Boost Problem I need help!!!!

[Gordon15734]

I have a 86 944 turbo. I have a manual MBC that i can turn al the up or down and will not change the boost level. I have a duel port wastegate, Lindsey chips, and the MBC. I cannot figure this out or havent looked in the right area. Please give me an idea where to look and what for. All parts are less then a year old. Thank you!!!

[rick13]

Well. Step 1. Check all boost related lines.

[BTERRY1]

Have you changed anything recently? Did you just install the MBC and problem started or is this a new issue on a car previously running fine. It is more than likely vacuum related. check all lines and report back.

[Gordon15734]

All new lines and hoes. I have it hooked up all year just never got around to figuring it out. All lines check out fine. No leaks.

[kdjones2000]

Well then either your vacuum wiring is incorrect, your waste gate diaphragm bit the dust, or maybe your MBC died?

Have you looked at Lindsey Racing's site for advice? I assume that they diagrams on how to hook things up.

Good luck, Keith

[Gordon15734]

Looked over it. All vacuums are correct. I have no idea how any of the two would be bad. How do i tell if they are bad. My car does boost to 10 but when i turn the MBC all the way down it goes to about 7, all the way up is 10 no higher then that.

[guru944]

Gordon15734;

Lower port on wastegate goes to manifold vaccum. Upper Port on wastegate goes to MBC out. and inlet pipe vaccume goes to feed MBC as your reference signal.

Use a mightyvac hand pump to check your wastegate operation.

MBC they go bad after a while (don't trust none of them...) Use a Greddy Profec B or Type s electronic BC for best control. Had mine for over 10 Yrs...You can tune in the boost response.
Later...