Misfire any thoughts

1. The dreaded Direct Ignition cassette (DI).

1. That is also a possibility. Try to knock gently on the outside and listen for loose material.

This is probably the a rubber pipes that transfer a pressure signal to a pressure sensor. You can diagnose that by listening for hissing air noises in the engine compartment. Fixing is an easy DIY job. I actually just cut off the split end and refitted.

NGK BCPR7ES-11, and do not even think of fitting any other plug type! The ignition/anti-knock system is designed around this plug.

(Driving 1993 9000 CSE 2.0 LPT 135k and still in excellent cond.)

in article 467ac7cb$0$31684$ snipped-for-privacy@news.zen.co.uk, Charles C. at snipped-for-privacy@dundee.ac.uk wrote on 21/06/2007 19:46:

So ... Direct ignition? Red cassette?

An air leak with increases with load or becomes apparent with a throttle blip and engine movement is always a tough one to track down.

Sounds like the DI cassette ... What do others think?

Sounds like the DI cassette :)

Are you a late victim of the recent lambda poisoning issue with fuel in the SE of England? It seemed that Morrisons and Tesco were the main culprits, but other stations did give out fuel which caused lambda fogging ... This was a good few months ago, but maybe you've not used your car much.

NGK ... Without even thinking about it!

Does someone live near Charles who could lend him a spare DI cassette to test out the theory? They're quite expensive and mentioning it to a garage would simply result in a swap, a large bill and possibly not fix the problem.

One trick is to pop down to Halfords, buy a can of carburettor cleaner, warm up your engine and spray the fluid over vac pipes, where pipes are clipped onto metal and any other union or orifice that looks dodgy. Spray into areas that move when the throttle is blipped. If the engine increases in pitch noticeably, you've likely found an air leak.

Happy hunting ... Come back with more questions if you have them,

Paul

1989 900 Turbo S

Of course Red :-)

This is my thought too ... I suspected it before I took the car to the dealer but ... at the time it did not (or I could not feel) the misfire when idling.

No. The fuel has been from Sainsbury's or Shell and in always super unleaded.

I do not know what is there ... but SAAB had said they were fitting some

3 point Champion plugs (I remember them around £25 at Halfrauds) which were good for 3 years or 36K miles (if memory serves me right).

I will ... I am in new territory.

A bad DI will throw a code in the computer. If you have misfires in there (not just rough running) I'd suspect the DI.

Replace the plugs with NGK's in the factory model. A Saab dealer should be shipped for putting anything else in. They should know better.

If it helps anyone out in the future.

On 2nd take all problems pointed to fuel starvation which could be caused by a vacuum leak (hence the engine would cut off fuel). The car became difficult to accelerate but reasonably happy to run with a few misfires at a steady load.

However, it was the Direct Ignition cassette that was faulty. On 2nd visit to the dealer they chanced that this was the problem. I had done

380 miles with the misfire. The catalyst apparently survived. I am happy to settle for half the SAAB Experience.

Regards Charles

1. Direct Ignition systems are also used by other manufacturers.
2. They last over 60k miles and replacement is a simple DIY job, in fact simpler than changing the air filter (which is tricky on a 9000).

Not sure what you are trying to say. Are you trying to defend SAAB? I have not complained. Sorry if I read your message the wrong way.

I am talking about symptoms and how to possibly diagnose the fault if someone has the same symptoms sometime in the future. Whether the fault is a good or a bad thing or if we should replace the cassette at 60K miles as a service item is not something I am passing comment on.

:-) Charles

I wouldn't go so far as changing the DI as a service item, but keeping a spare is a good idea. You can easily get them for 150 UK Pounds. I was once stranded on a motorway incline and had to be recovered on a lorry. That was very embarrassing, never happened to my FIAT.