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Discussion Starter · #1 ·
Hello. My car (1991 9000 CD turbo automatic) has started to misfire (I think) when giving the car a lot of gas. The boost will rise up to the 2/3rds mark and then wont respond to throttle, if you keep pushing it, it completely loses power and starts shaking around a lot. It has started the same time as a few other problems. The car has a sticking idle when its at a stop (sits at 1200 and very slowly drifts down to 850-900), and it seems to be more sluggish at low rpms. Thanks in advance.
 

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Discussion Starter · #4 ·
Unfortunately Saabs are like hen's teeth around here. What exactly would cause the cassette to fail during load? I know that mine isn't in the best condition, but I'm wondering if theres something I could do to get it working properly again.
 

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Originally posted by FoeCom:
[qb]..What exactly would cause the cassette to fail during load?  I know that mine isn't in the best condition, but I'm wondering if theres something I could do to get it working properly again. [/qb][/b]
Good question, but I don't have an equally good answer. Can only confirm that my 9000CSE -96 behaved exactly like that before I replaced th DI cassette (125000km).
Unfortunately it isn't repairable unless you can dissolve the stuff which enclose the electronics.
 

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If you remove the DI cart from the top of the engine look for oil seepage from the cart. What usually happens is that one or more of the coils leaks and when you load the engine the leaky coil will not produce a full strength spark which causes a minor misfire.

Some of the carts are made from 4 separate modules which can be swapped if you have spares available (or so I have been reliably informed). Failing that its a whole new cart unfortunately. And if you still have the original cart in place then you will also need a new peice of cable as the later carts do not use a captive lead.

My MY96 DI cart went from no problems at all to a complete load of junk (major misfires, no acceleration, top speed of about 15 mph) in about 300 miles.

Steve
 

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What exactly would cause the cassette to fail during load?[/b]
When the engine is under load combustion pressures increase requiring more energy for the spark to initiate. The spark will take the line of least resistance and if your DI unit is old and leaky then the insulation may be breaking down so the spark occurs inside the DI, taking the easiest path to earth, or it may track down the side of the spark plug insulators if they are damp or old and oily. Either way it results in misfiring and reduced power.
 

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Discussion Starter · #8 ·
Wow thank you for the very informative responses. StephenA, did your car show signs like mine right before going into the symptoms you mentioned? It seems to be behaving itself for now, idle and response seemed to straighten up a lot after cleaning the throttle body (Or maybe I just don't want to realize I'm going to have to fork out $300 for a new cassette! )
 

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My misfire came and went for about a year before I decided it was too bad and replaced. If it behaves you could leave it a while, but remember, when it misfires it could be putting unburnt fuel in the cat, and if this ignites in the cat it will damage it.

Neil
 
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