[Tim95aero]

105k mile 9-5 aero - full Saab history, manual 'box.
Changed plugs (NGK), DI (lightly used genuine Saab), fuel and air filters, cleaned MAF and replaced some crumbly vac hoses. Running 99 Ron super unleaded and have put a carton of redex through the tank. however.....
The car starts without issue either hot or cold but hesitates on full boost (between red and yellow sections of boost gauge) in 3rd, 4th an 5th hence help needed please! The boost gauge seems to indicate normal conditions (climbs to white/yellow join-presumably atmospheric-pressure on key to position 1 before starting and behaves as expected whilst driving).
Thinking a controller or sensor messing with timing or boost is the likely cause(?) as sometimes all is well - but where to start? I've checked the waste gate rod and all is still connected. I can't move the rod under light pressure (assumed normal?) - though the rod is a bit corroded. The waste gate sound is not obvious with windows up or down - but was driving an Evo 4 previously so noise levels in the cabin are different to what I've been used to...! Is this issue symptomatic of any other turbo system components (boost controller, dump valve...?) If i replace any of this stuff is it worth upgrading or sticking to OE? Also, I wonder whether a new crank sensor is worth a try? I have no record of this ever being changed. Are there any simple checks I can use to rule any of the above out (I'm reasonably capable)? Any help appreciated.
Thanks very much. Regards, Tim

 

[Tim95aero]

Re: Saab 95 aero - stutter / hesitation under load STILL present UPDATE

UPDATE:
I've done some playing about this morning. I have re-silicon greased the DI boots and all appears to be well with the DI and plugs. I've checked the dump valve is not leaking by blowing on the recirc line (no leakage). I've also taken the APC off (3 way boost control valve above the turbo) and checked compressor to waste gate is open - and recirc is shut. I've also tried sucking on the waste gate vac hose - no leakage evident.

Having done the above, took the car for a drive. As before stuttering still occurring. 1st and 2nd pull very hard all the way through the rev range, 3rd onward hesitation as before. Having found some straight and empty Tarmac, it looks like the boost gauge moves slightly into the red at full throttle in 2nd before dropping back to the red/orange border - change up and 3rd is very flat even though the boost gauge climbs back to the red/orange border.

I think I remember reading that boost is limited in 1st and 2nd(?) (how does a manual car know what gear it's in?). Given the boost gauge fluctuation and lack of performance in higher gears, could this be a fuel cut due to over boost from a failed/failing APC boost control valve? Help please!!

 

[jdke]

Tim95aero,
I have the same issue with my 01' 9-5 aero. Have you found whats causing the issue? I am going to keep searching the web and will let you know if I find anything.

 

[Tim95aero]

Hi jdke.
I ended up replacing the thermostat (reading fluctuated and was inconsistent).
The car was also smoke tested for leaks in the intake/turbo - but nothing identified.
I was also recommended not to use tesco 99 ron petrol.
However, although the car is better it still stutters at ~3-4k revs in 3rd, 4th and 5th.
Now thoroughly irritated with it, I just drive through or around the problem whilst looking for a replacement!
If anyone has any suggestions that might keep me in the Saab i'd be grateful...
Cheers,
Tim

 

[Paulq]

http://www.saabcentral.com/forums/showthread.php?t=222117

 

[Paulq]

Was it the wastegate ?

 

[Tim95aero]

Paulq,
The issue still isn't fixed. I haven't done anything to or with the wastegate. Would this cause the symptoms I'm suffering? I tried blowing down the hoses to and from the APC but couldn't get any air past the dump valve or wastegate. A previous Mitsubishi Evo 4 wastegate was obviously working as it could be heard from inside the car. I can't hear this one-but assume that's probably intentional given the type of car? Is there any other way to confirm?

I drove the car earlier and could generate the symptoms by booting the throttle, but when I tried gradual application to wide open throttle the car seemed to work ok. However, this might be a red herring related to engine revs as this problem only seems to reveal itself at ~3-4k revs. The boost gauge definitely climbs into the red then drops back to the border between orange and red at full throttle. Why would this happen and could it be linked to the problem i'm having? I'm keen not to replace every component that controls the engine for obvious reasons so any recommendation appreciated.

Cheers,
Tim

 

[Valhalla539]

I've been having the same problem. Fixed with NGK plugs.

 

[Tim95aero]

Update on this issue. I've recently completed the following:
-cleaned map sensor with elec contact spray
-cleaned boost controller as above
-wrapped the accessible PCV hose connections to the intake/throttle body with self sealing elec tape (noting that a small leak was evident just after the MAF at the PCV-intake connection.
This seems to have had a marked effect with boost restored to almost 100%. However, I did try blowing on the PCV line having pulled it out of the intake and I can blow past the non-return valve that is immediately left of the DI next to the head. Will the bolt mod to the boost control valve add any additional value? I also measured cps resistance - 877ohms, which seems in-band.
Any thoughts welcome.
Cheers
Tim