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Discussion Starter #1
Hello gents, very confused here...

I'm now planning on building my THIRD megasquirt 2 using the info contained here, or atleast, it WAS contained here:

Chrysler 2.2/2.5 mode on the MegaSquirt

The previous two I built have been in service, with wasted spark, batch fire injection for over 4 years now, using the turbo distributer and dual hep circuit.

I'm trying to build a setup for my brother, but didn't save my old information. Now all of a sudden it is a bad thing to build?

Any insight would be appreciated. I have plenty of transmission destroying videos and pictures to prove this 2.2/2.5 mode works very well!

All the best,
Eric
 

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Apparently it didn't work equally well for everyone. The new 3.3.1 firmware uses just a single HEP signal brought in over the VR conditioner.
 

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I had trouble with it. I know it originally worked and then around the time ms3 was rolled out there were problems with the code. I had to swap the drivers for fuel and spark to get it to run. After I corrected that I still had a problem with cyl 2/3 ignition or timing. I swapped to 36-1 wheel and hall effect swapped fuel and spark drivers back and car ran fine. There was another post it had since been fixed.
 

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Discussion Starter #4
Ok, thanks for the replies Gents,

Hope I didn't com across as an a** asking for information :rolleyes: Just trying to get things setup and was alarmed that this data and information has been deleted.

The main reason for the need for a distributor setup is the megasquirt that i'm now putting in my Jeep Comanche 2.5 CB swap. I really don't want a 36-1 tooth wheel on the front crank pulley, as I can just see disasters with mud, sticks, and water fording causing issues offroad. I had coated an old dakota engine bay with a 2.2 in mud (don't ask haha) and never had electronic issues with the OEM distributor/ignition.

So, can anyone point me in the right direction? Can we still use this mode with the new code now? Can I switch to a single HEP (TBI) distributor instead? I just need to order a 36-1 tooth wheel asap from DIY if that's the only way it will work. but I REALLY don't want to go that route.

Thank you!
 

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Could you run an older code that you know worked for you in the past? The 36-1 wheel I used was custom made to slip over the inner lip of the crank pulley I then chucked it in the lathe and trued it with a dial indicator then welded it up. None of the off the shelf wheels looked like a good fit to me. Good luck.
 

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Discussion Starter #6
Thanks for the info Wallace. I could run the older code, but it would be nice to upgrade for the additional support.

If it's also true with the new code that we can run a Single HEP TBI distributor through the VR circuitry, that would be very handy!

Anyone have any info on this single HEP mode with the V3.3.1?
 

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I used the vr circuit for the hall effect sensor on the crank trigger...very nice clean output so should work just fine with the tbi hep.
 

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I think I heard one of the problems was "perceived" long cranking time?

Maybe I'm remembering that wrong??
 

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Discussion Starter #9

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Hello gents, very confused here...

I'm now planning on building my THIRD megasquirt 2 using the info contained here, or atleast, it WAS contained here:

Chrysler 2.2/2.5 mode on the MegaSquirt

The previous two I built have been in service, with wasted spark, batch fire injection for over 4 years now, using the turbo distributer and dual hep circuit.

I'm trying to build a setup for my brother, but didn't save my old information. Now all of a sudden it is a bad thing to build?

Any insight would be appreciated. I have plenty of transmission destroying videos and pictures to prove this 2.2/2.5 mode works very well!

All the best,
Eric
What firmware version were you using that worked well? I want to reference it and try and fix the code...
 

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I have decoded the stock wheel in my custom atmega128 based ECU. Perhaps my method can help. The window is detected on #2, so is ready for #1 event.

I use a timer to measure rising and falling edges, the tab metal gives a sensor high, window a low. The width of the tabs and windows are measured in timer ticks, if the current window is less than 1/2 the prior window width, it is the sync tab. The tab width of the sync tab skips the window.

The tab information is used for timing reference. And is subdivided by the electronic advance functions. The sync information is used for direct fire neon coil drive, and 2 bank injector delivery.

My code is in C, for ATMEL AVR. Not sure what ms, uses.
 

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I have decoded the stock wheel in my custom atmega128 based ECU. Perhaps my method can help. The window is detected on #2, so is ready for #1 event.

I use a timer to measure rising and falling edges, the tab metal gives a sensor high, window a low. The width of the tabs and windows are measured in timer ticks, if the current window is less than 1/2 the prior window width, it is the sync tab. The tab width of the sync tab skips the window.

The tab information is used for timing reference. And is subdivided by the electronic advance functions. The sync information is used for direct fire neon coil drive, and 2 bank injector delivery.

My code is in C, for ATMEL AVR. Not sure what ms, uses.
This is why I don't attempt to run anything other than stock or modded by someone else LOL! Looks easier to learn Klingon!
 

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I agree with you, but working with micro's is easier than English, or me developing people skills.

Here are my code stubs in CVAVR C:

// External Interrupt 0 service routine
// Falling edge of HEP signal, happens end of tab, and at end of window in sync tab
// cylinder index
interrupt [EXT_INT0] void ext_int0_isr(void)
{
static unsigned int TabLenOld = 7580; // initial pre start cranking estimated value at 200 rpm
MopWinSt = TCNT1; // capture start of Window end of Tab
TabLen = MopWinSt - MopTabSt; // measure of tab length
if (TabLen < (TabLenOld>>1))
{
SyncDet = 1; // sync discovered
}
if (SyncDet == 3) // index when in sync
{
if (++SpkIndx > 4){SpkIndx = 1; SyncDet = 0;}; // sets cylinder spark index
TabLenOld = TabLen;
};
if (SyncDet == 2) { SpkIndx = 1; SyncDet = 3;};;
}

// Timer1 input capture interrupt service routine
// Rising edge of HEP signal
interrupt [TIM1_CAPT] void timer1_capt_isr(void)
{
if ((SyncDet == 0) || (SyncDet == 3))
{
MopTabSt = ICR1; // capture start of tab, also end of window
WinLen = MopTabSt - MopWinSt;
CalcI = TRUE; // Ignition calcs
}
else if (SyncDet == 1) SyncDet = 2;;
}
 

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