seth1001

Long story short - I updated my MS3 firmware and TunerStudio for the first time in about 10 years. The update wiped all the settings from my ECU and the old tune file is no longer compatible with the new software/firmware. I copied everything over manually from a really old tune file that I think was pretty close to the working tune, but my engine won't start. It comes close...sputters on start but won't actually run or idle. Can anyone take a look at my tune and tell me if anything is glaring? For all intents and purposes, it's a stock 280ZX N/A motor from 1980. Nothing fancy about it. Thanks. 2023 280ZX.msq

I'm not sure exactly what you're getting at. You seem to be implying that you can run a megasquirt box triggering off the coil negative with an MSD ignition system, which as I explained is not possible...for the reason I explained. I think you may have misread what I was saying. It's true the megasquirt can trigger off of a coil negative, VR, or hall sensor; though the board would have to be reconfigured for each one. The issue is simply that it wasn't working that way on my car. The coil negative wouldn't trigger the computer at all and the VR put out a very unreliable signal. And I don't have a hall sensor in my ignition system. Now I've got the MSD box, which WAS able to trigger off the VR, and the megasquirt receiving the tach signal from the MSD box's tach output. My problem now is that there's some kind of interference in the system, and I can't figure out if it's starting at the VR or coming from the MSD box or both. And because of that fact, I don't really have any idea how to go about fixing it.

That wiring scheme is actually not possible with an MSD box. The multiple spark discharge fires the coil multiple times for every spark discharge. If you wired the Megasquirt box to the coil negative with that setup, the megasquirt would think your engine rpms were about 4 times higher than they really were, which is why every MSD box has it's own RPM output which is what I'm using. It puts out the exact same square wave 12v signal that the megasquirt is looking for. I actually HAD to use the MSD because my megasquirt refused to fire off of the coil negative pre-msd box...presumably because there was too much noise in the electrical system. I don't have the money or justification to buy an oscilliscope at this point so...that's where we are. In response to the comment about the alternator, actually I just installed a brand new alternator about 2 months ago. I'm planning on getting some magnecor wires and a new coil to reduce noise but I can't imagine that alone would solve such extreme RPM spikes. Would a battery negative grounding kit increase noise?...I've got one of those on there. I don't have any idea what else could be causing so much noise in the system.

It's not running off the coil negative with my setup. The MSD box is being triggered off the VR and the Megasquirt is being triggered off of the MSD box.

I've spent the last 7 or 8 months working on my 1980 280zx NA...so far I've got MS3 v3.0 in there and it's working for the most part. Anyway, I could never get the stock distributor to get a tach signal to the MS3...it just wouldn't work. So I ended up getting an MSD 6al box to generate the tach signal and hopefully improve performance albeit slightly. For the most part it's been promising, but I'm having a huge problem with RPM spikes going to the MS3. I've driven the car a lot and come to the conclusion that the problem lies outside of the MS3 settings. I've tweaked the RPM lagging but the spikes are too intense to get around it that way. I also disabled the fuel cut to see if that helped...not so much. Basically it happens whenever I up the load, or up the RPM, or both. I can't drive the car above 2500 without getting spikes up to 30,000 rpms showing up in tunerstudio. It also happens a lot when I up the load, even if the RPM's are below 2000 or so. The rpms spike and the engine bogs down. So...that's the situation. The forum wouldn't let me upload so here's a link to the log file. Any suggestions for me? Thanks. http://www.mediafire.com/?ylma6va2rlrh48s

Yeah I had it hooked up the post the whole time...Nothing is working to get an rpm signal to this thing...It's getting to the point where I don't understand how people are buying these things when it's such a pain in the ass to get them to work.

It should be easier but apparently it's not. But looks like the VR setup isn't working either. It's really starting to piss me off. I've got the thing working fine on the stimulator and the spark is working fine on the car...I just can't getting any damn RPM signal to the MS. Also the FSM doesn't identify which wire is positive and which is negative...but it says the green wire goes to the "spark timing signal monitoring circuit" so I figured that was the one...but it didn't work. Moby: my logic is that if I can't get this thing to work on "fuel only", there's no reason to think it will work as fuel and spark. Plus I really don't like working with distributors because my understanding is not good enough to not destroy the engine while I'm dicking with it...and changing the distributor has got to be harder than getting this thing to work...but that balance shifts with every failure.

I've given up on getting RPM from the coil (-) on my 1980 280zx. It just won't work. So now I'm going to try and trigger it off of the reluctor. Does anybody know how I'm supposed to get to that thing? And how I'm supposed to wire it up? I've never messed with the dizzy before so I'd like to know what I'm looking for before I go digging in there. Some pictures would be great. It's an N/A...by the way. Thanks.

No I just meant nothing from the megasquirt connected to the positive side. I've confirmed that I'm getting spark to the plugs and voltage to pin 24 on the harness. Everything is set up correctly according to the guy from diyautotune...but still no rpm. I guess I'll have to set it up for VR input and pull RPM off the distributor.

Well I finally have everything wired up in my car. All the sensors are giving good readings and everything seems to be fine...but I still can't get any RPM indication with the megasquirt. Given my history of making little errors here and there I assume it has to have something to do with how I've got it wired. I'm running FUEL ONLY on a STOCK 1980 280ZX. I confirmed the board was good with the stim...though I had to jumper D2 to get a signal with the stim. I've tried it on the car both jumpered and unjumpered at the advice of one of the megasquirt guys from diyautotune. Still nothing. I've got pin24 (the grey IGN wire) running to the coil (-) and nothing else. Nothing going to the positive side...and nothing connected to pin36. I've confirmed continuity and that the plugs are firing. I've read all related posts and I've looked at every wiring picture in existence...and since nothing really matches my configuration...I haven't been able to be sure it's correct. Is this how it's supposed to be wired?

How do I do that?....What should I wire it to?

Hey fellas, I just finished wiring up my MS3 V3.0 into my 1980 280zx N/A...and needless to say it's not going too well so far. I'm gonna break down the issues into phases so it's easier to see the timeline of problems. Keep in mind that at some points there were some obvious problems but they were minor in nature so I was willing to move forward just to see if I could get the thing to idle. Phase 1: Before attempting to start Here my main issue was the coolant temperature sensor. I just used the stock sensor but I had trouble calibrating it. The values I input from this thread: http://forums.hybridz.org/index.php/topic/57800-280z-coolant-temp-sensor-values-for-easytherm/page__p__527871__hl__%2Bcoolant+%2B280z__fromsearch__1#entry527871 did not work right...it was reading at like...215 degrees F when it should have been around 60. So I got out the FSM and input the values from the graph for the 1980...still didn't come out quite right. So then I tweaked the bias resistor value until I got the megasquirt to read somewhere around 60...not the best approach but again...I just wanted to see if I could get the thing to start. Anyway...does anybody know what the values should be?...Or should I just get a new sensor from autozone? Phase 2: First start attempt No rpm indication. I figured it was something stupid...like...I hooked up the wrong wire to the negative terminal...which I'm pretty sure I did. I went back at looked at the diagram on this link: "http://www.msextra.com/doc/ms3/hardware.html#wiring" then I saw that it was pin36 that went to the coil (-)...but the wire colors didn't match...I saw on another drawing that it was a grey wire...so I thought the grey shielded IGN wire was the thing to hook up there...anyway...I swapped it to the pin 36 wire and tried again Phase 3: Second attempt When I first turned the key to IGN...the fuel pump kicked on and wouldn't go off...seemed weird so I killed the IGN and clicked it back on...pump went off...so I guess that's good. Cranked it a little to see what would happen...NO RPM indication but the engine fired and started idling...albeit quite roughly...I think it may have been burning fuel already in the cylinder cause without RPM the megasquirt shouldn't be firing the injectors at all...anyway...then the engine died and the garage stunk of gas from the rich burn and the fuel pump refused to kick on again...it might be broken...never got any RPM indication...also the power to the MS kicks off if I crank too long. Which makes sense because even in modern cars pretty much everything loses power when the starter is running...so I'm a little confused as to how its supposed to work while starting. Anyway, I've got the board all set up for coil negative rpm and I got it to work with the stim. In order to get it working I had to jump the D2 diode because the stim didn't have enough voltage to push through it. I pulled the jumper off when I put it in the car because it's my understanding that that's what you're supposed to do. Any thoughts on the RPM not showing up? I wired the power for the MS and my wideband sensor to the ignition switched wire going to Fuel Pump relay #2...any thoughts on that?...Is it...good? I'm really not sure...I couldn't really find any recommendations on where to get power so I just stared at the wiring diagram in the FSM until I found something that seemed reasonable. So that's about it...I'm fairly stuck right now...don't really know what to try at this point. I might think of something eventually but it would surely move quicker if you guys could point me in the right direction. Thanks. PS. Sorry it's a long post

Well here's something interesting. I clipped the wires that go to the individual fuel injectors after reinstalling the dropping resistors and all that. Then I turned on the ignition so I could check the voltage and figure out which wire I should connect to the megasquirt...but both wires were testing at 13V...I don't know what's going on here...I guess I should take a look at the wiring diagram but that things a pain in the ass to look at. Does anybody know how I determine which wire to hook to the megasquirt?

I think the turbos didn't have them because they had different injectors that didn't require them...

Oh that's right...it should just be the "-" wire on the injectors that routes back to the ECU...makes sense...Any comment on the firewall routing?

Moby: Yeah the ZX's all had dropping resistors as far as I know. Well that simplifies matters. I've tested the resistors and they're still putting out 6 ohms of resistance so I guess I'll just hook them and and splice the wires at the injectors. I don't really like the idea of using the old wires but I guess it's okay. I also don't like having to use the old EFI computer to put out the voltage to the resistors...but as long as it works I guess. The wiring for everything else is pretty much self-explanitory but I'm still not sure how I should get the wires past the firewall. I've done some searching but haven't found anything good yet. What did you guys do? Did you drill new holes or use ones that were already there? Also I've heard that wide-band O2 sensors have some issues with interference...did you guys have to drill a separate hole for the O2 sensor wire and kind of...keep it separate from the other cables or something?

Well riddle me this...couldn't I just leave everything wired up through the stock dropping resistors the way it is...and then chop the negative sides and splice them to the megasquirt...bodda bing?...or does it not work that way?

Where did you guys get your switched wire? I know the dropping resistors have a pair of switched 12v's going to them but I may have to use those resistors somehow if I can't find any others...which I haven't so far...radio shack doesn't have any. I think I'd rather get rid of those 30 year old things and build some sort of resistor box and just mount it somewhere...I've read some posts on the matter but I can't really visualize what they're describing...I guess I could mount the resistors on the fuel rail...with some..mighty putty or something. Any suggestions?

I see...interesting...so this is the way it should be?

I'm getting close to starting the wiring for Megasquirt into my 1980 280ZX N/A. I just wanted to post this sketch I made and make sure that I have the concept correct. Does the picture below look right?...Do I need to wire anything differently? If so...please describe it to me and I will make a new picture until I have it correct. Thanks.

Man alive, what a pain in the ass. Anyway...I figured out what the problem was. Apparently my stim doesn't have enough voltage to push the tach signal through the D2 diode...so I had to jumper the diode. Now it seems to work like a champ. I'll just have to unjumper it before I put it in the car and hopefully it will work. I found the answer in the MS2 troubleshooting section...which is something I've been trying to avoid so I don't confuse the 2 stuff with the 3 stuff...considering I've never used either before. Now I just have to figure out how to wire the damn thing in. I'm confused as to how I'm supposed to wire the thing into the ignition system...do I just grab an ignition wire where I can and splice it in there?...maybe with a fuse?...doesn't seem right to me but anyway...I've seen all the cartoon wiring diagrams but an actual photo of the power and injector wiring on a car would be great...anybody have one?

I don't know of anyone around here that has a megasquirt...is there some way to check the pins with a multimeter and see if the stim is putting out rpm?...also I guess I could just hook the thing up to my car with the wiring harness and just hook it up to the coil negative....try starting the engine and see if a tach signal shows up on the screen...

Alright I reflashed the board with the firmware and got that light to go out. I'm not sure why it came on in the first place but it's out now so who cares. I'm still not getting any rpm indication. Everything looks good as far as the assembly goes...What could I possibly be missing at this point?

I assembled it myself...everything seemed fine during initial tests and that light seemed to come on randomly too....that is to say I don't think I changed any settings that would have caused it...but I don't know. None of the chips seem to be backwards either. Here's a link to a progressive series of pictures I took during the assembly. Maybe you can see if something looks messed up. http://www.mediafire.com/file/om7670o60u7brwd/MegaSquirt%203%20Build%20Pics.zip Thanks.

Well I finished all the work and I put the 22v diode in there but I still can't get any RPM indication. Also the left diode on the mainboard is staying on all the time now...it was doing that shortly before I finished setting up the board for coil (-), but not during initial testing of the board. To clarify...I finished the whole thing (or I thought I was finished)...then I hooked it up to the stim to check the inputs. Everything worked except for the RPM since I hadn't set up the board for that yet. After fiddling with some settings over a couple of days nothing really changed. Then one day that left diode lit up when I hooked up the sim and stayed on. I didn't think much of it...I just kept trying to get the rpm input to work. Now the board is all set up for coil (-) and tuner studio is set up for "fuel only"...but still no rpm indication and that left diode is stuck on. I can't find anything that will tell me what it means. Any idea what the problem is here?