[itchychops]

I have a 1988 9000 Turbo 4 speed automatic SPG model. Lately it has developed a problem where the car shudders while accelerating at low speed. It is worse with a load - going up hill and/or with passengers. It feels like the wheels are square. It goes away after it gets to around 50 km/h and then runs smoothly on the highway. I have replaced the spark plugs, cleaned the rotor cap, balanced the front wheels, replaced the rotors, replaced the cv axles and changed the transmission oil. The transmission was replaced about six years ago.
Anybody have any ideas what is causing this? It's driving me nuts.

 

[BurnsSide42]

hit anything lately? Mine did that with a Tweaked Sub-frame. All better now with a new sub-frame, new front rotors and pads. Maybe all you need is an allignment... never know. I assume you have anough air in the tires... though, that doesn't sound to be much if any of your problem. Get under the car and peel back/un-screw the plastic under skirt to see the sub frame for any scrapeage or tweakage. Chek your half shafts? CV joints, ball joints? Not sure what else to suggest. Let us know.

 

[laurent]

I'm currently dealing with nearly the same trouble :
During acceleration, the car was vibrating, when stabilised no more vibrations.
Sorry, it's a 9k Turbo, 1988, as yours. I've changed my rotors and pads, both front and rear, balljoints, wheels balanced, and nothing goes better.
I've noticed that when I was turning really close at slow speed, a little vibe in the steering wheel.
In fact, it appears to be the inner cv joints, or named too companion flange, causing those vibrations. After dismantling, I have the confirmation of the trouble by finding big wear on the cups.
So, I'm currently changing the cups and the tripods both sides, with bearings, clips and everything. We'll see what happens. But it's quite a long course, and you really need a good torque wrench. As it was too expensive, I'm doing it by myself, as the parts cost already around 600 USD. But I can discribe you the course to have a look on your inner cv's, but remember, it's quite a job ! and greasy ! hope that helps !
Laurent

 

[Honza]

Hello,

I have the similar problem on my 900 SET. As I discussed with my friend (he is good mechanic) I've been told, that this should be worn steering silentblocks, or other parts, that should hold the wheel in correct possition. The thing is, that it stutter only when front of the car is relieving (while acceleration with load or passengers on higher speeds) - the weight on the wheels is decreasing, and then smaller forse is enough to shake with wheels.

 

[laurent]

So, I've finished the whole job : dismantling trans, recondition the driveshafts by cleaning and regreasing ( ?) the outer cv joints and change the boots, changed tripods, the two companion flanges ( called inner cv joints too ), the inner boots, the clips and the bearings. ( axle intermediate bearing and the one I found coming with the right inner cv joint when you pull it out off the gearbox ). The difference is REALLY noticeable, no more vibration on accel ( hard! ), no more vibes when cornering, everything seems to be smooth. We'll see if it lasts, but I think it will, as I was really carefull and CLEAN !
As I've upgraded already brake rotors ( zimmerman )front and back, pads, trans, changed the turbo, forge bypass valve, new plugs, partially new geabox oil, I would like to upgrade now the ECU. It's a 88 9K turbo, assumin it's an APC upgrade I need, wich one could I use for best results ? Anyway, the next step will be to buy a B202 engine block, complete, that I will recondition entirely, to get an "as new engine" back on the car.
Another question, is it normal that the sound when braking changes because of cross drilled rotors ?
I've got a few parts left : bearings, a few clips ( all new ), gearbox to companion flange seal, and a 2500 km used "performance bosh bypass valve ", a few rubber seals, that I would ike to exchange against a old 9000 ecu, so if someone gets intersted ....
Anyway, thank to all of you, because it's by reading the advices and the information on the several sites we all know, plus using the haynes ( wich is really NOT complete ! ), that I was able to do the whole job !!!!! What a course ! so If you have to make it and you don't know how to do it, I will transmit to any of you all the documents you will need. Keep on saabin !
Laurent and sorry if my english is not always well written ....

 

[ksowden1]

I'll bet you its the Driveshafts Jeff.

 

[CarlyKeith]

'been meaning to ask that question. Can you have driveshafts balanced and if so how much?

 

[mtbman333]

This is just a guess, and I'm not positive if it's correct or not, but I'd wager that your transmission's shift-points are off.
If you were to drive a stick, you need to shift when the engine is at around 2000 to 2300 rpm's with the 2.3 LPT. When going uphill, this range increases to around 2200 to 2500. If you shift to early, you end up driving the car in a range where the engine does not have enough power to maintain your rate of acceleration. In other words, you are 'lugging' the engine.
In my 95 cs, when I lug the engine, the engine boggs and shudders, making the whole car shake a bit. Like I said earlier, this is just a guess, but considering your older automatic transmission, your transmission may be mis-calculating shift times, producing ones that are too low, and consequentally making your car shudder, especially going uphills or under load. Check this out with your dealer. Good Luck!

 

[BurnsSide42]

shift at 2000!!! are you mad?! I always shift while driving in the eco way at about 2700-3000 rpm's and that is to me the ideal. If i am really gonna get on it tho, it's more like 4000-4500 rpm's

 

[mtbman333]

Well, I'll be the first to admit that I don't normally shift that low, I usually run well into the 4 and 5k range, but my purpose for those numbers was for demonstration's sake. I only shift that low when I need to be a bit more stringent about my fuel consumption.