I am currently in the process of getting my car fully running on MS. I have a 94 saturn twin cam w/ a stock power train and an MS2v3.57 controlling fuel and spark.
I have spent the past few weeks on and off trying to get the MS2 to properly control the stock ICM with no sucess. I have it idling nicely and I can drive it around, but it will only run using base timing (confirmed with a timing light). This was an assembled unit from DIY Auto Tune so I should have signal to control ignition from Pin36 (connected to spark output A D14)
I have it wired as such:
Connector 1 (C1)
PN#12084220 / 6-way but only 5 used
A- IGN+ (fused) 12 V switched
B- Not Connected
C- EST (timing signal from MS) pin 36 on the MS
D- IGN REF (to MS TACH input) - pin 24 MS
E- Tach (Optional) back to stock Tach
F- Bypass (5V applied by MS after engine start) w/ inline connector. (steady 4.92V coming from gray TPS wire)
Connector 2 (C2)
PN#12084415 / 5-way
A- CKP+ Yellow from CPS
B- CKP- Purple from CPS
C- CKP Shield (RF Gnd) (no wire here)
D- REF LO, Ground
E- GND, Ground
I have attached the current tune as well as a quick idle and rev data long. I have the advance at idle set to 20* to check w/ a timing light to see if it is working correctly, but no matter what my settings are, or if I have the bypass hooked up or not I'm getting a base 10*. I have also tried switching from using the table to using a set advance. Maybe I'm missing a jumper somewhere on my board? I have it set for VR sensor with ignition control(JP 1/2), w/ J1 3/4 jumpered as per the instructions, and nothing else. I have tried it w/ JP 2/3 and J1 1/2 jumpered as well. With the case open I can see that there is power to D14 LED.
Saturn ignition control issues, OBD1
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PunkboySL2
- MS/Extra Newbie
- Posts: 15
- Joined: Mon Mar 07, 2011 6:45 pm
Saturn ignition control issues, OBD1
1994 Saturn SC2 Turbo, MS2v3.57 - under construction
1994 Saturn SW2 T3 7psi, daily driven, MS2v3.57
1994 Saturn SW2 T3 7psi, daily driven, MS2v3.57
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billr
- Super MS/Extra'er
- Posts: 6828
- Joined: Sun May 15, 2011 11:41 am
- Location: Walnut Creek, Calif. USA
Re: Saturn ignition control issues, OBD1
See if the below helps explain it some. My understanding is that there are two "EST" signals, one charging/firing the 1-4 coil and one for the 2-3 coil. My belief is those two wires are logic-level "on-off" control of the coil drivers in the ICM; should be easy to control from MS. Essentially a couple of "smart coils" plus the synthesis of a cam signal.
"From the service manual;
Electronic Ignition (EI) System Description
The electronic ignition system on both single overhead cam (SOHC) and dual overhead cam (DOHC) engines provides spark energy to ignite the air/fuel mixture necessary for combustion. The powertrain control module (PCM) controls spark under all engine running conditions. The system components include: the PCM, electronic ignition (EI) module/coil pack, spark plugs, spark plug wires and knock sensor.
The spark dwell (On-time) and degrees of spark advance are dependant upon engine speed, manifold absolute pressure (MAP), and engine coolant temperature (ECT). The PCM can vary spark advance from 39 degrees BTDC to 3 degrees ATDC under all engine running conditions when no spark knock is present.
IGNITION CONTROL
The primary function of the EI module is to charge and discharge the coil packs based on PCM control. The PCM has 2 control circuits, one for the 2/3 coil and the other for the 1/4 coil. The PCM uses a high control signal of near 5 volts to charge up the coil and a low control signal of near 0 volts to discharge the coil. If the coil is charged and the control signal is low, the coil will fire through its secondary towers. The secondary voltage can reach a maximum of 40,000 volts.
The secondary current always travels in the same direction and in a series type circuit. For example, when the PCM fires the 1/4 coil, the current will flow out of the #1 coil tower, to the #1 spark plug wire, to the #1 spark plug, through the block, up through the #4 spark plug, through the #4 spark plug wire and back to the #4 coil tower. If one of the wires/plugs were to open, the other mating cylinder would still fire out of its coil tower because the circuit would be completed through the EI module bolts.
In order to determine when to fire a cylinder, the PCM uses the crankshaft position (CKP) sensor. The crankshaft has 7 machined notches, 2 of which are close together representing a double pulse. The PCM uses this double pulse to identify cylinder #4 top dead center (TDC). However, the PCM still has to identify whether cylinder #4 is on TDC compression or TDC exhaust. This is accomplished by the use of Compression Sense Ignition.
COMPRESSION SENSE IGNITION
Both the SOHC and DOHC engines utilize Compression Sense Ignition, which eliminates the need for a camshaft position sensor. The EI module has sensing circuitry that detects when cylinder #4 has fired on its compression stroke and relays this information to the PCM. The PCM can then correctly synchronize the fuel injectors for sequential fuel injection.
The EI module uses capacitive pickup plates located under the 1/4 coil to determine when cylinder #4 has fired on compression. These plates are used to differentiate the polarity and voltage amplitude difference between the 1/4 secondary ignition circuits. Since each coil tower is of opposite polarity and the waste spark (2-4 kV) generally fires before the compression spark (10-25 kV), the module can determine cylinder #4 compression. When the EI module detects a positive to negative polarity sequence and a high negative voltage spike, it will pull the PCM 5-volt cam signal circuit to ground. The PCM knows that cylinder #4 had just fired on its compression stroke when this transition occurs.
The EI module, however, cannot always detect when cylinder #4 has fired on compression. These occurrences include the following:
During deceleration
Very low engine load conditions when engine is running
If a secondary ignition problem occurs on cylinder #1 or #4
Too few cam pulses (cam signal circuit not being pulled to ground) are a result of decreased cylinder #4 secondary resistance or increased cylinder #1 secondary resistance. Too many cam pulses, cam signal circuit being pulled to ground too often, are a result of decreased cylinder #1 secondary resistance or increased cylinder #4 secondary resistance."
"From the service manual;
Electronic Ignition (EI) System Description
The electronic ignition system on both single overhead cam (SOHC) and dual overhead cam (DOHC) engines provides spark energy to ignite the air/fuel mixture necessary for combustion. The powertrain control module (PCM) controls spark under all engine running conditions. The system components include: the PCM, electronic ignition (EI) module/coil pack, spark plugs, spark plug wires and knock sensor.
The spark dwell (On-time) and degrees of spark advance are dependant upon engine speed, manifold absolute pressure (MAP), and engine coolant temperature (ECT). The PCM can vary spark advance from 39 degrees BTDC to 3 degrees ATDC under all engine running conditions when no spark knock is present.
IGNITION CONTROL
The primary function of the EI module is to charge and discharge the coil packs based on PCM control. The PCM has 2 control circuits, one for the 2/3 coil and the other for the 1/4 coil. The PCM uses a high control signal of near 5 volts to charge up the coil and a low control signal of near 0 volts to discharge the coil. If the coil is charged and the control signal is low, the coil will fire through its secondary towers. The secondary voltage can reach a maximum of 40,000 volts.
The secondary current always travels in the same direction and in a series type circuit. For example, when the PCM fires the 1/4 coil, the current will flow out of the #1 coil tower, to the #1 spark plug wire, to the #1 spark plug, through the block, up through the #4 spark plug, through the #4 spark plug wire and back to the #4 coil tower. If one of the wires/plugs were to open, the other mating cylinder would still fire out of its coil tower because the circuit would be completed through the EI module bolts.
In order to determine when to fire a cylinder, the PCM uses the crankshaft position (CKP) sensor. The crankshaft has 7 machined notches, 2 of which are close together representing a double pulse. The PCM uses this double pulse to identify cylinder #4 top dead center (TDC). However, the PCM still has to identify whether cylinder #4 is on TDC compression or TDC exhaust. This is accomplished by the use of Compression Sense Ignition.
COMPRESSION SENSE IGNITION
Both the SOHC and DOHC engines utilize Compression Sense Ignition, which eliminates the need for a camshaft position sensor. The EI module has sensing circuitry that detects when cylinder #4 has fired on its compression stroke and relays this information to the PCM. The PCM can then correctly synchronize the fuel injectors for sequential fuel injection.
The EI module uses capacitive pickup plates located under the 1/4 coil to determine when cylinder #4 has fired on compression. These plates are used to differentiate the polarity and voltage amplitude difference between the 1/4 secondary ignition circuits. Since each coil tower is of opposite polarity and the waste spark (2-4 kV) generally fires before the compression spark (10-25 kV), the module can determine cylinder #4 compression. When the EI module detects a positive to negative polarity sequence and a high negative voltage spike, it will pull the PCM 5-volt cam signal circuit to ground. The PCM knows that cylinder #4 had just fired on its compression stroke when this transition occurs.
The EI module, however, cannot always detect when cylinder #4 has fired on compression. These occurrences include the following:
During deceleration
Very low engine load conditions when engine is running
If a secondary ignition problem occurs on cylinder #1 or #4
Too few cam pulses (cam signal circuit not being pulled to ground) are a result of decreased cylinder #4 secondary resistance or increased cylinder #1 secondary resistance. Too many cam pulses, cam signal circuit being pulled to ground too often, are a result of decreased cylinder #1 secondary resistance or increased cylinder #4 secondary resistance."