My experiences with Megasquirt

[krazydriver]

zig,

i was just wondering how you'd wired up the power to the megasquirt. I was planning on taking the switched power from the factory EFI relay, then running that into a fusebox then from there distribute power to everything as seen in this picture. i was planning on just running the thermo fast idle for now. just so i won't have to interface anything else with the megasquirt.

Did you have to add any relays to get everything to work? or should i be good doing it this way?

[krazydriver]

never mind, was looking at some stuff from DIYautotune and realized i do need another relay to properly ground with the ignition on.....

On a side note though one of the diagrams in the FSM shows that an air regulator gets power when the fuel pump is on. I'm not positive but it looks to be the IACV air regulator. So maybe i won't need to run power and ground to it?

[ZiG]

Right, the iacv gets pwr separately. It's just one pin on the stock ecu that wou'll need to run to the MS, and then add the diode in.

I modded the ecu relay and the power to the injectors as shown in that diagram, and the MS itself still gets power from the 2 wires that power the stock ECU.

[krazydriver]

cool,i'd really meant to get started on the bulk of the wiring today but i got caught up in other things. I did manage to put my wideband in so hopefully monday i'll be able to finish up most of the megasquirt stuff.

[krazydriver]

Power and grounds are done. Injectors and coil are set. Now i just gotta finish up the sensor wiring and everything will be good.

I'm going to take a bunch of pics of how i wired everything, so expect updates with pics tomorrow/wednesday.

[ZiG]

Cool.

Using stock coil or what?

('cause if you are, you'll have to bypass the power transistor if you havent already. And even then, might be iffy.)

[krazydriver]

zig, i've got an msd blaster SS. so i should be good.

alright here's how i wired the megasquirt power and grounds. I ran a completely separate relay as shown below. I'd like to leave as much of the factory wiring as possible, at least until megasquirt proves it can make my car run. At that stage i'll be revising the below drawing because i'll be powering the fast idle thermo switch and (if i don't remove them) the solenoid for the butterflies.right click and view image to clear it upMegasquirt and the LC-1 share a ground point. I'll probably leave the rest of the sensors on the factory ground lines, and i'll get up some actual pics of the wiring madness tomorrow.

For sensor wiring just follow the megasquirt external wiring diagram i posted further up.

To remove the constant 12v to the injectorsTo cut the constant 12 volts to the injectors just go down right next to the battery and the washer fluid filler. You'll see a grey connector. Unplug it and from the cold side(if your worried you can just unplug the battery) i just removed the connector for the red wire.

I'm going to be using the thermo switch fast idle which only needs 12v and a ground to work. Currently it will be receiving both of these through the factory harness... so it should be fine.

If i can get some cover over my car, or if it doesn't rain tomorrow. I think i'll be able to do all the sensor wiring. Most of which will just be extending the factory ecu sensor wires so that they'll reach to where megasquirt is mounted. if the wiring goes well maybe i'll post up a first startup (or failed startup) vid.

[ZiG]

Cool. I couldn't be sure of that connector you speak of (to remove power tot he injectors) so I opted to cut the wires right where they went from the harness on the firewall, to the one over the fuel rail. And I got power from the stock ecu wires. I had some problems with grounding though, had to ground it straight to the battery, or else it would have reset issues.

I look forward to seeing the end result!

[krazydriver]

WE HAVE IGNITION!!!!!!!Finished wiring everything but the IAT (I'm still NA, so tomorrow i'm going to have to pull the intake tube off and find someway to mount the temp sensor in it...)

I'd been testing while i wired so i knew power worked, i'd done the output test for coil and injectors. So i fired up megatune and switched it to realtime.Calibrated the TPS, and made sure everything looked like a reading i should be getting.

Turn the key.... crank sputterTry it again.... crank sputter3rd time Crank VROOM!!!! SHE LIVES!!!!

won't idle so i have to keep blipping the gas to keep it running... then i realized that the hose to the MAP sensor had popped off the fitting as the map is reading atmospheric. All other sensors look fine, tach readout is great

Turn it off fix the map hose, she fires right back up. Still won't idle(not really sure if the fast idle i wired up is working or not). I screwed with the trigger angle some more, i'd started at 78, moving to 86 allowed me to let the car fall below 1000 RPM before it starts missing, so i just gotta tune the ignition somemore. But my laptop battery died... oh well more fun for tomorrow.

And here follows pics of my wiring job, it still needs to get bundled and ziptied out of the way.I apologize for the crappy pics but all i had available was my cellphone camera... so they are what they are.

and here's the msq i was using. http://www.geocities.com/kraze...7.txtUnfortunately i can only host on geocities at the moment, so i had to rename it to a txt. So you'll need to change the extension to .msq. Because i'm running the MS2/extra code you'll also need to download this version of megatune to open it.http://msextra.com/ms2extra/fi...r.exe

So for today i'm done, tomorrow i'll definitely have some time to screw with it and hopefully get a decent idle going.

[ZiG]

Awesome!

just ziptie the iat sensor somewhere for now. On a turbo car it needs to go in the coldpipe because the air is a different temperature due to the compression and intercooler, but on a n/a car having it ziptied in the engine bay somewhere in the general area of the airbox will be just fine. Actually I had to do that with the iat sensor in my Firebird when I installed a CAI. heh.

As for your trigger angle, have you checked it with a timing light yet? Just set megatune to hold 20* btdc and then adjust the trigger angle until you see 20* with your timing light.

As for your idle.. do you have the iacv hooked up yet? Or are you just trying to use the thermal fidle valve?

[krazydriver]

yeah i'm just trying to do the thermal idle valve for now. It has 12 volts and a ground but it might not be working right. If i can mess with the tune and get it to idle i'm good, if not i might wire in the IACV.

Once i can get it to hold a steady RPM, or idle properly i'll bust out the timing light on it.

I was gonna just jam the IAT up the hole where the resonator on the intake plugged in, but i got lazy and wanted to see if the car would start. That might be part of my problem because without the sensor attached it's accounting for a 170* intake temp, while the actual temp was about 55. I'll put it in tomorrow and see if it makes a difference.

[ZiG]

Woah, yeah, it would be thinking it's getting way less air mass than it actually is.

the thermal valve will stay open until it has had power through it long enough to shut. so once it's warm, it would die. It heats up pretty quick too. Leave it unhooked to stay open longer.

My landlord bitched at me for working on the car so much in the parkade, so i have to take it easy for a while. As a result, I still havent wired my iacv up. Alls I have to do is splice in the diode and connect the wire to the lead coming off the ms, so maybe I'll go do it in the middle of the night.

[krazydriver]

Found out why i couldn't idle, i set the injector open time too short... so they never really had time to open and the fuel wasn't being injected accurately.So i bumped the open time up to 1.5ms and it worked fine.

The fast idle thermo valve works great, car starts up and idles around 1150~1200 after a couple minutes valve shuts off and idle drops to ~800.If it's dry enough tomorrow, i'll put the timing light on it and make sure my trigger angle is set right.

at the moment idle AFR is 13~13.5:1 so i'll have to screw with that some to get the idle straightened out before i move onto the other bins.

[dwada]

Where are you guys getting your base maps from or did you make your own? I'm using the Spectre performance computer with MSD Blaster SS coil, the tach adapter & 6BTM box on a 91 240sx.

Thanks

[ZiG]

I generated a map that was good enough to idle the engine. Then I got a tune from someone else on la-t.org that was good enough to limp to the dyno, where I paid to have a pro tune it.

[480sx]

I had mine running well, i just couldnt get the thing to stop eating my starters with ill timed spark on startup. It was like the dizzy was to far advanced when it was trying to start up, and it was stoping the crank. Did you ever have that problem?

Wheres your MSQ, id like to look it over and see if mines different.

[ZiG]

Yeah, I've been having that problem too. Not too sure how to go about fixing it, but I haven't tried.

uhh i'll have to find hosting again..

[480sx]

Try this first, i want to see if it works.

Quote, originally posted by MS Forums »

the simple false trigger prevention method will not allow my engine to start. It just kicked back and would never quite catch. I put my poor starter through a beating!I ended up configuring the Advanced false trigger prevention time mask setting to 10-30%. The defualt 50% time mask would also not allow my engine to start.

Jsmcortina wrote "I need to look into this - the "simple" mode was supposed to be a copy of the built-in settings on all MS1 variants, that seems to work for everyone. I must have made an error somewhere."

There is some info on Advanced trigger options. simple mode does not allow my Nissan CAS equipped vehicle to start. I do believe others had problems with simple mode aswell.



Only MS2 has the false trigger setting so that would explain why people aren't running into it with ms1. that and megatune defaults the false trigger to simple. Try this out and let us know if it works!! if that's the solution i should be all set to install my MS2 next weekend.

[krazydriver]

had idle afr's set properly. But i was looking the other day and had realized megasquirt was doing like 40* of advance at idle.Long story short :

Trigger angle is not working for me. I can't change it to adjust the timing... so i've actually had to subtract from across my timing table to force the timing to where it should be. i'd read something that said that could be caused by the spark output being set wrong.... so i set mine to spark output going low(normal)...DO NOT TRY THIS!!!!

I was worried it wasn't right so i kept a finger on the vb921 and as soon as i felt it getting warm i shut the car off.. but i managed to fry my blaster SS. so now it's gonna be a couple of days before i can get another one.

then maybe i'll just load up a beta firmware and see if the trigger angle works.

[ZiG]

D'OH! That sucks. Yeah it has to be set to inverted.. And changing your trigger angle and NOT having your timing change? That's messed up.

[480sx]

Your doing something wrong, or the trigger wizard would change your timing. Did you try setting it at 72-78 to start then fine tune it?

[krazydriver]

D'OH! That sucks. Yeah it has to be set to inverted.. And changing your trigger angle and NOT having your timing change? That's messed up.

well i'd read on the msefi forums where someone had it set wrong and that was the cause so that's why i tried it atleast a friend of mine had a spare coil i could use.

480, when i'd first started my car it was set at 78. But 20* at idle was really about *43. My lungs are starting to clear up so i screwed around with it for much longer today, and found with the trigger angle around 105(? i think) that my timing would match.

It almost seems that i have to cycle the power to megasquirt BEFORE the trigger angle changes.... which kinda negates the whole trigger wizard... exactly like my problem has been.

[480sx]

Do you have your dizzy fully advanced? Towards the firewall is where it needs to be.

[ZiG]

That's freakin' weird. I don't remember where my trigger angle sits, but I know it's exactly the same as a local guy from my club that also 'squirted his s13, and I know it was somewhere between 105 and 110.

Oh and instead of subtracting from your whole table, I suggest you just change the trim angle number, which has the same net effect.

[krazydriver]

Do you have your dizzy fully advanced? Towards the firewall is where it needs to be.

I've tried that. Timing is dead on with the trigger angle set to 0 then. But the car won't start because it tries sparking WAY to early.

Oh and instead of subtracting from your whole table, I suggest you just change the trim angle number, which has the same net effect.

that's what i finally got working last night. I had a friend who came over and helped me for awhile when he dropped of his spare coil. Previously I've been on my own, which kinda makes checking the timing while tweaking stuff very difficult to do.

At the end of last night we had the timing dead on, and the idle is going fine. Car is tuned so i can rev up to 4k and everything looks fine. So i'm gonna take it for a datalog drive and just have logviewer revise my VE tables as it sees fit.

[480sx]

So do you still have the starting/early spark issue though? I was never able to resolve it.

[krazydriver]

well the above was me trying to solve that.I can't fully advance the distributor or it sparks early, so instead i just have to run the wicked high trigger angle so that the timing is correct.. but the cranking trigger is retarded enough it can start.

Car starts and runs fine now. I'm probably going to take it for a test drive today.

[ZiG]

Mine does that false trigger thing some of the time. it's kind of a random thing..

[krazydriver]

well i got in about an hour total of datalogged test drives yesterday. So my work is cut out for me this afternoon reviewing and changing what i need to.

Pretty much needs some leaning across the board. Also i drove it to my friends house and let it cool down before i drove home... and realized i really need some kind of controlled fast idle for warmup. The thermo valve just isn't cutting it.

I'm in his driveway revving the engine till it warms up... kinda pathetic.

[MAGILLA]

well i got in about an hour total of datalogged test drives yesterday. So my work is cut out for me this afternoon reviewing and changing what i need to.

Pretty much needs some leaning across the board. Also i drove it to my friends house and let it cool down before i drove home... and realized i really need some kind of controlled fast idle for warmup. The thermo valve just isn't cutting it.

I'm in his driveway revving the engine till it warms up... kinda pathetic.

Hey man Good job on the whole thing. You 480 and zig have done well to even go the mega squirt route, because there is so little support for 240's. I have been meaning to install a MS II, but i never have the time. The biggest thing is I can't afford to be without a car. It is good to see that when I do start I will have a few people to ask ?s