MegaSquirt For Dummies......

[dieselgeek]

For reference of the steps I took.

Megasquirt 1 on the Thunderbird with TBI (had HORRIBLE electrical noise I eventually nailed down to a broken solder joint in the Alternator, runs good now).

MegaSquirt 2 on the Skylark with B&G code. Multiport fuel only, alternating firing (to this day), and 4-pin IAC idle control (also to this day).
Fuel and spark with a 7-pin HEI
Fuel and spark with the MS plugged right into the HEI pickup coil and MS2 controlling an MSD 6AL box
Fuel and crank trigger (off an escort) and MS2 controlling an MSD 6AL box
Same as above but have ugraded to MS2/extra code.

Future plans are limited to adding LS coil packs, wasted spark style, eliminating the MSD box and distributor. And get the damn knock sensor working. I think I have the wrong size resistor on my pull up circuit. ([hi-jack] I get variable voltage from the knock module, but I need to get some readings from actual driving, then size the resistor accordingly [/hi-jack])

FYI, the only time I've had luck with knock sensors is when I used a "knocksense-MS" - google it, they're still made. You're simply going to need an adjustable conditioning circuit to have any hope whatsoever of meaningful knock control.

[dieselgeek]

Matt, Scott thanks for the replies!!!...... And just to clarify the coil on plug will happen down the road after I get the car running and tuned with the stock setup......I just basically don't want to have to de-solder a bunch of stuff when I decide to go to the coil on plug setup......And Scott I know I can run wasted spark....but for me it's more about the learning curve of running them individually.....

I also have to see if I want to bother running the A/C in this car, which brings up a few more variables since the ECM controls the A/C clutch.......

So I guess I'm at a point where some planning is needed, I'll solder in the IG1 to IGN jumper and that should concluded the jumper part of the assembly......

Also Scott to help you fallow along on what I'm doing, here's the page at DIYPNP that has the setup for my car....

If you scroll down a little you'll see a table with the stuff that I have to do........

http://www.diyautotune.com/diypnp/ap...88-2_3-mt.html

it's a little confusing for me as I have never done the DIY-PNP. But the learning experience seems to be about the same, once youget this one running - it's downhill from there. In a good way.

[TheSilverBuick]

FYI, the only time I've had luck with knock sensors is when I used a "knocksense-MS" - google it, they're still made. You're simply going to need an adjustable conditioning circuit to have any hope whatsoever of meaningful knock control.

I get a reliable 4 to 8 volts out of the GM knock module output depending if the engine is idling, rev'ing, etc. Assuming the resistor is supposed to cut the voltage in half, so I get 2-4 volts, the B&G code had a voltage threshold setting (drop below 3 volts pull timing, etc), but the extra code doesn't seem to have a setting and I haven't found what the threshold value is, and as soon as I turn on the Knock sensor option it pulls full timing even at idle. It may require replacing the resistor in my pullup circuit with a small potentiometer. You can tell it's low priority since I haven't fully troubleshooted it.

[TC]

FYI, the only time I've had luck with knock sensors is when I used a "knocksense-MS" - google it, they're still made. You're simply going to need an adjustable conditioning circuit to have any hope whatsoever of meaningful knock control.

The board that the DIYPNP comes with has the Knock Sensor circuit built into it....Look at the pic, the gray box(just right of center) with the little brass screw in the top of it is the adjustable resistor to tune the knock sensor..........the knock sensor on the Thunderbird only has one wire running to the ecm, so I'm thinking that once I get things up and running I will hook it up......

[TheSilverBuick]

Like GM, there is probably a knock sensor module external from the ECM that conditions the signal.

[dieselgeek]

I get a reliable 4 to 8 volts out of the GM knock module output depending if the engine is idling, rev'ing, etc. Assuming the resistor is supposed to cut the voltage in half, so I get 2-4 volts, the B&G code had a voltage threshold setting (drop below 3 volts pull timing, etc), but the extra code doesn't seem to have a setting and I haven't found what the threshold value is, and as soon as I turn on the Knock sensor option it pulls full timing even at idle. It may require replacing the resistor in my pullup circuit with a small potentiometer. You can tell it's low priority since I haven't fully troubleshooted it.

Maybe your path will lead down a different road, but for me - once it was hooked up and "threshold adjusted" then all I got was knock when there shouldn't be any knock, and no indication when there was audible knock. Frustrating.

[TheSilverBuick]

Won't know until I try

[squirrel]

Maybe your path will lead down a different road, but for me - once it was hooked up and "threshold adjusted" then all I got was knock when there shouldn't be any knock, and no indication when there was audible knock. Frustrating.

you need an inverter...

[TC]

Ok this is just more of a clarification question...

On the jumper table that is on this page http://www.diyautotune.com/diypnp/ap...88-2_3-mt.html it says under "Pullups" this...... "IAC Flyback Diode Banded end to 12V", so in the pic below I outlined the IAC circuit in yellow representing the way the diode is suppose to be mounted....My question is, am I correct about this??

[TC]

Like GM, there is probably a knock sensor module external from the ECM that conditions the signal.

Not on this car, the wiring diagram doesn't show anything between the sensor and the ECM......

[TheSilverBuick]

Hmm, interesting, common ground and a signal wire. I should look at Fords more, I didn't know of two wire knock sensors.

[dieselgeek]

Ok this is just more of a clarification question...

On the jumper table that is on this page http://www.diyautotune.com/diypnp/ap...88-2_3-mt.html it says under "Pullups" this...... "IAC Flyback Diode Banded end to 12V", so in the pic below I outlined the IAC circuit in yellow representing the way the diode is suppose to be mounted....My question is, am I correct about this??

I say "Yes."

[TC]

How important is it to have a Baro Pressure sensor??

[dieselgeek]

How important is it to have a Baro Pressure sensor??

Randal has proven that it's quite handy to have! Does the microsquirt code support it, and have a table that lets YOU make the final adjustments? if so then I say "important." Also you live in a part of the country where short drives can result in large gross elevation changes. I recommend trying to make it work.

Also, be glad that you have a cheap-o megasquirt and not a FAST, BigStuff3, or Gen 7 DFI (the most popular systems) - none of those POSs allow you to adjust the baro curve, they use "default" curves that don't work hardly at all.

[TheSilverBuick]

*Conversely, closed loop O2 corrections should work close enough for most. I almost never run mine in O2 closed loop, so it's particularly important to have a baro table set up then.

But as I also proved, you can drive places that can exceed 15% and 25% changes in air pressure, so unless you let the closed loop system run-amok with 50+% correction ability it could cap out and not correct anymore. But it's really only a problem if you live at the top of the mountain, as going up hill from a base tune only makes it run richer, and why most get away just fine without it. In September my car saw 101kpa Baro pressure AND 64kpa Baro pressure. Quite the range, which isn't common, but the MegaSquirt handled it like a champ and my AFR's stayed where I wanted them, with out the O2 corrections.