Overboosting and No reverse

I just got a '94 Saab 900 Turbo and I have 2 problems. This is my first Saab and I don't know much about them or Turbos.
One is that under heavy acceleration, the turbo will constantly boost into the red zone and has to be cut off by the saftey switch. I have to partially give it gas to keep it just below the red zone by myslef. Isn't it supposed to not go into the red by itslef? Is this a faulty wastegate? Would engine pics help?
My second problem is that it won't go into reverse. Gears 1-5 work 100% perfect. I know you have to pull up on the shifter to put it in reverse, but still no good. When the lever is in the reverse position, it sounds like the gear isn't catching all the way. I get a whine/grind. Maybe the linkage needs adjusting? Or the gear lever isn't going as far back as it should? Any suggestions?

hello alfredo,i'm new to saabs and turbos also , but i have done a fair bit of research into this stuff, don't take what i'm about to suggest as gospel, but it may help.

Try cleaning your MAP(manifold absolute pressure sensor)

Try cleaning out your bpc valve(if applicable)with wd-40 (don't leave any in , just in case-blow excess out)

as you suspected it could also be the wastegate, it could be seized or screwed up some other way(not sure what you can do to fix, but a waste gate is not expensive to replace),SORRY I'M DAFT(I MEANT THE DUMP VALVE, not the wastegate,the wastegate is actually part of the turbo so will propably be expensive to replace,and i dare say , time consuming to fix!!!)the actuator for the wastegate could also be to blame if it is badly adjusted/broken/seized/disconnected

i cannot tell you exactly how to fix these things as i am yet to have proper tinkering time with my own car as it lost an idler pulley on it's first long drive and is still parked up elswhere and i can't get to it

anyway, i suggest that you search the web for info /walk throughs etc.(if you don't have anything to work with)- I got quite a lot of stuff (saved as web archive files on my pc, I think this is legal(sorry if it isn't)

Try taliaferro knowledge base as a starting search(i used google)when you see it, note the saab site that appears as a link along with it(if you used google)

let me know how you get on,as i'm pretty sure my car is overboosting also, i just haven't had time with it yet....


Just realised you have a 900 - i have a 9000 ,my recommends were based on that, but i think you should try searching the web anyway!

so it is trying to get into reverse, but it wont engage?

Exactly. Seems like it just won't catch.

My first suspect for the overboost was the BPC valve. Soon as I get a chance I'm gonna clean it out. It's not hard to remove, right?

Nah mate it's a piece of cake,just remove the three pipes(label them,so they go back where you took them off) you will, however, need a torx key/socket, if you don't have one it would be a good idea to buy a set , as these cars seem to have torx srews everywhere!!!(relatively inexpensive)
remove the electical connector, and remove the two screws securing it to the fan cowling.(if it is also located there on a 900(i have a 9000)

blast it out with wd-40/liquid spanner or other and give it a blow out and/or a shake.


job done....

ps. Now would be a good time to check the hoses aren't blocked/perished/loose.

One thing that may be worth a shot is a shift coupler, this can be a cause of some shifting bother if it is worn- but if it is only happening in reverse, i'm not sure how relevant this is,will look into it....

in the meantime i will try to find a useful link for you , if possible.

watch this space

ok, mate found a page that may be of use to you-

http://www.saabcentral.com/forums/showthread.php?t=64597

if this link doesn't work, try going to it using just the site and then find the forum page.
note the link nearer the bottom of the page , this has a procedure for tightening the gear linkage!!

Thanks 4 the link. I actually saw that before. I'm gonna try it tomorrow. I'm getting every single saab site into my favorites for as much research as possible. Thanks again.

Your welcome mate, and happy SAABing

let me know how you get on

===UPDATE===

Been searching around amongst some archives in my pc and (eventually)found this page, it took me a while to get you a link as i called it something when i saved it and couldn't figure out exctly where i got it from----the site is called automotive-links.com (many thanks to them for such a comprehensive set of links) i figure this will be invaluable for research purposes.

http://www.automotive-links.com/mak/saa/saa.htm

im glad that the problem may have been resolved, but posting links to other forums is agaisnt the rules..lets not have more of that