I have a megasquirt 2.2 fully wired up running a 7 pin HEI ignition with six 24# high impedance mopar injectors. I have a required fuel number of 17.3. I have used some of the fuel maps posted in other threads as well as some other sources to get a basic fuel map set up.
I currently cannot get it to try to fire while cranking. can anyone tell me what reasonable starting settings might be for my cranking fuel pulse width? If you can tell me what yours are and how big of injectors you are running i could get an idea of where to start. My current setting is at 3ms and I don't think it is enough but I don't want to flood my cylinder walls with fuel on a brand new motor. Any help would be wonderful, Thank you.

I assume you have checked that the injectors are firing and you can smell fuel out of the TB/intake? Fuel pressure reading? Spark to plugs on cranking? Check timing while cranking or triple check static timing w/motor at TDC?

3 ms sounds too low for cold startup. I can't imagine you will hurt the cyl walls on one fire up if there is some excess gas there.

I'll have to get on my other computer to check my settings. I ran that same setup on my 68 Dart for 8 yrs (24# multi point, V2.2), although w/o HEI, just a regular dist w/advance.

Lou

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Home of Slant6-powered fun machines since 1988

That would be great if you could find your old settings. I do have spark but im not sure of the timing. I have checked it with my timing light but my light fires inconsistently so I am not certain that it is truly at 10 BTDC. (is 10 a good setting for cranking?) I can smell some fuel but just barely if I open up the throttle plates to sniff.

Using the default settings you should be able to get it running, even if its a little rough. The only adjusting you need would be the required fuel and maybe the cold startup enrichment. I suspect there are other issues besides cranking pulsewidth.

Are the PWM characteristics set for high impedance injectors? Even though you're running 3 in parallel (they are in parallel, not series, right?) they still function as high impedance, not one low impedance.

What is the ignition setup... you said HEI, but are you using a pickup wheel & sensor, or the distributor direct to MS, or distributor direct to HEI...? What is the RPM megasquirt is seeing while cranking?

Was the efi running on your first motor, or is this the first time squirting? What is the history of the unit you have?

im using a lean burn non advance distributor running the HEI ignition. this is my first time setting up fuel injection. the MS is from a friends saturn that was running when we upgraded him to a ms2 3.0 board. I have rewired the ignition circuit internally according to the instructions on the diyautotune site for "vintage mopars". The last time this motor ran was on points (someone had spidered in) and a carb. then the dipstick broke off in the pan I spun a rod bearing and the motor went down for a rebuild.

I would consider dropping the point dist in there to get it running, then go back to the MS/HEI after some initial EFI tuning.

Lou

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Home of Slant6-powered fun machines since 1988

Does the megasquirt read any rpm while cranking, and is it steady?

It does read a fairly steady rpm it fluctuates a little but seems to do so with the motor. I have discovered the distributor is 180 out so I am fixing that now and will see what to do from there. btw I currently have my priming pulse set to after 2 seconds. since i don't have to wait for a full rotation to fire like an edis system does should I change that to one of the other settings? I'm not sure exactly what that setting does.

My injectors are 51 lb, required fuel 7.9, 7.9 ms off the basic setup engine constants page, I believe your required fuel should match your ms mine set itself when I did the calculated required fuel page, I have a megasquirt 3.57 board. The priming pulse from what I read purges any air that may have gotten into system from sitting 2.0 at 160 degrees is my setting. For starting you may have to adjust cranking pulse width mine is 301 at 30 degees F, not sure if 2.2 board uses same settings. I do believe your ms setting is way to low at 3 ms if I change my injector size to 24 it calculates 16.8 fuel required 16.80 ms

Today I was trying to get the car going again and was watching my rpm very closely and noticed that it is occasionally unsteady and was even reading zero part of the time while i was cranking. Also my led for spark A turns on and off about once a second while cranking. i thought it was supposed to stay off while cranking so the 7 pin hei would just fire at its static timing. When my megasquirt is off the spark is consistent but I don't think it is when the megasquirt is running. Also my spark B led seems to just be constantly on, which doesn't seem right either. Any ideas?

Actually, the spark B LED being on means that it's not controlling timing (normal during cranking), and when it turns off, the MS has taken control over the timing.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

That makes more sense now. I added a relay to interrupt that signal when the starter is running. when I first hit the starter I get some kind of burst of noise that the megasquirt reads as really high rpm and it seemed to be shutting off the starting disable. I also reran the three wires from the module as individual shielded wires instead of a three wire bundle in a shielded cable. I should have known not to do it that way but I wasn't thinking about cross talk just externally induced noise.

The duster is up and running. The PWM settings had been set for low impedance injectors and my incorrect shielding scheme was causing issues as well. I did end up needing to keep the relay to interrupt the timing enable pin on the 7 pin HEI module. Also I think next time I do this i will get it running on fuel only and then add spark control, it should help with the troubleshooting. Now a little bit of tuning (maybe a lot) I should be able to let you all know how the ford diaphragm pressure plate works out.
Jerame

Welcome. I got bit by that low impedance setting before that's why I said to check it

Interrupt relay... did you wire the HEI module per this ? Still takes a relay, but it shows how to use it to take advantage of the HEI module built in override mode.

I tried to but I couldn't find a good circuit that was hot in run and not in start. I didn't want to use anything that wasn't under the hood for my wiring options since my under dash wiring is such a mess from the previous owner.
I used a 5 pin relay with an 87a pin that is connected when the relay is not activated. Then I was able to use the starter relay signal wire to activate the relay and interrupt the timing enable signal.