Sequential fueling but using wast spark ?

[B85]

Going to use MS3x for a 3800SC build and need to know if sequential fueling will work with batch ignition ?
Here is a photo of the coils it has.

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[URL=http://s916.photobucket.com/user/s ... .jpg[/img][/url]



Ideas ?
Randy

[jsmcortina]

In order to have sequential fuel, you need suitable crank and cam signals. So long as you have those, yes you can run sequential fuel and wasted spark.

James

[B85]

Thanks James.
The cam signal comes from a single point on the cam driven gear and the crank has a 18 count signal . But the info from the GM manual said the ratio of 18x reference pulses to 3x reference pulses received by the PCM does not equal 6 to 1 .Then it said, the ratio of 3x reference pulses to CAM signal pulses received by the PCM equals 6 to 1.

My way of thinking is the cam driven gear will signal once for every two turns of the crank shaft . So its like 9 to 1 ?

This is all new to me.
Ideas ?

[dontz125]

Different ECUs, different ways of doing things. What you've described is a dual wheel arrangement, 18-0/1. So long as that cam trigger edge never coincides with - or worse, passes - any crank trigger edges, the MS will be just fine.

[B85]

Good. Not quite to the point of wiring but wanted to get some ideas of what GM was doing.

Also have a "Boost Bypass Valve with a boost bypass switch controlled by the OEM system. Looks to return compressed blower air to the intake track. (loop) ?
Have not found when the OEM opened it or closed it ? Still reading. Think one of the analog switches could run it but not sure ? Switch sends a vacuum signal to a diaphragm to open and close the port in the blower body.

Also,I could build a coil for all cylinders to take advantage of the MS3x but will it help ?

Thanks much for the input !
Randy

[jsmcortina]

I believe that other customers have kept the C3I or GMDIS module and sent the 3X and 1X signals to the Megasquirt. You'd set it to "Dual Wheel" and three teeth at crank speed.

There is some GMDIS information in the hardware manual.

James

[B85]

Thanks James, I will head to the manual and have a look see.

I found in the GM manual that the crank pulley has 2 interrupter's one with 3 slots and one with 18 slots ( Hall-effect ). It is used with a dual crankshaft position sensor. The inner one has unevenly spaced blades. From what the manual said its to fire the right coil in this system. (its from 1998 ) Called a CKP Sync. pulse.

Off to the
Randy

[B85]

James, this is a non-distributor motor. You know but I did not want to get something wrong. ( reading in the manual for the MS3x )

Looks like + Nonmissing tooth on crank and Single tooth on cam .
Now I get the 18-0/1. Sorry !

[Space387]

You appear to have the same set up as my gm 3.4l I left the 3x signal going to the icm, and ran the high res and the single pulse to MS3. It works perfectly.

[B85]

Hi,387.

First let me say " I'm new at this ! " So,if the 3x is running the ICM can the MS3x play with the timing ? Or is it just controlling the fuel ?
Randy

[B85]

Here is my starting list. Did I miss anything ?

1 x MS3 Realtime Clock Module
1 x JimStimX Expansion Board - Unassembled
1 x MegaSquirt-III EMS System with MS3X Expansion V3.57 - Assembled
1 x MS3 Knock Module Kit
1 x 10' MegaSquirt Wiring Harness for MS3X
1 x 10' MegaSquirt Wiring Harness (MS1 / MS2 / MS3 Ready)
1 x GM Open Element IAT Sensor with Pigtail
1 x USB cable for MegaSquirt-III
1 x Innovate LC-2 Digital Wideband Controller with Sensor - 3877

Randy

[racingmini_mtl]

You also need the JimStim. The JimStimX you listed is an add-on for the base JimStim.

Jean

[B85]

Thanks Jean. I should have said I all ready built that to make sure I could.

[B85]

Have the JimStim up and running. All LED's tested.

Can I set the JimStim to simulate the 8-0/1. And if so , How ? (very new at this)

Thanks,Randy

[racingmini_mtl]

This is where all the JimStim wheel modes are shown: http://www.jbperf.com/JimStim/JimStim_v ... .html#mode. Set the DIP switches for the 8/1 mode.

Jean

[B85]

Thanks Jean.
Its a little hard to read between the lines .Was hoping to see how you come up with the 8-0/1 from the trigger wheels. With it being a 18 tooth wheel . Where did the 8 come from ? It would make more sense to me if it was 18-1? That is coming from a 18-0/1 set of wheels. I guess I'm looking for a how to convert manual ? I know I don't need it but would like to be able to get my (small) mind around it.
Randy

[racingmini_mtl]

Randy,

You asked for a way to simulate 8-0/1. I gave you the way to set this on the JimStim where it is called 8/1. I have no idea what actual setup you have but if you do have an 18/1 then you won't be able to simulate that with the JimStim. The patterns available are shown at link I gave above.

Having said that, if your pattern is not available, you can still do some bench testing but you'll have to use a different pattern. Then once you know everything works as it should, you'll switch your MS settings to the correct pattern when you install the MS on your car.

Jean

[B85]

This my be "Dumb" but here is my JimStim. Have not done any board building for some time. Fun ! And I didn't burn myself .



In reading other post's about overheating the LED's. I put a wetted paper towel ( heat sink ) against the LED's under the board when soldering them. May or may not be a good idea ? but they all work .
Randy