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Discussion Starter · #1 ·
So my Saab's DIC finally died. Against my better judgment I purchased the $150 replacement (BECK/ARNLEY Part # 1788418) off of RockAuto.com. The car is now an absolute crazy misfiring machine under "spirited acceleration", way worse than even the factory unit right before it died. Aside from random misfiring while at idle (seems to worsen significantly when I turn on the A/C at idle) the car otherwise drives fine under normal conditions as long as don't give it more than, say, 20-25% throttle. Any trip into the boost and the car immediately begins rapidly missing, stuttering and jerking as a result. Runs nice and smooth again as soon as I get off the pedal.

Anyway, the car has about 163,000 miles on the clock, OAI, downpipe, JZW stage 2 tune, fresh set of NGK BCPR7ES-11 plugs gapped to 1.02mm/0.045 inches and a regularly cleaned MAF sensor.

I've disconnected the battery already, thinking that perhaps there was some kind of adaptation in the ECU that needed to occur with the new DIC and plugs. Didn't seem to make a difference.

I read the spark plug thread and some people seem to be gapping their plugs around 0.35-0.39, much closer than what I currently have (my POS gapping tool only goes to .045 inches). I'm half tempted to get a better gapping tool and reduce the gap to see if that helps, but I hesitate because it never ran this bad with my last DIC when I went a bit too long between plug changes and the gap really opened up.

Can anyone think of anything else worth checking or trying before I send the DIC back? Geez, a $150 for a DIC... you know, after all the times in the past I've been burned by going the cheap route (not just with cars but everything), I really should know better by now, shouldn't I? ;oops:
 

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I'd look at wiring to the DIC, look at the connector very carefully, look at the wiring cluster that runs behind the valve cover, follow the wires from both 02 sensors, etc. I'd even pull the DIC, and check it's boots for damage, melting, etc. If you have a spare/old spark plug, with the car OFF and the DIC on it's back, stick the spark plug's nipple into each of the DIC's boots to make sure it's latching correctly. There's a spring thing in them that secures the connection to the plug. Sounds like a bad connection or a wire grounding out. Report back with results and hopefully it's something I mentioned.
 

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Discussion Starter · #3 ·
So I just ran to Wal*Mart and bought one of those coin-type gap checkers. Not ideal, I know, but it was sufficient enough for me to adjust my gap down to around ~0.036". I took the car for drive and immediately noticed a big improvement in terms of idle quality (both with and without the A/C on), no more misfires at idle that I could tell, and I can also push the car to about 50% throttle now without it acting up. Unfortunately, when I go wide open or even just push the throttle past the ~50% mark, the out of control misfiring still rears it's ugly head again. It's almost feels as if this module is 'weaker' than my last DIC, which I guess would explain why a shorter plug gap helped to some extent, yes?

I guess the next step is to do as you suggest, Pontious, and check out the DIC itself. I hadn't thought to check that. From what it looks like, having briefly stared down the end one of the boots yesterday afternoon, the only thing visible is a spring that appears to makes contact with the top of the plug. Hopefully I am wrong about that but it sure looks like the only contact point, near as I can tell. I will say that it definitely doesn't seem like it latches into place onto each plug when you place it on the valve cover, unlike like the stock DIC. With the stock DIC, I could push it down into place and it was pretty much latched in where it needed to be before I ever stuck a single bolt in it (I actually drove it once without any of the bolts holding it on without any issue). This new DIC however, has a mush engagement over each plug, with tactical feedback as the plug latches in. This new DIC on the other hand needs constant pressure on it while screwing in the retaining bolts.
 

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Most alternative DIs are complete tat. Can you borrow a known working unit to try? At least you will have a positive diagnosis then. My advice would be to buy a second hand unit. I've seen them change hands for as little as £35 in the UK.
 

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Discussion Starter · #5 ·
Most alternative DIs are complete tat. Can you borrow a known working unit to try? At least you will have a positive diagnosis then. My advice would be to buy a second hand unit. I've seen them change hands for as little as £35 in the UK.
I hate to say it, Doctor Ken, but I think you're right. I drove to work this morning without too much incident, but when I left to go home (the car had been baking in the sun all day, I don't know if this is temperature related or not) the awful misfiring at idle reared it's ugly head once again. I think I will try a known working unit, just to rule out the DIC.

My dad has a 2006 9-5. From what I can tell it is the same type DIC module. Can anyone confirm or deny that this will work?
 

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Discussion Starter · #7 ·
OK, so I've lived with this issue up until today (since 98% of my driving very rarely goes beyond 10 PSI boost) when I discovered that my car would not start at all this morning. I got off my lazy **** and grabbed the known-working DIC off my dad's 9-5 and gave it a go but the car still wouldn't start. I kept cranking for quite a while and eventually the car coughed and sputtered to life. I took a quick spin around the block and got into the boost a bit after the engine warmed up. Same sputtering/misfire as with my el cheapo DIC. I popped my old DIC back on again and the car starts again as usual. At this point I am going to rule out the DIC as the problem.

So if the DIC isn't a problem? What is the next logical step? The CPS?
 

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OK, so I've lived with this issue up until today (since 98% of my driving very rarely goes beyond 10 PSI boost) when I discovered that my car would not start at all this morning. I got off my lazy **** and grabbed the known-working DIC off my dad's 9-5 and gave it a go but the car still wouldn't start. I kept cranking for quite a while and eventually the car coughed and sputtered to life. I took a quick spin around the block and got into the boost a bit after the engine warmed up. Same sputtering/misfire as with my el cheapo DIC. I popped my old DIC back on again and the car starts again as usual. At this point I am going to rule out the DIC as the problem.

So if the DIC isn't a problem? What is the next logical step? The CPS?
I'd check the timing.
 

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harness on the DIC plugged all the way in with the clip locked in?
 

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Discussion Starter · #10 ·
I'd check the timing.
While I suppose it is possible that the chain could have jumped a tooth or two, I can't imagine the issue is timing because if the engine isn't idling, or running the A/C at idle or otherwise operating above ~10 PSI of boost, it actually runs pretty well and doesn't seem to misfire. I would expect the overall performance to suffer in all areas of operation if engine timing was an issue, yes?

harness on the DIC plugged all the way in with the clip locked in?
Yep, DIC harness is connected quite tightly, I was super paranoid about that, actually, and have checked and re-checked more times than I care to admit. ;oops:

I encountered a crankshaft speed sensor fault (I don't remember the specific code) a long time ago, it was once and only once and it never made it out of a pending state. That is the only reason why I am leaning towards the CPS at this point. The misfire condition occurs in a very rapid manner that you can clearly feel, I can't help but wonder if it is actually a fuel cut that I am experiencing, rather than a true misfire due to a failure in the ignition/fuel system.

Anything else worth checking while I am at it? Could the throttle body create this kind of behavior as well if it were on its way out?
 

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Could also be the CPS. A cheap 50ish dollar electromagnetic part easily replaced. It is on the bottom right hand side of the front of the block as you are facing the engine compartment. The heat seems to weaken the housing, causing it to crack and then allowing moisture to enter. Enough mositure can then cause a continuous to intermittent short. When that happens, the ECU loses track of the compression strokes and multiple random misfires occur. I discovered mine was failing in this manner immediately after having given the engine a bath. My experience has been the part is good for 60,000 miles to 129,000 miles, depending on your climate and use. As well, while its failure can throw a code it does not always do so (at least on T5).
 

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While I suppose it is possible that the chain could have jumped a tooth or two, I can't imagine the issue is timing because if the engine isn't idling, or running the A/C at idle or otherwise operating above ~10 PSI of boost, it actually runs pretty well and doesn't seem to misfire. I would expect the overall performance to suffer in all areas of operation if engine timing was an issue, yes?
These are Saabs, afterall, that we are talking about...anything is possible, lol!

Anything else worth checking while I am at it? Could the throttle body create this kind of behavior as well if it were on its way out?
I'll second Saaboheme's suggestion:

Crankshaft Position Sensor. It tells the ECU what is going on so the ECU can determine the firing order. It is essentially a Hall Effect sensor which is to say a magnetic to electric transducer.
They have a history of being subject to harness corrosion due to leaking fluids/set screws somehow mysteriously managing to work themselves loose.
 
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