Buick 3800 C3I DIS and MSnS-E Setup Info

[WopOnTour]

I have been doing some extensive testing on the Buick 3800 Computer Controlled Coil Ignition (C3I) system for MSnS-E (Fidle as spark control) using my MS and a 2000 C3I mockup that I have. The scope waveforms and patterns look very promising.Here’s what I have learned so far (although keep in mind this was done in a mock-up state only and NOT on a running engine) If anyone out there that wants to MsSquirt a Buick 3800 and needs additional assistance or support (ie schematics -etc) please feel free to PM or email me

In order to potentially run the C3I ignition as used by the 3800 with MSnS-E you will need to REROUTE the following signals from the C3I module to the MS:

- connect the purple/white wire (C3I ignition module terminal D) to PIN24 of the DB37@Megasquirt. This C3I signal is commonly labeled “low resolution engine speed signal” is actually a digital 3X (ie transitioning every 120 degrees of crankshaft and) near identical to the old DIST REF but is “synthesized” by the C3I module from the 18X hall-effect input (18/6=3)
*NOTE-This circuit was previously routed to the oe ECM.

- connect the “IC Timing signal” (aka 5V Bypass) which is the Tan/Black wire at terminal B of the C3I ignition module to pin 27@DB37 of Megasquirt. James has now configured this to go to 5V when RPM>400 as discussed here: http://www.msefi.com/viewtopic.php?p=41 ... ght=#41529
*NOTE-This circuit was previously routed to the oe ECM.

- Finally the Electronic Spark Timing (IC timing control) a white wire at pin A of the C3I ignition module to the reconfigured LED17 @ Pin25 at the Megasquirt DB37 connector.
*NOTE-This circuit was previously routed to the oe ECM.

* These mods assume you have:
-D8 jumpered (shorted) or removed and bridged
-XG1 jumpered to XG2
-Fidle/LED17 and LED19 reconfigured as outputs as shown here:
http://megasquirt.sourceforge.net/extra/setup-hei7.html

What I did was trim a 1000 ohm resistor on one end and with a small needle nose, make a small J-hook on the lead to hook under the RH end of R23 and R27 (as viewed with the DB9 serial connector on left) and soldered them (vertically) there. You might as well do R26/LED18 while you are at it a.

Then I bent the other resistor lead into a "reverse-S" shape so as to connect to the cathode(-) side of the case LEDs ("top" LED leads as viewed with serial port on left) and soldered them there.

Then add 2 small "hookup" wires to connect to these outputs circuits to X11 and X12 (as well as the "extra" output #4 from LED18 to X13)

Then wire:
X11=DB37 pin 25 to your EST (timing control) circuit PIN A of your C3I module

X12=DB37 pin 27 BYPASS to PIN B of your C3I module

DB37 pin 24 of the MS to PIN D of the C3I module (IGN REF)

*You MAY want to make sure there is identical ground potential between the MS and the C3I module by connecting Pin L of the C3I module to the same engine ground point as your Megasquirt.

Here's a link to some pics showing the internal wiring mods in one of my Megasquirts
http://www.msefi.com/viewtopic.php?p=43 ... ght=#43557

MOST of the remaining connections at the C3I ignition module MUST REMAIN connected as factory. These include IGN+ (terminal P), Ground (terminal K) and the circuits to the various hall-effect sensors (terminals G,H,J,M and N) While all of these sensors are not necessary they do share a certain amount of circuitry (see schematic) and will facilitate future possible use of these signals (for possible enhancement through wheel decoding or maybe SFI on the MSII)

The following circuits at the C3I ignition module that can be safely removed as they went to the OE ECM. (actually it’s recommended that these circuits just be either “clipped” at the ignition module to maintain connector seal integrity or just insure they are properluy "dead-ended") So you can safely "clip the wires to IGN MODULE terminals
C (Medium Resolution Engine Speed Signal)
F (Camshaft Position Signal) and
L (low reference)
*The wire at E can also be clipped as AFAIK was never used anywhere.

This should work for any Buick 3800 from 1988 to present

NOTE: Depending on the C3I module used you MAY have to bypass the Opto coupler within the MS directly connecting the IGN REF input at pin 24 to the opto output as outlined by James' in the following thread: http://www.msefi.com/viewtopic.php?t=7034
*NOW ON TO GM-Direct Ignition Sytem - Stay Tuned

Regards
WopOnTour

[Boosted2003]

Yeah, I would like to use my stock 2002 ignition setup instead of using ford edis.

[houlster]

What I did was trim a 1000 ohm resistor on one end and with a small needle nose, make a small J-hook on the lead to hook under the RH end of R25 and R27 (as viewed with the DB9 serial connector on left) and soldered them (vertically) there. You might as well do R26/LED18 while you are at it a.

I'm still un-clear where you're wiring the resistors into. You say it goes to the end of R25 and R27 for the two different LEDs.

The HEI page referenced (http://megasquirt.sourceforge.net/extra/setup-hei7.html) says R25 and R23.

Looking at the circuit diagrams on that page, it appears you wire the 1k resistors to R23, R24 and R27 for the LED17, LED18 and LED19 diodes, respectively. Correct?

Are there any pics of these mods? I've been looking, but haven't found any yet.

--Dan

[WopOnTour]

Yes, sorry that was my bad- it should be R23 and R27 (got my wires crossed with the DB37 terminals)

I have changed the original post as well
THANKS for pointing that out, hopefully now it will make more sense
I posted a picture somewhere showing how I added the resistors, but in a perfect world you could add the 1k resistors much easier while you are building the MS by twist-soldering it across one side of the resistor and to the anode of the LED, prior to soldering them to the circuit board.

Below is a picture of this modification on one of my boards
As you can see I ended up oversoldering them a bit as all I had available at the time was 1.5 mm dia, which was way too large, I since only use .8mm for these mods. It's not pretty but it'll do

Regards
WopOnTour

[houlster]

- connect the purple/white wire (C3I ignition module terminal D) to PIN24 of the DB37@Megasquirt.

Nother question. This is the "Tach" pin that in MS was recommended to be a shielded wire. Do you think this is needed here? The purple/white C3I wire isn't shielded, so should I bother shielding the wire from my relay board to the MS?

--Dan

[WopOnTour]

- connect the purple/white wire (C3I ignition module terminal D) to PIN24 of the DB37@Megasquirt.

Nother question. This is the "Tach" pin that in MS was recommended to be a shielded wire. Do you think this is needed here? The purple/white C3I wire isn't shielded, so should I bother shielding the wire from my relay board to the MS?

--Dan

Not really neccessary, but you can if you want (or if your application has the IGN REF running close to alternator , secondary wiring etc.) If you DO, just make sure the shielding is grounded at the MS end only.
Regards
WopOnTour

[houlster]

I will post more details later when I get a chance, but I've got my L67 up and running fuel and spark using WOP's instructions here.

I still need to work on the timing and fuel maps, but I'm running a bit rich and not a lot of advance until I get my intercooler and WI plumbed. But, so far so good. Awesome work WopOnTour!! I couldn't have gotten it going without your work. I'll still be picking your brain in the next couple weeks too ta get this thing dialed in...

--Dan

[WopOnTour]

That's great news Dan!
Sounds like you are about where I got- Bypass only
I would just keep playing with the TRIGGER ANGLE and TRIGGER ANGLE ADDITION values until Megatune and your timing light align.
If you get those numbers hammered out- please post them here.

I should have my 3800 C3I mockup back next week, so I might be able to help get you values that work.

CONGRATS THOUGH IFAIK YOU ARE THE FIRST MSer TO GET C3I FUNCTIONING ON A RUNNING ENGINE GREAT JOB!!
Regards
WopOnTour

[houlster]

Ok, I got it running, left the next day for a 500 mile trip, wheeled for a week, and just returned yesterday. How's that for faith in MS? (I did loose the water pump pulley though...)

Little more info: I have an '01 Series II 3800 SC motor out of a Grand Prix GTP. I've adapted it to RWD in my truck using a custom intercooler/adapter/water injection plate and an Eaton M112 SC off a Ford Lightning. See my (lenghty) swap post here. I'm using MSnS-E code on a v2.2 board, with a v1.0 board as backup.

The board mods done are as WopOnTour specified here.
LED17 / X11 is used as Spark Output (IC timing control)
LED19 / X12 is used as Spark Output B (Bypass)

I also upgraded the transistor on Fidle (detailed here) so as to PWM the Ford IAC valve that's part of the Lightning's M112 intake.

These same mods can be done to a v1.0 board, but I ran the hookup wires on the underside of the board to connect directly to the DB37 connector pins (since there are no X11,X12, etc ports in the board).


Using MTune, I set the dialogs:
Code Config -> Codebase and output functions
Spark -> Dwell settings
Spark -> Spark settings

Dialog pics attached:

For the Trigger Angle, I started with 60 deg as Wop suggested to me, then I put a timing light on the crank pulley with the bypass disconnected (base timing set by the ignition module at 10 deg). Watching a mark on the pulley, I could see it jump when I connected the bypass wire (base timing set by MS). I adjusted the Trigger Angle untill the mark no longer jumped when I connected/disconnected the bypass wire. That turned out to be 70 degrees.


I still have to work out a good timing map (<cough>, <cough> Wop <cough>,<cough>), but MS is controlling the C3I ignition timing now and I've got about 1100 miles on it so far...

--Dan

[Boosted2003]

Im assuming since you said " ign+ " you are referring to the 12 volt switched power source.

[CPOM]

edit: see below

[CPOM]

V3 Board Mods

WopOnTour's Instructions say:

* These mods assume you have:
-D8 jumpered (shorted) or removed and bridged
-XG1 jumpered to XG2
-Fidle/LED17 and LED19 reconfigured as outputs as shown here:
http://megasquirt.sourceforge.net/extra/setup-hei7.html

-D8 (the "John" Zener) on the V2.2 board is D2 on the V3 Board.
-XG1 and XG2 are the same on the V3 Board
-LED 17 and LED 19 are D14 and D16 on the V3 Board, R24 and R28 are the corresponding resistors he is referring to:

Add 1k resistor from (-) of D14 to the right (5v) side of R24
Run a length of wire from D14(-) to IAC1A
Add 1k resistor from (-) of D16 to the right (5v) side of R28
Run a length of wire from D16(-) to IAC1B

Hope this works, I'll post up what happens!