously worked because I can now get 15 psi instead of 10. But, the problem us above 15 the boost gauge goes crazy and bounces round to about 10 psi vacuum!

http://static.photobucket.com/player.../VIDEO1143.mp4

Any ideas??

ian2000t · #2 11-24-2011, 02:53 AM

The problem is definitely not the gauge either - I've just tried putting my finger lightly over the end of the hose to the gauge. Pushing plenty of air through, then all of a sudden nothing at all.

Could it be some kind of overboost limiter? Its a 1990 UK 760tic. There are boost lines running to 2 weird devices by the glow plug relay.

ian2000t · #3 11-26-2011, 11:25 AM

Had no one had this before when upping their boost to 15psi?

anders · #4 11-28-2011, 06:06 AM

Do you notice a power loss when the gauge drops? It sounds like you have a overboost valve somewhere. I don't know how the D24TIC's are but all the D24T I have seen have had a dump valve that dropped the boost if it reached over 12psi or so. If The D24TIC do have one it will be somewhere on the charged air piping.

ian2000t · #5 11-28-2011, 06:44 AM

Yeh, there is a power loss when it happens. I've disconnected the boost line to the gauge and you can feel suddenly boost stops coming through when it happens.

I think one of those devices in the picture must be something to do with it. I've read the dtic should have an overboost warning light on the dash, but nothing is lighting up on mine...

Think I should just disconnect them and try it again?

anders · #6 11-28-2011, 07:45 AM

I don't think it will be any of those devices you pictured. I'm pretty sure you will have a dump valve somewhere. Post some pictures of the intake, turbo inlet, and piping.