trwebb26

A little update on my problem: http://www.msdignition.com/forum/showthread.php?t=7518

As far as hardware goes - I reccomend buying an 82 or 83 280zx optical distributor. Make sure you get the oil shaft with it because you'll need it for the swap. After that - it is just a bunch of wiring and settings to get it right. We can help with that once you get the hardware you need. I would get an MSD blaster 2 coil to match up to that MSD box, too. Otherwise you have to mess with ballast resistors and other crap like that. Do you have any specific questions that we can help with other than "tell me how to do it"?

trim angle is set to 71. The dwell is set at 50% cuz i'm using an MSD. It is capacative discharge and is suposed to have a fixed dwell (from what I've read).

So I bought a new MSD and installed it last night. Now the car does something different - but still not correct. As before - it starts and idles fine with the timing correct. The second you touch the throttle - the timing jumps to ~60 degrees. This happens even if you have the timing fixed at a certain degree. If you let off of the throttle - it goes back to the correct setting. I guess I'll send my Megasquirt in to be looked at?

My problem happens whether the car is hot or not. I can let it idle for a half an hour - with NO problems at all. Timing stays steady and everything does what it is supposed to. When I rev the engine up - something happens. The timing will stay steady, but the car won't rev up. Then if I open the throttle again... the timing will skip to around 60+ degrees and stay there for around 10 seconds and then start skipping all over the place. For giggles - I tried a new coil... It did the exact same thing. I don't have any errors when I start up megatune.

Well... The tach signal looks good. The output of the megasquirt looks good. The output of the MSD looks ok... but it is really tough to tell because of the frequency of the signal. It is just a pulse instead of a wave - so it is tough to tell what is going on. My latest guess is that the MSD is bad. I hate just buying parts to test stuff out, but I don't know that I've got much choice.

Can anybody help - or give some opinions?

So I decided to just set the RPM fixed at 30 RPM to test Tony D's theory about "dropped throttle". It seemed to run much better... the timing became a tad less eratic. So I decided to rev it up high and all of the sudden the timing skipped to the next trigger in the distributor and got a huge BANG... big backfire:malebitch . I now believe that my megasquirt and MSD box are fine - as they act perfectly ok when the timing is correct. I now blame the distributor for a crappy square wave signal at high RPMs. Anybody disagree? I borrowed a scope from work and I'll check to see what the square wave looks like on the input to megasquirt. Any reccomendations about maybe changning my pullup resistor to a different Ohm value to be less sensative at high RPM's? One more thing. When I ran the wires for the distributor - i cased them in the braided sleeve that RS-autosport sells. I grouned the steel sleeve at the megasquirt (not the distributor). I know that you aren't supposed to ground it at both places (ground loop)... but I'm not sure if the grounding should be reversed. Should I have grouned the shield at the distributor? Does it make a difference? I'm a mechanical engineer and the one or two circuits classes I took have long since been forgotten. Thanks... I feel like I'm getting a lot closer! Almost there!

I'm not running solid core wires (taylor spiral-cores) It seems like tony D may have the ticket. It seems to be advancing to the next terminal in the cap - advanced to around 68 degrees (10 degrees less than my trigger angle) Are you running an MSD too, Tony? Did you ever put a timing light on it when it started to go crazy on you? Like the movie shows - it stays right around the 68 degree mark, but seems to skip around for some reason. Can you export your timing map for me, Tony - so I can take a look. Meanwhile - I'll mess with the high vaccum bins. Clifton - look at the tail end of the log... I was opening the throttle (hence the loss of vacuum and increased MAP), but the RPM's were staying in one place - meaning that then engine stopped responding. olderthanme - what do you mean by "dropping spark"?

Very wierd... With the megasquirt on - it reads 4.0 volts - but if you unplug it - it goes to 12 volts. How is that even possible with the pullup constantly feeding it 12v? Can somebody check the voltage at the dizzy with the megasquirt on - and the car off to check if this is correct?

Yes

With a properly installed 1K pullup resistor installed on the G/B wire as is shown in Moby's sticky - what should the voltage of that wire be if you check it at the distributor (with the car off)? I've only got 4 volts? The black and white wire has 12v.

Bump... bump... come on - nobody has any advice?

If you were having trouble with the movie - I've changed the location to another server. Please try to download it again. http://www.fileden.com/files/2006/8/28/191641/Megasquirt_problem_small.wmvFree file hosting from File Den!

unfortunately not.

I've been fighting my megasquirt for a couple of months now. I just can't figure out what is going on. About my setup: 78' 280z MS v3.0 board MS&SE 83' turbo optical dizzy Using (-)D14 to trigger an MSD6a to an MSD blaster 2 coil. As you'll see in the video - everything runs great when I first start the car. Then the timing will go to hell. It seems to be heat related somehow. Here is the movie: EDIT: http://www.fileden.com/files/2006/8/28/191641/Megasquirt_problem_small.wmvFree file hosting from File Den! Here is my MSQ (remove the .txt from the file name) http://www.geocities.com/trwebb26/280z_problems.msq.txt And here is a datalog of a similar time that this happend. You can see that it is fine at the beginning - then the MAP will change, but the RPMS stay put. http://www.geocities.com/trwebb26/datalog200608271842.xls The tach signal for the guage in the video comes out of the MSD box. I took video of it to show that the problem is either in the megasquirt or the MSD. I think that is pretty sure-fire evidence that the coil is not at fault. I've kind of run out of things to try... The only things I can think of are to send my megasquirt back to have it looked at - or replace my MSD box. Please help!

I have a v3.0 board running MS&SE. Everything works fine except spark output. I started out having the VB circuit drive an MSD 6a - to an MSD blaster 2 coil - to the 83' optical dizzy. The car responded very well for a few minutes, but would then start ignition misses and die. If you want a few minutes - it would start back up and run fine. There are several other who have had this problem that I've found on this forum and others. After a bunch of searching - I figured out that I don't even need to use the VB circuit to trigger the msd box... I could just run off of the negative side of the D14 diode. I rewired the megasquirt - removing Q16 (the IGBT coil driver) and now the car don't respond like it is supposed to. I know that I'm getting spark because I CAN start the car... but the timing is WILDLY off - and it only runs on a few cylinders. My wideband O2 reads nothing but 10's (the minimum reading) and there are big puffs of atomized gas coming out of the tailpipe... It smells like raw gas BAD. So I guess the good part is that I'm getting SOME spark. I've tried inverting the spark output, checking for cold-solder joints on the board, messing with the settings in megasquirt, several dwell settings (it is currently set at fixed-50%). At this point I don't know if I'm missing one little thing in the software, if my board is wired wrong, something is fried in the board, or what is going on. I'd appreciate any troubleshooting ideas as I'm about tapped out. Thanks!

If I understand it correctly - there are three choices for input... #1) Hall/Optical that takes the square wave input from a Hall sensor, optical sensor, or points (installation 50a in the manual) #2) triggering off the coil - but only if you are not controlling ignition timing (installation 50b in the manual) #3) VR takes the AC signal from a variable reluctor sensor and converts it to a square wave for use by MegaSquirt (installation 51 in the manual). I'm trying to decide if I should be using option #1 or option #2

But is says that you can't control ignition if you use that method (configuration 50b). I'm thinking that the only correct way is by configuration 50a (optically). My problem is that I expect it to have been wired by the 50a configuration - but my board has the 50b.... ???

When assembling a v3.0 board with the plans of using an MSD box for ignition - do you use hall/opto wiring (step 50a) or "trigger off of the negative terminal" (step 50b)? http://www.megamanual.com/ms2/V3assemble.htm#input I ordered my megasquir pre-made and I'm not sure if they wired it correctly for my application.

Ok... I did what I said I was going to... and the car will barely start up. If I put my foot on the go-pedal it will run a little, but the timing is WAY off. It smells like unburnt gas pretty bad. Any suggestions, now?

Great... Thanks for your help, Moby!

Holy crap do I think I've got it figured out... I had the board apart inspecting it for cold joints - and I thought I'd just check to make sure some of the components were in the right spot. Well... My board is wired like this: But I'm running an MSD - so I think it should be wired like this: So I guess my board is wired all screwed up (I ordered it pre-made from rs-autosport). To fix it - I guess I should: - Remove Q16. - Remove the jumper from IGBTOUT to IGN - Remove the 330 ohm resistor from R26 to (-)D14/wire lead & Remove the lead from (-)D14 to IGBTIN - Add a lead from (-)D14 to IGN. Does this sound right? What do I do with R43 & R57?

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http://forums.hybridz.org/showthread.php?t=112594