SaabCentral Forums banner

1 - 16 of 16 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter · #1 ·
I just bought a Saab 9000 Aero and it ran fine the whole trip home. When i got home, I took it on some roads I knew and beat on it. Damn its a nice car! I noticed that in second and third gear when i would give the car full throttle, it would shake due to the blow-off valve discharging pressure about 2 times a second while the clutch was fully out. I'm still getting boost through first gear and some of the others. Has this happened to anyone before? The boost/apc gauge got stuck. Would the gauge have anything to do with relaying the information to the computer? If anyone has any Ideas I would appreciate it.

Taylor
 

·
Registered
Joined
·
1,036 Posts
if your gauge is stuck there is a good chance the hose is leaking & theres a good chance it is common to the hose that goes to the dump valve. Dump valve needs boost pressure to hold it closed, i.e. replace hose to dump valve direct from the plenium chamber, or fix leaking hose to gauge = fix,s your dump valve
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #4 ·
When you say a dump valve, is that something in the diverter valve or the whole valve itself? i checked it out, there is only one hose going to the diverter valve and its kinda dry rotted. How do i know which hose is the one that goes to the gauge? If that was the problem, would the gauge still be stuck when the car is turned off? Because that is whats happening with my car
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #5 ·
I posted this in the worng section by accident.

I just bought a Saab 9000 Aero and it ran fine the whole trip home. When i got home, I took it on some roads I knew and beat on it. I noticed that the boost gauge was stuck at halfway and when i would give the car full throttle, the blow-off valve discharging pressure about 2 times a second. I'm still getting boost but not like it should. Someone in told me it was probally a vacuum leak to the "dump valve". This is my first turbo car, so I don't know that much about how the whole system works. I checked out the hose that goes to, what i would call a diverter valve and its kinda dry rotted. What should I be looking for under the hood that would explain either of my problems.

Taylor
 

·
Registered
Joined
·
1,171 Posts
there should be a black vacuum hose going into the dump valve. Dump valve is the same thing as diverter valve or blow off valve, the only difference between a bov and a diverter valve is, a bov dumps the pressure into the atmosphere where as the diverter valve diverts it back into the system. First make sure you have no leaks in the vacuum system, id suggest replacing all the vacuum hoses with the silicone ones genuinesaab offers. If it is dry rotted like you said you probably have a leak some where. Check the T plastic piece to make sure all the hoses are connected. They can wiggle loose after a while, When u say its stuck is it stuck in the middle or is it stuck on the left or right side?? if its in the middle a hose probably broke or came un done


GL
 

·
Registered
Joined
·
987 Posts
Go through and replace all the vaccum lines you can. Do it one at a time to not lose track of the routing. And check the one way valve in the line coming off the valve cover. Make sure it goes back in the proper direction. It should prevent boost from pressurizing the valve cover. It sounds like you boosted up and blew out a rotted vac line somewhere.
 

·
Registered
Joined
·
3,938 Posts
Good leak free vacuum and pressure hoses are essential for proper running of these engines. The Trionic (and APC before it) uses a computer to trick the turbo wastegate into receiving less boost pressure than is actually developed until the engine knocks. If the actual boost pressure is not communicated to that wastegate when the engine knocks you can get overboost which will trigger the safety overboost pressure switch which cuts out the fuel. Also, the dump or hooter valve must receive correct pressure signals constantly so as to avoid pressure waves building in the intake that can damage the throttle plate and also trigger the overboost safety cut out switch.


Fix ALL suspect hoses, make sure the plugs are resistor type properly gapped and of the correct heat range. Use the highest octane fule you can afford and hang on to the steering wheel when you open 'er up....
 

·
Registered
Joined
·
658 Posts
keep us posted i have the same problem and started to replace vacuum lines but no change (not all bad because they needed it anyway)...1996 aero
 

·
Registered
Joined
·
658 Posts
not trying to thread-jack (sorry thrice)...i'll just throw my symtoms out there to see if related at all....normal gauge reading at idle then under accel dips to vacuum but no boost
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #14 ·
I've been busy this week, but I'm going to work on it today and the weekend. I'll let you know what my results are. Disconecting the valve sounds like a good way to find the problem, but will that send error codes to my computer? Im trying not to take this to a saab dealership. Lol If it is the valve, my friend has one he can sell me for pretty cheap.
 

·
Registered
Joined
·
1,036 Posts
trice330 said:
I've been busy this week, but I'm going to work on it today and the weekend. I'll let you know what my results are. Disconecting the valve sounds like a good way to find the problem, but will that send error codes to my computer? Im trying not to take this to a saab dealership. Lol If it is the valve, my friend has one he can sell me for pretty cheap.
your alright ref: computor, it takes its measure from the MAP sensor on the bulkhead which should have its own independant hose coming from the inlet chamber
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #16 ·
I went out and bought some new vacuum lines to replace my old cracked ones. I rplaced all of them except the one going into the dash to the gauge. It fixed my boost problem, but a new one started. Ill put a new post up about that. Thanks guys for your help.

Taylor
 
1 - 16 of 16 Posts
Top