Following my list of 3 common Saab failures that will leave you on the side of the road, I wanted to discuss the direct ignition system found on your Saab. If you have a 9000 turbo (91-98), NG900 turbo (94-98), 9-3 (99-02), or 9-5 (99-present), then your car incorporates the direct ignition technology developed by Saab in the late 80's.
Direct Ignition... it just sounds fancy, right?
As you know (or may not know), Saab prides itself in turbo charging. Turbochargers increase engines efficiency by forcing air into the engine, which ultimately creates more power. By doing this, it is possible to make a 4 cylinder perform at the level of many v6 and v8 engines, providing not only power, but fuel economy (everybody say yeeeah!). The advances of turbocharging, and Saabs innovation with turbochargers, outgrew the performance and ability provided by distributor style ignition systems, so Saab developed the DI system to work with its new Trionic systems. The DI also cleans the plugs after you shut the car off. It runs through a 5 second burn off cycling, in which time it ignites all the plugs with very hot spark to clean the ignition surfaces of the plug!.
A Direct Ignition cassette, this one is red which indicates that this is a T5 systemWhat the DI system does is eliminate all of the common ignition components found on conventional ignition systems for a more... turbo friendly? ignition system. The ignition system is managed by Saabs Trionic software, which comes in two (technically 3) versions, Trionic 5 and Trionic 7. The MY93 9000's had a special version of T5 different from all others (94-98).
Also, for owners of 2003+ 9-3's, your Saab has a coil pack ignition system, which has 1 individual coil pack per cylinder and is operated by Saabs Trionic 8 system. I have yet to deal with this system enough to comment on any failure trends.
The DI system is housed within the DI cassette which sits on top of your engines spark plugs and ignites them with an electrical charge generated within the cassette. It is essentially a computer. It also can read knock and spark temperature through the spark plug itself, a capability distributor style ignition systems would never be able to incorporate.
Here we see the inner workings of a T5 DI cassetteNow, why is all of this important to you? These DI's commonly fail, and the vehicle will cease to operate immediately upon failure. The most common failure pattern I tend to see with them is an overheating of the small pocket of oil inside of the DI, which will then spill out into the circuitry. I'm not sure which comes first in this case, the chicken or the egg, but either it overheats and spills, frying the circuits, or spills from the circuits overheating.
What causes this?
No really, I'm asking you.
What I'm saying is that there is not really a common point at which these DI's fail. I've heard tell of a friend of mine putting on a brand new one from Saab, and it failing a week later. My 1994 9000 Aero made it 200k miles on its original DI cassette, yet some only go 60k. The DI is not a service item, and is never replaced by Saab unless it fails. I personally keep a spare on hand at all times in my trunk, because you really are at the mercy of it when you're driving.
A T7 Black DI, you can also see the boots which sit on the spark plugs
Replacing a DI is simple and only takes a matter of minutes, failures can often be identified by the smell that a DI puts off after failing, one of a burnt electronic nature. The lesson here is check your DI, there is a date code stamped on the label underneath. It will read something like 0250. The first two digits indicate the year, and the last two indicate the week. 0250 would mean a DI made in 2002 on the 50th week. Remember though, this does not indicate when the DI was installed, just when it was produced. If you have an older DI, I would suggest purchasing a spare to keep, just in case.
I keep both T7 and T5 used DI's on hand, price for T5 used DI's is $150 and $125 for T7 DI's. The two must not be interchanged, as they are meant to work specifically with the T5 or T7 system. As I already mentioned, T5 DI's are red and T7 are black. If any of you Saab-o-philes feel otherwise about DI interchangeability, this is not the place to discuss it.
However, this is. =)
There is also a recall on T7 DI cassettes, I will check your car for this during service to see if it has been done.
Anywho, I'll be doing some less common jobs over the next few days (vent flap motor on a 87 9000 Turbo with Automatic Climate Control, a transmission flush and filter replacement on a c900 automatic, and a Manifold Absolute Pressure sensor on a 9-5), I will post about all of that by the end of the week when they are completed.
Take care until next time,
-Chad
What causes this?
No really, I'm asking you.
What I'm saying is that there is not really a common point at which these DI's fail. I've heard tell of a friend of mine putting on a brand new one from Saab, and it failing a week later. My 1994 9000 Aero made it 200k miles on its original DI cassette, yet some only go 60k. The DI is not a service item, and is never replaced by Saab unless it fails. I personally keep a spare on hand at all times in my trunk, because you really are at the mercy of it when you're driving.
A T7 Black DI, you can also see the boots which sit on the spark plugsReplacing a DI is simple and only takes a matter of minutes, failures can often be identified by the smell that a DI puts off after failing, one of a burnt electronic nature. The lesson here is check your DI, there is a date code stamped on the label underneath. It will read something like 0250. The first two digits indicate the year, and the last two indicate the week. 0250 would mean a DI made in 2002 on the 50th week. Remember though, this does not indicate when the DI was installed, just when it was produced. If you have an older DI, I would suggest purchasing a spare to keep, just in case.
I keep both T7 and T5 used DI's on hand, price for T5 used DI's is $150 and $125 for T7 DI's. The two must not be interchanged, as they are meant to work specifically with the T5 or T7 system. As I already mentioned, T5 DI's are red and T7 are black. If any of you Saab-o-philes feel otherwise about DI interchangeability, this is not the place to discuss it.
However, this is. =)
There is also a recall on T7 DI cassettes, I will check your car for this during service to see if it has been done.
Anywho, I'll be doing some less common jobs over the next few days (vent flap motor on a 87 9000 Turbo with Automatic Climate Control, a transmission flush and filter replacement on a c900 automatic, and a Manifold Absolute Pressure sensor on a 9-5), I will post about all of that by the end of the week when they are completed.
Take care until next time,
-Chad
