dyno results

[Alxsmt]

the maps are a little different.. I did not check that acually lol. I was told by another ms guy that everything is correct as far as timing goes when you hook it up with our ignition

[carbon]

the maps are a little different.. I did not check that acually lol. I was told by another ms guy that everything is correct as far as timing goes when you hook it up with our ignition

Another MS guy with a Gen III 60* or just another guy with a MS controller?

[Alxsmt]

yes a guy from v6z24, ms2 and now ms3. But I did get my startup tune from him, with a setting wrong... DIYAutotune figured that out for me.

[carbon]

I am going to be running my 3500/F23 swap with MS2... good to see you're making progress. Helps me as well.

[Alxsmt]

hey what did you guys do for pin C7? "bypass" mine has nothing going to it. a freind of mine is doing ms on his quad4 so he was comparing my pins with his. basically the same.. he noticed that c7 needs 5v.. I hooked up 5v to it and it didnt seem to make a difference. gonna wire in a toggle switch tomorrow to see if I can notice anything. getting more tunning done this weekend so im trying to figure this out before then.

Im waiting on a reply from DIY


an email he FWD to me:
"Here is how the Bypass works on a stock ECU system... you put your key to start, and the Bypass pin on the ICM is dead, or zero volts. This means it is NOT in Bypass mode....which is another way of saying the ICM is in complete control of the ignition timing. During the time you are cranking, the ICM looks at the crank sensor and comes up with a 10* of advance which is automatically applies to the spark plugs/engine during cranking. It does this even without taking any instructions from the ECU... you dont even need an ECU plugged into your car and the ignition will fire sparks at 10* during cranking. Once the engine RPMs are sensed to be above 300 RPMs by the ECU, it desides the engine must be running now, so it applies 5vdc to the Bypass pin to "BYPASS" the ICM and take over control from it. Basically the ECU is saying, "Hey, ICM, you take orders from me now!" Once the Bypass is hot, then the ICM begins to look for ignition advance instructions from the ECU to come in on its EST line. The EST means Electronic Spark Timing. This is signal is a pulse train that contains information about what the spark advance must be and the ICM will follow the directions given to it.

So, when you switch to Megasquirt, something needs to provide this Bypass feature to get the engine started. It can be a relay if you want. But it must switch 5vdc and not 12vdc. Or you can just use one of the MS outputs and set it up to behave as a "bypass" signal. Either way is cool, and I dont think one is better than the other. I would personally do it inside of the Megasquirt becuase i hate adding external relays... but if thats what you wanna do, it will work just fine that way.

You will have to hook up the EST line to the Spark A output of the Megasquirt. And then configure the Megasquirt to run GM HEI DIS mode. This will make it create the needed EST signal that your ICM is expecting to see."


IF this is true for my case, how am I able to change the timing and notice a difference?

[robertisaar]

the above information is correct. without 5V applied to the bypass circuit, the ICM is NOT supposed to use the EST signal from the ECM.

another interesting tidbit would be that the EST signal also controls dwell when the bypass circuit has voltage on it as well, when it doesn't, the ICM controls it.

[Alxsmt]

that means I have to pay $200 more for tunning.. I think..

wouldnt that mean any timing changes in the computer would have no affect?

[carbon]

That should have been part of the set up instructions for HEI/DIS in the Mega-manual...

To use the GM DIS module, build your MegaSquirt® as shown in the GM HEI section. To connect the module to MegaSquirt:

Module pin B or C - white wire - DB37 #36 (V3 main board, ignition output signal pin for V2.2),
Module pin A - tan/black wire - Connect to a bypass relay as shown for the HEI modules,
Module pin E - purple/white wire - DB37 pin #24 (tach),
Module pin F - red/black wire - ground,
Module separate connector - black/white - ground,
The module also has connections for power (pink), the crank position sensor (yellow & purple), and tach (white).

I am definitely looking forward to all of my own bugs later this year...

[Alxsmt]

I know this is kinda going off topic... but what do you guys have for the trigger angle? and pulses skipped?

at idle its at about 7*, computer shows 17*. reved up it its at about 20*, computer shows 30*. with 5v and without 5v. no change. I have tired playing with trigger angle and pulses skipped with no change. Im also not getting a reading on my timing mark ever 5 seconds or so, it skips a blink.

Im slightly lost lol. I really should have done this from the start..

emailed DIY also. Ill post what they say

[dskopek]

I know this is kinda going off topic... but what do you guys have for the trigger angle? and pulses skipped?

at idle its at about 7*, computer shows 17*. reved up it its at about 20*, computer shows 30*. with 5v and without 5v. no change. I have tired playing with trigger angle and pulses skipped with no change. Im also not getting a reading on my timing mark ever 5 seconds or so, it skips a blink.

Im slightly lost lol. I really should have done this from the start..

emailed DIY also. Ill post what they say

From what I am reading you are showing 10 degrees less timing on the motor then what MS says? If that is true you can dial that right in with the trigger angle settings, Just put a timing light on the motor and adjust the trigger angle until the computer and timing light match. I am running a Ford EDIS system on mine and had to tweek mine to get it perfect and have had no problem since.

[Alxsmt]

yes thats what I was thinking. the trigger angle has no affect on it..

today I got ahold of my friend old snap on timing light to verify. same readings. I also set ms to fixed timing, 0-20* had no affect on the timing with or without the 5v. I did check to make sure it was making it to the ICM.

is this making any sense at all?? its not making any to me!!

[Alxsmt]

alright. made some progress. DIY is clueless as to why I dont have spark control, they want to see the oscilloscope readings.. factory computer controls it correctly.. SO I ordered a scope..

In the mean time, I had more tuning done on the fuel side. about few hours on the dyno and an hour on the road. OMFG the car drives amazing! its unreal. basically zero issues. my idle issue was the throttle plate adjustment wasnt open enough, we opened that up a little and he did a little tunning.

I attached a pic of my fuel table

[robert 1980]

Nice i agree drivability is the shit.I remember way back when all the random issues i had running OBD1.Cool glad you have everything fixed=)

[Alxsmt]

thanks, still have the spark issue tho lol. Maybe someone else can learn something from my issues/fixes

[pocket-rocket]

Did you assemble your MS or was it a preassembled unit? I would love to assemble one. I'm one of those weirdos that find soldering stuff like that together fun, lol.