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I'll restated my opinions on the DI failure:
1. The bottom line is that for an ignition component, it is of suspect reliability. If you disagree, should you get stranded or suddenly in a situation where you lose power when needed, your opinion may change.
2. I don't buy into increased gap causing the failures. Ignition coils have primary and secondary windings, and typically the primary circuit receives a fixed amount of current to produce spark. I don't believe that through sensor feedback that the DI is sent larger current to produce a stronger spark, although it may well vary the spark duration. Someone mentioned that the DI "detects" spark ionization levels, I'm puzzled as to how this component performs any type of sensing. I would believe that through feedback from other sensor such as O2 that Trionic can sense combustion conditions and vary spark timing and perhaps duration.
3. When my DI failed, I removed the black plastic cover. Besides ignition coils, there are electrical components internal, most likely to include capacitors and ICs. These components like a stable operating environment, and high levels of heat are known to shorten their life cycle. There are numerous physics and engineering reports regarding this.
4. I think someone has established a seasonal correlation to DI failures base upon increased summer time heat. My Colrado SAAB dealer mentioned that according to SAAB, failure rates are higher in the mountain states. Higher elevations can cause engines to produce more heat, and also I believe lower octane levels (I now run highest octane) can cause elevated temps through retardation of timing, as will of course higher turbo boost levels(aero failures). I think all these factors effect DI longevity by bringing operating temps to a level which prompts DI failure. And it can certainly happen in cold weather, as the cold to hot engine cycles also contribute to component stress level.
5. When the OEM is remanufacturing these components, what does it tell you regards to the failure rate ? I think it would only be fair for SAAB to place additional warranty (to 100k) on this component. It's enough of a pain to get stranded and towed in. I will give credit to SAAB for replacing my DI out of warranty, the local dealership was pretty upfront about the failure rate of the component, and I think that bringing up all the other problems I've had with the 99 9-5 did not hurt my case.
6. All the other problems I can get over, I cannot with the DI because I believe that it is a flawed design from the get-go, and after 10, 12, or how many years of production it is still short on reliability. I wrote SAAB to voice my opinion, others may want to as well.
Doctor DI
posted by 198.81....
, Fri, 29 Nov 2002 18:49:16, Sat, 30 Nov 2002 15:38:38
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