Zmanco

Ok, for the third time within this thread I'm going to point you to the diagram in post #14 for how to connect the dizzy to the relay board. Side note: I'm frustrated that you continue to ask questions without making an effort to answer them yourself with what's available on the megasquirt site or even what's already been posted to this thread. I'm going to step away from this thread for a while and leave it to others to answer your questions if they want. Edit: the answer to your question about pin 15 is yes, that's the pin that connects to the dizzy signal. What other pin could it be?

Ah, I vaguely remember there being an option in the assembly instructions. Since I don't remember clearly I'd suggest you go back through the instructions if someone else doesn't chime in. But again, increasing current flow through the injectors is more likely to increase EMI than to reduce it.

Are we talking about the same resistors? I'm referring to the ones that are in series with the injectors to limit current for non-PWM applications with low-z injectors. In this case the resistors are too large for the relay board and will be mounted elsewhere (not sure where they were on the 280z - perhaps someone else can chime in here). If you pulled your own wires from the relay board to the injectors then you don't have any resistors (unless you added them elsewhere).

Glad to hear the caps are (so far) showing improvement. That would confirm it's a noise problem. Not sure about this: if you're running high-z injectors then you don't need the resistors in the first place so yes, you can/should short them out (same as removing them). But I don't see how this would reduce noise in the system that contributes to your reset problem. In theory the resistors are limiting the current which should be reducing EMI. Still, it's worth a try - just be sure they really are high-z

Use any one of the 4 screws on JP2 which provides +12V to the injectors. You should have at least one of them unused. BTW, you might want to find a place to mount a terminal strip so that you can also power the O2 sensor and calibration switch the same way. Here's a picture of how I did it. You might also want to search for a thread cygnusx1 started when he did his install. His was similar and might give you some more ideas. BTW, make sure you are labeling the wires. If/when you have to go back and troubleshoot you'll be glad you did.

You didn't say what carbs you're using, but I'll assume they're SUs. From what I've read, the stock air horns on the air cleaner are pretty good already and unless you've heavily modified the engine (in which case you probably wouldn't still have the SUs), there's little to be gained with other horns. FWIW, I had notably less power at high revs when I tried running without them.

If your question is if you can use the ballast resistor in place of the resistor in post 14, the answer is no. Ballast resistors are typically only a few ohms and you need one around 1k. As for a power source for the dizzy, why not pull power from the MS relay board? In general, it's a good practice to pull power from a single point and also tie grounds to a single point. I don't see why you couldn't use the hot side of the ballast resistor, but since you have to pull a wire for the trigger signal anyway, why not pull all 3? Troubleshooting later will be easier too as you're not relying on the factory wiring which after this much time and previous owners may not be in good condition.

There are several ways to assemble the V3 board based on what type of trigger you use. I suppose for some it might be easier to use the GM HEI vs. modifying their board. I would wire the distributor according to post 14 - that's the way I did it. The E for extra refers to a different version of the firmware running on the MS board that gives additional features. Before you go any further you should spend several hours on the MS sites reading up on this. MS is increadibly flexible with many options, but that means you have to make decisions which are best done when you're informed. It's beyond a thread like this to cover the pros/cons and tradeoffs of the various approaches you can take. Better if you read up and ask some questions - that will keep the threads to a reasonable length One last thing: shortly after I finished my install (and while it was still fresh in my head) I did a writeup that covers some of this. You might find it helpful: http://forums.hybridz.org/showthread.php?t=122277 Good luck!

You can trigger MS1 directly from the turbo distributor so you don't need the GM HEI module. Since you already have a V3 board, if you're open to upgrading to MSII you could eliminate the MSD6 and have MS drive the coil directly. http://www.megamanual.com/ms2/vb921.htm The benefits of the MSD multiple spark feature is debatable, and they don't have the best reputation for reliability. MSII also supports MSII/Extra code including 16x16 tables for fuel and spark. There's nothing wrong with MS1 and MSnS/E, but the next generation is much improved. At this point all you would need is to buy the MSII processor which is about $90. And if you're thinking that you'll just start with I and later upgrade to II, you can do that, but keep in mind that you will have to retune from scratch. The fuel algorithms are different. Again, I'm not saying you need to start with MSII, just that if it's in your plans for later, it's best to do it now.

I'm having a similar situation with 84 300zx rotors on the early 4 bolt hubs. I have a new set of rotors on order but want to get some shims in advance to have on hand if I need them. Anyone have a good source for shims that will work in this application?

If you set the PWM Current Limit to 100% then I don't think there would be anything gained by trying to modify the circuit. And in case you haven't already checked, make sure you have the PWM set to 100% since you have high Z injectors. Now that I think about it, did you tell us which version of MS board you're using? v3? I just skimmed the posts but didn't find it right away.

I'm running with 280zx turbo injectors (low impedance) and had issues with the injector drivers overheating (I think that was the root issue) and so added resistors which solved the overheating issue but not the resets. I swapped the spark plug wires a month later and that finally solved it. My suspicion is that since it's a noise problem, it's exacerbated by a combination of issues which probably include the poor flyback control design, any non-shielded sensor wires, lower quality spark plug wires, etc. I doubt there is a single silver bullet that solves this type of issue but rather it will go away when a lot of best practices are followed. That said, jeffer949 I feel your pain. I know how frustrating it was for me and you've put in so much effort and $$$ already. But stay with it - you'll eventually solve it and I'm sure you'll be quite happy with the outcome.

Zredbaron, I've since gone on to megasquirt, but when I switched to a distributor that was controlled by the MS (in other words, I could choose my own advance curve via the laptop) I found that by running a lot more advance at idle and low revs (<2500 rpm) I had significantly improved drivability. For example, I'm running 20 degrees of advance at idle and have full advance of 35 by 3000 rpm. This is with what most call a stage III cam. My point in telling you this is that I think your theory that the stutter is tied to spark advance is indeed correct.

You didn't say what your fuel delivery system is, but I'll assume it's the stock SU carbs. 5 psi is a bit on the high side as the spec is 3 psi IIRC. But you may find that it's ok with that particular pump. Bolt it up and if the carb floats don't leak I'd just run with it. If not, don't waste your time with the cheap fuel pressure regulators for $20 at the parts stores. I found that they need a larger difference between the inlet and outlet pressures to work well. They can't handle dropping 5 psi to 3 psi reliably. In the end I went a different direction so can't recommend a specific brand of FPR, but I think you'll find it's cheaper to just buy a different pump than to buy a high quality FPR.

Last year I ran with the Kumho MX 225/50-16 and was very happy with them. This year I switched to the Dunlop Direzza Star Spec due the SCCA autocross guys raving about them. I'd say they are at least as sticky as the Kumho and seem to turn in a little better on my car. I've only had one track day on them, but to my eye (no measurements) they showed less wear than the Kumhos did after their first day. So far I'm very happy with them and they were only a little more than the Kuhmos from Tirerack. BUT ... if you're going to drive in the wet, I'd be wary of either tire. They have big solid tread blocks which aren't what you want for wet weather. Mine is a toy so I don't care about wet weather, but if you do, I think there are better solutions (probably more costly too).

Ryan, a few additional thoughts beyond what others have posted: - Is the tach getting its signal from MS or the coil? If it's the coil, then it's very interesting that the tach goes dead shortly before the engine dies. That would suggest to me that the spark is fading and the tach loses the signal followed shortly afterwards by the engine dying. Culprits could include the driver on the MS board, the HEI module, or possibly even the coil. I'd start with the HEI module mainly because it's easy to swap and cheap. - I suppose too much play in the dizzy might contribute too. I have a spare '80 zx dizzy that you're welcome to borrow if you want to try a swap. But unless there's a lot of play I doubt this is it. - I noticed that your MAP reading is 73 before the engine starts. At my home (elevation ~6300 ft) I typically see ~80 so that might be a clue that something is off with your MAP sensor unless you were up at the ski resorts. But I can't imagine how that would cause this given the datalog doesn't show anything abnormal. I wouldn't suggest going to EDIS until you know what the issue here is. Adding more unknowns is only going to make it harder to trouble shoot if it doesn't just "go away".

Glad to hear that you've slayed this dragon! EMI is just plain tough to solve, but with perseverance it can be solved. I know how satisfied I felt when I solved mine, and yours dragged on longer and harder. CONGRATULATIONS!

I've been going on the assumption that your issue is due to resets. But you used the term "break up horribly" again. Without trying to pick on your words, I'm wondering if you've got something else going on. Have you taken a datalog and looked at your spark advance and injector PW values while the break up is occurring? If there's a problem with your MAP sensor I would expect to see that show up too. Perhaps you can post the datalog and let us know what times to look at?

Ideally you'd find one off of an old Z such as the cap that's next to the distributor or the one attached to the alternator. I'm not sure of their exact value, but you could also pick up an electrolytic capacitor at Radio Shack. Probably go with a 100 uF rated at 100V. Or maybe 50 uF? I'm not sure what Nissan used, but the exact value doesn't matter as much as you'd think. The cap is basically acting as a short circuit to high frequencies and an open to DC. Smaller values have more effect at higher frequencies. Anyone know what values Nissan used?

I'll add that the routing of sensor wires can play a role in allowing noise to creep into the MS system. Most people focus on the power and ground wiring, and that's important, but EMI can affect any wiring, and long straight runs are quite susceptible (they act as an antenna!). One good practice is to twist the pairs to/from the sensors, or even to switch to shielded cabling. I'm not saying that will solve the issue in this case, just saying that eliminating EMI is tough and involves a variety of best-practices. Jeffer949, where do you have the MS unit mounted? Is the cover on it? Where is the relay board mounted (if you used one)? Do you have any of your wires running near the ignition coil? How about near the spark plug wires (aside from where they cross over valve cover - or did you route them some other way)? Do any of your wires run across openings (free air) as opposed to following along the metal of the car? Just throwing some things out there to look at. It's one thing to have resets, quite another for the MS firmware to become corrupted and require a reload. At the risk of stating the obvious, something is still quite wrong here.

Chris, here are 2 MSQ files: MS2E 2.0.1 is the last version I made for use with the RELEASED version of MS2. MS2E pre-beta 2.1.0 is from the current PRE-BETA build. Most of the improvements are in the area of IAC control, so if you're just getting MS up and running, I would NOT recommend starting with it. There is not supposed to be any difference in fuel calculations for the new version, BUT there is a bug (that I didn't know about) in the released 2.0.1 that under-values MAPdot for AE by a factor of 10. This bug was fixed in the pre-beta so I landed up retuning AE from scratch. Basically the AE was triggering almost all the time at idle which caused a rich condition. Just keep this in the back of your mind for when you eventually upgrade the final released version of 2.1.x. MS2E 2.0.1.zip MS2E pre-beta 2.1.0.zip

Chris, I'm currently playing with the 2.1.0 beta release so won't send you the msq (unless you want it), but attached are the VE, AFR, and spark tables. Engine is L28 with cam, headers, shaved P90, etc. ms2e.zip

A simple way to check for vacuum leaks is to spray carb cleaner on the questionable areas with the engine idling. If the idle speed changes you've found a leak.

Huh? You put larger idle jets in and now your engine is idling slower and smells bad - both symptoms of being too rich. I don't understand the basis for your question? As for cold start chokes, just leave them open and forget about them. I was able to start on 20 degree F days in Colorado without them just fine. The reality is that once you get the webers dialed in, you'll find they are always on the rich side - they will deliver the best performance and drivability when tuned that way. The cold start chokes will just be a distraction for you. If you get the warm temp setup dialed in and THEN you find that you need help with cold starts, only then begin to mess with them. You've got enough to work with right now

55Fxx is awfully large for an L28. When I had triples I ran with 45F6 (albeit I'm at altitude). IIRC, the F number determines how much air is bled in and that's probably where you should be making changes. You might want to go back to a 50F6 if you were too lean with the 50F9.