Setting base/idle timing with Megasquirt? - Third Generation F-Body Message Boards

spills · 07-31-2008, 11:16 AM

I have my suspicons that my distributor MIGHT be 180 out, Ill check that this weekend. But besides that, Im trying to get my HSR to fireoff with MSII standalone (no factory harness), and for now I hav eno O2 (WB or NB), I just wanted to get it fired off just to check my valves and my timing. Im trying to figure out how to get the MS to NOT control the timing so I can set the base timing (from the datalog, it's advancing it 15 degrees while cranking). It will fire off somewhat, but will not run on its own power. When we were rotating the distributor, it sounded like it was trying to fire the motor in reverse. I cannot get to msefi.com from work, so I thought Id post this up on here to see if any of yall fellow Squirters have any advice for me

I think I still have a rough diagram of how I have my ignition setup, Ill have to find it on here.

EDIT: Dont have the diagram here. Basically Im using a small cap dizzy from a 92 TPI just so I can use the hall sensor. So I have switched 12v and ground to the dizzy, and then I have the signal wire going on the 4-pin harness on the dizzy to either pin24 or 36 (cant remember), signal goes into the MS and sends it to the MSD box on the white points wire. I dosconnected this wire becasue from what I read, this would not let the MSD or MS control the timing. But upon doing so, and little more thinking, that would mean there would be NO timing signal to even fire off a spark! So Im just all sorts of lost at this point.

Toehead · 07-31-2008, 11:20 AM

Hello.

Either set every number in the MS table to zero and the trigger offset to zero,

or remove the five volt signal from the override pin to the module.

edit- How do you have the 5 volt override configured on the module? I have a quick disconnect on mine to set base timing.... Speaking of which, I need to retard my base timing a little.... I'ts compensated for in the trigger offset, but my starter hates me

spills · 07-31-2008, 11:32 AM

Im not wuite sure what you mean the 5v override signal. Maybe I just have mine wired incorrectly. You mean module as in the HEI hall sensor, or the MS?

If you can get to the msefi.com forums, I posted up in there my diagram on how I have everything wired up. It's blocked from my work, but it might help better explain where Im at. Ill post it up later on tonight when I get home

Toehead · 07-31-2008, 11:58 AM

Well, the stock ignition control module needs a 5 volt signal for it to accept timing input from the computer. If it does not see the 5 volts, it stays at base timing.

Removing the 5 volts is what you are doing when you disconnect the brown wire when timing a stock setup... Same deal on the megasquirt, but your wiring may be different depending on how you have it set up. I'll go take a look at the msefi forums.

Edit- Couldnt find your diagram but it look slike you are directly controlling a MSD box and just using the module as a hall sensor... Is that what you are doing?

spills · 07-31-2008, 03:49 PM

correct, the only part of the HEI module I am using is the hall sensor, it's not controlling the timing at all. Thats all taken care of with the MS and 6A

Toehead · 07-31-2008, 03:58 PM

I have no experience with that, but I think your best bet woul dbe to make a table of zero's for advance (export yours so you can reimport it) and put the trigger offset as zero.... That should stop you from advancing the timing at all.

spills · 07-31-2008, 04:24 PM

Ill give that a shot and see what happens. Thanks for the help toe!

spills · 07-31-2008, 07:01 PM

found the pic.

Only thing I did different was I ran the HEI power off of the MS power instead of the coil.

Ollie8974 · 08-30-2008, 12:49 PM

Set the MS ignition to 500 or 600 rpm. This way the cranking ign is controled by the module and MS does not start controling Ign. untill the engine is running.

Toehead · 08-30-2008, 01:47 PM

I usually do 300 RPM. 600 or 500 is pretty high.

The megasquirt pulses the injectors every ignition event during cranking. if you set it that high and accidentally get the engine below the cranking threshold, instant stall and flood.