This about sums up the procedure for replacing our existing DIS system with the older preobd2 DIS system, WITH part numbers (not guaranteed to be accurate)..
Megasquirt 4 cylinder DIS Compatibility/ Conversion and Parts Summary <UPDATED OCT 18 2005>
* unless otherwise noted, all references to Megasquirt are referring to PCB Rev 2.2
The following North American 4 cyl engines that use GM DIS are current directly compatible with Megasquirt rev 2.2 using MSnS-E.
These are to be referred to as “MSnS-E Compatible Engines.”
MSnS-E Compatible Engines
1987-1989 2.0 VIN 1 used in Beretta, Cavalier, Corsica Skyhawk, Tempest, Firenza
1987- 1992 2.5 VIN R/U) used in Fiero, Grand Am, 6000, Cutlass Ciera, Cutlass Calais, Celebrity, Lumina, Century, Skylark
1988- 1992 2.3 VIN A (LG0) Quad 4 DOHC H.O. (High Output) 1987-92 N Cars 1990-92 L Cars 1990-91 W Cars
1988- 1992 2.3 VIN D (LD2) Quad 4 DOHC 1987-92 N Cars 1990-92 L Cars 1990-91 W Cars
1992 - Only VIN 3 (L40) Quad 4 SOHC 1992 N cars (Grand Am, Achieva, Skylark)
1990-1991 2.2 VIN G used in Beretta Cavalier Corsica
1991- 1994 1.9 VIN 9 Saturn SOHC (Single Over Head Cam) w/TBI
1995- 1995 1.9 VIN 8 Saturn SOHC (Single Over Head Cam)
1991- 1995 1.9 VIN 7 Saturn DOHC (Dual Over Head Cam)
1992-1993 2.2 VIN 4 used in Cavalier, Corsica, Berretta, Century, Cutlass Ciera
1994-1995 2.2 VIN 4 used in Chevy S10 and GMC Sonoma
*Note* the term “VIN x” refers to the 8th digit of the Vehicle Identification Number which indicates the ENGINE CODE or VIN CODE for the applicable engine
These MSnS-E Compatible Engines have several things in common.
- All of these engines use GM Direct Ignition System (DIS) which is a “waste spark” ignition with a coil pack for each pair of mated cylinders.
-All of these engines use a 7X crankshaft reluctor with 6 evenly spaced notches 120 degrees apart and 1 “sync” notch 10 degrees after one of these.
-All of these engines use a 2 wire VR type crankshaft position sensor (CKP) which is mounted in a sealed bore in the engine block, adjacent to the 7X reluctor ring.
-All of these engines’ spark timing was controlled by a GM ECM/PCM using BYPASS>EST circuitry, similar to HEI 7-pin.
When the engine was cranking (or less than 400 rpm) there will be 0V on the Bypass circuit and ignition timing is controlled by the DIS module. After the engine starts (rpm greater than 400) the ECM applies 5V to the Bypass circuit, triggering the module to hand-off control of the coil primary circuits to the ECM via the EST circuit. The ECM controls the ignition timing advance and retard, as engine conditions dictate- in “next cylinder” mode.
MSnS-E Compatible Engines will immediately function with a correctly connected Megasquirt with full ignition timing control providing that the MS has the appropriate internal modifications. These modifications require re-routing the output circuits from the LED17 and LED19 circuits. The Megasquirt must also be running MSnS-E code, and have the appropriate changes made to the ignition settings in Megatune (See MSnS-E forums for more details)
ADDITIONALLY the ignition parts from most MSnS-E Compatible engines (*except VIN R/U) can be used on many newer engines (that share the same 7X crankshaft reluctor) and made compatible with the Megasquirt with full timing control.
These engines are referred to as “Conversion Candidate” engines
4 cyl Conversion Candidate engines
1996- 2002 1.9 VIN 8 Saturn SOHC (Single Over Head Cam)
1996- 2002 1.9 VIN 7 Saturn DOHC (Dual Over Head Cam)
1993- 1995 2.3 VIN D (LD2) Quad 4 DOHC (Dual OverHead Cam)
1993- 1995 2.3 VIN A (LG0) Quad 4 DOHC H.O. (High Output)
1993- 1994 2.3 VIN 3 Quad 4 OHC (SOHC Single OverHead Cam)
1996- 2003 2.4 VIN T Quad 4 DOHC
1994- 2002 2.2 VIN 4) “pushrod” L4 (LN2)
1995- 2002 2.4 VIN T) Quad 4 Twin Cam
2000- 2005 2.2 VIN F) ECOTEC DOHC L61
The Conversion Candidate engines all use a 7X crankshaft but have a NON-Bypass type DIS Module. These modules typically use 2 or more IC Control signals directly from the ECM/PCM, in effect they DO NOT have a traditional ignition module as it is "up integrated" into the ECM/PCM.For this reason these engines will not function with Megasquirt MSnS-E directly without conversion.
*Also Note the Quad 4 and Saturn DOHC engines listed above use low impedance (z) injectors and will require the injector flyback daughterboard to prevent damage to the Megasquirt injector drivers.
Basic Conversion Information
Each Conversion Candidate engine will require specific and differing alterations to make them MSnS-E compatible:
-In general these will always include REMOVING the oem ignition module and replacing it with one from almost ANY MSnS-E Compatible engine(New or Used)
On the Quad 4 "Candidate Engines" it is recommended to use the module with complete coil and cover assembly from a first generation Quad 4 (VIN A an VIN D engines) *Email me at firstname.lastname@example.org for the wiring schemtic as this engine combination has not been totally validated
-The connectors to the compatible module are often different than the candidate engine, requiring them to be cut off and replaced with the correctly wired compatible connectors. -In most cases the original waste spark coil packs can be maintained.
-Often the stock candidate crank position sensor can be maintained, although wiring to it may need to be altered.
-Some candidate engines such as the Quad4 and ECOTEC use Coil On Plug (COP) ignition systems, therefore a complete set of spark plug wires long enough to reach the DIS module, will be necessary.
-On those engines a suitable metallic bracket will also need to be installed to fit the DIS module and coilpack assembly. This bracket must be connected with a 12 AWG (3 sq mm) wire or braided ground to a clean engine ground point or battery negative.
Locating USED MSnS-E Compatible DIS components for Conversion
Use the “MSnS-E Compatible Engine” list as a guide for scouring your local Pick-A-Part and Wrecking yards. Note The 2.5L components may not always work with your application due to the integral design of the crank sensor used on some versions of that engine.
When you find a suitable donor take as much of the DIS system as you can :
-DIS Module and coils preferably WITH plug wires, mounting bracket and all fasteners
-DIS Connectors at the module
-Cut the connectors off with at least 6-12” of pigtail BUT try to keep the harness to the crankshaft position sensor intact! -it is a special “shielded” harness with a drain wire connected to terminal B of the 3 way connector at the DIS module.
- DON’T LOSE THE RUBBER SEALS ON THE CONNECTORS
-Salvaging the crankshaft position sensor is generally unnecessary as a candidate engine should already have one (and it may be different)
* I personally have robbed dozens of these from various wrecking yards and have paid anywhere from $1 to $100 for these components depending on their age, condition and the mood of the goof at the cash register.
** Whenever using “recycled” DIS modules and coils it’s a good idea to remove the module and coil packs and carefully clean any corrosion that exists at the module and coil mounting points. Remove any corrosion or oxidation with a bit of Scotch-Brite or steel wool. Clean any corrosion on the coil and module mounting bolts with a wire brush or run the correct die over the threads. Rinse all grease and oil from the DIS parts with contact cleaner or BrakeCleens.
This little bit of extra work is well worth it as will prevent misfires and erratic performance caused by high resistance and/or shorts.
Purchasing NEW MSnS-E Compatible DIS components for Conversion
Often someone putting together a new Megasquirt installation will not wish to compromise the integrity of the installation with used parts. By using NEW parts you not only get a warranty, but you also eliminate potential headaches caused by faulty used components. *Remember it was in an accident, it may LOOK OK but still be DOA!
For this purpose I have compiled a list of AC DELCO components used on the MSnS-E Compatible Engines. Remember, I’m NOT a partsman! I believe them to be accurate but cannot accept any responsibility for the accuracy of these part numbers that I have taken directly off of AC DELCOs on-line catalog at:
4 cylinder DIS Components for the following MSnS-E Compatible Engines
Instructions:Choose any one of the 3 applications below and order ALL associated parts (DIS module, connectors, brackets etc) for that application. Feel free to use ANY parts source (you don’t need to use AC Delco) The only real practical difference between them is the connectors used, and maybe the mounting. There may be some undocumented differences in current limiting and/or bypass advance levels.
Heck, that’s what we’re here for right??
1992-1995 2.2L VIN 4
DIS Module- AC DELCO PN# D1996A
Alloy Bracket for D1996A – PN#10495161
DIS Coils for D1996A- AC DELCO PN# D555
Harness Connectors (3) for D1996A:
C1 AC DELCO PN# PT787 (6-way)
C2 AC DELCO PN# PT782 (3-way)
C3 AC DELCO PN# PT1798 (2-way P2S)
1987-1991 2.0 VIN 1, 2.2 VIN G
DIS Module- AC DELCO PN# D1927A
Alloy Brackets for D1927A – PN#10495161
DIS Coils- AC DELCO PN# D555
Harness Connectors (3) for D1927A:
C1 AC DELCO PN# PT787 (6-way)
C2 AC DELCO PN# PT782 (3-way)
C3 AC DELCO PN# PT205 (2 way “L” shape)
1988-1992 2.3 VIN A,D,3 Quad 4
*Parts to convert 1993 and later "Candidate" Quad 4 Engines to "MSnS-E Compatible" DIS Ignition
DIS Module - AC DELCO PN# D1935A
DIS Coils - AC DELCO PN# D563
Harness Connectors (2) for D1935A:
C1 AC DELCO PN# PT701 (11-way)
*May be able to use existing 11-way connector WITH REWIRE
**May also wish to change Cam Cover Assem to older style
10497610 VIN D Embossed " 16V Quad 4 DOHC "
10468402 VIN A Embossed "High Output 16V Quad 4 DOHC"
10470589 VIN 3 Embossed "Quad OHC"
1991-1995 Saturn 1.9 (all variations)
DIS Module: AC DELCO PN# D1950E (2 connector style)
Alloy Bracket for D1950E – NPN
DIS Coils- NPN
Harness Connectors (2) for D1950E:
C1- Saturn PN# 12084220 (6-way)
C2- Saturn PN# 12084416 (5-way)
The Saturn Compatible DIS Module has only 2 connectors as the CKP sensor is incorporated into the 5-way C2 Connector (see schematic)
*NOTE* All DIS Mounting brackets must be GROUNDED to the engine block or B-
Crank Sensors - It is generally recommended* that you install a NEW Crankshaft Position Sensor in the “Candidate Engine” at the time of conversion.
*WARNING – If the old sensor will not pull out from the block easily LEAVE IT IN. These sensors have been known to break if too much force is applied during removal. Sometimes the broken end can be removed from the block with a small screw in dent or seal puller. Worst case scenario is having to pull the oil pan or even the crank to extract the remains of the sensor.
Crank Sensors for “Candidate 4cyl Engines”
1989- 1992 2.3 VIN A: AC DELCO PN# 213-970
1989- 1992 2.3 VIN D: AC DELCO PN# 213-970
1992- 1994 2.3 VIN 3: AC DELCO PN# 213-970
1994- 2002 2.2 VIN 4: AC DELCO PN# 213-235
1995- 2002 2.4 VIN T: AC DELCO PN# 213-970
1996- 2002 1.9 VIN 8: AC DELCO PN# 213-2816
1996- 2002 1.9 VIN 7: AC DELCO PN# 213-970
2000- 2005 2.2 VIN F: AC DELCO PN# 213-970
Crank Sensors for “Compatible 4cyl Engines”
1987-1989 2.0 VIN 1: AC DELCO PN# 213-148
1987- 1992 2.5 VIN R/U: AC DELCO PN# 213-154
1990-1991 2.2 VIN G: AC DELCO PN# 213-148
1991- 1994 1.9 VIN 9: AC DELCO PN# 213-2816
1995- 1995 1.9 VIN 8: AC DELCO PN# 213-2816
1991- 1995 1.9 VIN 7: AC DELCO PN# 213-2816
1992-1993 2.2 VIN 4: AC DELCO PN# 213-148
1994-1995 2.2 VIN 4: AC DELCO PN# 213-148
OTHER HARNESS CONNECTORS
Crank Sensor Harness
AC DELCO PN# 10486180 is a SHORT shielded Crankshaft Position Sensor (CKP) harness that includes the 3 way harness connector (at the DIS Module) and the 2 way connector at the CKP. It may be too short for many applications, but could certainly be lengthened providing you maintain the shielding by using shielded twisted pair audio wire.
Navigate to this AC DELCO Web-Site http://www.acdelco.com/html/catalog/index.htm
and Click on “Display Part Number Image By AC Delco Part Number”
ENTER the Part Number to see a picture of the applicable part (If Available)
Credit goes to WopOnTour
for this information from http://msefi.com/viewtopic.php?t=7142&postdays=0&postorder=asc&highlight=dis&start=36