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Discussion Starter · #1 ·
1995 Saab 900se 4 cyc turbo.

Hey y'all.
Here is quick back story.
Car would run but any time would get into the throttle (3k+ rpms) would have short hard stutter. This went on for about 7 days. Finally half way to work the stutter went from intermittent to frequent and at 1.5k rpms. I made it to work and decided to check if she would start back up. No go. Had it towed home.
The problems
Now the car cranks but does not fire. I was thinking DIC but borrowed a working one from the dealership and still same issue. So then threw a new CPS into the car. Still no fire. Have it hooked up to a TECH 2 and it is showing RPMS, Fuel pump on, Throttle on .... everything on. just not getting any spark. Flipped DIC upside down and grounded plugs to check for spark. None. Also sprayed some starter fluid into it. but still nothing.

She is not now or ever thrown any codes regarding this either. I don't know for sure if the stuttering issue on acceleration and the no start are tied together. But originally I was just thinking fried DIC.

I would greatly appreciate if anyone has any other ideas before i have to think about paying an insane amount of money for the SAAB Dealership to diagnose this one.
 

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Discussion Starter · #3 ·
Dic. Came directly from dealer and I had another one I had ordered. The plugs where not really wet but wouldn't even start spraying starter fluid directly into intake
 

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Check the compression of the cylinders. Hook a test light up to the different wires in the DIC connector, one side to the black wire, the other side to each of the other wires, while cranking make sure the light flashes when connected to certain wires.
 

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I would also check the throttle body it sounds like it's in limp mode and you will have to reset the throttle body also check the inlet pipe on top of throttle body to make sure it's tight
 

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Discussion Starter · #8 ·
Just replaced it with a brand new one. Dealer bent me over backwards on that for sure. 133$
 

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Discussion Starter · #9 ·
Say it is a fuel issue. Would there be anything to tell the ecm there is not enough fuel pressure and to not send spark. I'm at the point thinking that there is something that is deciding to tell the ecm not to send spark during the ignition sequence. I've been all through the wis and anything else I can search trying to find the steps to look at.
 

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if you replaced the CPS. tech2 shows cranking, fuel pump so on so on. it really sounds like a ground issue to me. check if you are getting power to the DIC. first by using the ground in the DIC connector itself, if you get nothing ground right from the battery and check all pins again. once with ignition just on, then again while a friend cranks the car. check the common grounding issues spot also. drivers side rear in the hatch, back corner, is a ground that gets rusty. this one will cause all kinds of funky issues.
 

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Discussion Starter · #11 · (Edited)
Ok, Checked grounding points under the manifold and in the trunk. all are ok. Also checked ground pin on the DIC and it checks out as well. Also fuel pump does prime when in the start position. Going to check for compression next.

Pulled the fuel line going to the rail. Cranked it over and barely sputtered out of the hose. Obvious fuel issue. Going to work backwards and go to the filter and see what kind of pressure is there. My question is, how does the ECM know that there is no fuel pressure. Am I missing a sensor location or something?
 

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The ECU does not generate a direct CEL for a failing fuel pump, blocked fuel filter or failing FPR. However, you might get an indirect CEL because the ECU can't put enough fuel into the cylinders to get a good A/F report from the first O2 sensor... Ron
 

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Discussion Starter · #13 ·
Put on new fuel filter the old one was shot. am getting fuel pressure to the rail (removed larger line and cranked and it shot out)
Does anyone know the steps that the ECU goes through pre-spark. something is not checking off.
 

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"The ignition discharge module is mounted on the camshaft cover over the spark plugs. There are four ignition coils in the ignition discharge
module, the secondary windings of which are directly connected to the spark plugs.
The ignition discharge module is supplied with Batt+ from the main relay and grounded at grounding point G7P.
When the main relay operates, Batt+ is supplied to the ignition discharge module, which converts 12 V to 400 V DC voltage which is stored in
a capacitor. The 400 V voltage is connected to one pole of the primary windings of the ignition coils.
Four trigger wires are connected to the ignition discharge module from Trionic ECM pin 9 (cyl. 1), pin 10 (cyl. 2), pin 11 (cyl. 3) and pin 12 (cyl.
4).
When the ECM grounds pin 9, the other pole of the primary winding for cyl. 1 will be grounded and 400 V transformed up to max. 40 kV in the
ignition coil for cyl. 1. Ignition takes place in the same way for cyl. 2, 3 and 4.
If there is an open circuit in the power supply or ground to the ignition discharge module, the engine will not start.
If there is an open circuit on any of the trigger leads, the cylinder concerned will not fire.
Ignition control
When the engine is started, the ignition timing is 10° BTDC. To assist starting at an engine coolant temperature below 0° C, the ECM will
ground the trigger lead concerned 210 times per second from 10° BTDC to 20° ATDC, producing a "multispark". This function ceases at
engine speeds above 850 rpm.
During idling, a special ignition control curve is used. Normal pre-ignition is approx. 6- 8°.
If the engine speed drops, e.g. when the radiator fan is switched on, the pre-ignition increases up to 20° BTDC in order to increase engine
torque and restore engine speed. In the same way, ignition is retarded and engine speed is increased.
Ignition control during idling compensates for rapid changes in engine idling speed.
When the throttle position moves away from idling, ignition control changes over to normal control depending on load and engine speed.
The Trionic system does not have a camshaft sensor. A camshaft sensor is normally required for sequential knock control and fuel injection.
Saab Trionic must decide whether cyl. 1 or cyl. 4 is firing when the crankshaft position sensor indicates that cyl. 1 and cyl. 4 are at top dead
center.
This is done as follows: one pole of the secondary windings of the ignition coils is connected in the usual way to the appropriate spark plug.
The other pole is not directly grounded but is connected to a voltage of 80 V. This means that there is constantly a voltage of 80 V across the
spark plug gap except at the precise moment when the spark is produced.
When combustion takes place, the temperature in the combustion chamber is very high. The gases are ionized and start to conduct current.
This means that a current passes across the spark plug gap (without creating a spark)
The ionization current is measured in pairs, cylinders 1+2 and cylinders 3+4. If combustion occurs in cylinder 1 or 2, the ignition discharge
module sends a Batt+ pulse to Trionic ECM pin 17. In the same way, the ignition discharge module sends a Batt+ pulse to the ECM pin 18 if
combustion occurs in cylinders 3 or 4.
If the crankshaft position sensor indicates that cylinder 1 and cylinder 4 are at top dead center and a Batt+ pulse arrives on ECM pin 17 at
the same time, the ECM knows that it is cylinder 1 that has fired.
When the engine is started, the ECM does not know which of cylinders 1 and 4 is in the compression position, and ignition consequently
takes place on both cylinders 1 and 4 simultaneously. In the same way ignition takes place on cylinders 2 and 3. As soon as combustion
signals arrive on pins 17 and 18 of the ECM, both ignition and fuel injection are synchronized to the engine firing order.
If there is an open circuit on leads wires to pins 17 and 18 of the ECM, no synchronization of ignition or fuel injection occurs, and knock
control will take place in parallel on cylinders 1+4 and 2+3. This does not have any noticeable effect on the operation of the system."
 

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Discussion Starter · #15 ·
Thanks for the info! Went through and did pin point tests on the connector to the DIC. I have ground and power. The main relay is working as well. Now when I use the Tech 2 to manually fire cylinders I get no power to pins 2 through 5. (cylinder 1-4) Whats the likelihood of the ECU going out on these cars? Could this of happened from the rough running circumstance and the old bad DIC shot back into the ECU?
 

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It could be the ECU, while not a common occurrence, it's not completely unheard of either. If you can swap in a spare ECU I would try that, would be a quick way to rule it in or out. Also double check all the wiring, etc.
Also make sure that the battery is fully charged and in great condition, often people experience problems from a low charged battery that is drained from extended starting attempts.
 

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Discussion Starter · #17 ·
Ya have the battery on the charger during tests and was charged over night as well. I don't have a spare ecu either. Visually checked all wires from the DIC to the ECU and all look fine. If it was one wire though one of the other cylinders would of at least shown power.
 
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