All Z's

Matt, thanks and I will try and get a datalog ASAP. Also, I will try some different wires to see if that helps. Thanks, Kyle

If you read my last post I stated that the main relay has been bypassed with a jumper wire and power is now coming directly from the battery. Thus, I have eliminated the relays as possibilities for causing the resets. Also, with a laptop connected it is obvious that MS is counting resets. I was under the impression that MS does not count losing main power as a reset, only processor resets that occur while the unit is powered, correct? The only way that this could possibly be a power supply problem is if there was some other component in the relay board (besides the relays) that is interupting power to MS. The battery has not been overcharging either, I get no more than 15.0 volts using a DVM while driving the car. Overcharging alternator was one of the first things that I looked for... Thanks, Kyle

Well, I tried a few more things with the car and no luck. I bypassed the main power relay and fuel pump relay both using jumpers to power the respective circuits and my main power feed comes directly from the battery. I also added an inline noise filter to the main power input. The problem did not go away for me though. Disconecting the alternator seems to alleviate the problem and the car will run fine, albiet not for too long as I run off of just the battery. I do not believe this to be an noise issue with the alternator as I have both the noise filter and have swapped the alternator twice now. I believe it now to be an overheating issue in the MS box itself. My theory is that the car runs longer w/ out the alternator connected because the battery voltage being slightly lower is keeping the MS from getting quite as hot as it would with full voltage being applied to it. I have checked and rechecked my dwell and injector settings to assure that I am not overheating the drivers due to improper programing. The settings I am using have worked just fine for 2 years or more on a couple of my cutomers cars (similar setup to car w/ the problems) with no problems what so ever. Also, the problem only occurs after about 10 minutes of highway driving and takes much longer to occur with just city driving. When MS does start to reset I can pull over and the car will usually idle just fine. Then after a 5 minute or so of idling it will drive fine for another few minutes before acting up again. When the problem occurs the car will idle fine but the more throttle I feed it the more frequent the resets become (up to 1 or 2 per second at WOT). I believe the car to be resetting because I lose everything (RPM, pulsewidth, etc) when viewing megatune. At idle everything seems better with very few resets. So what is the issue with this car? Aside from a component in MS itself do you think this could be a firmware issue? Should I reboot with a different firmware version (currently running 2.68)? Thanks, Kyle

Thanks for the info, I did not think about the fact that the main relay is not controlled buy MS itself. More things to look at now. I will let you guys know what I find. Thanks, Kyle

I have verified that both the main relay and fuel pump relay cycle on and off together. I will verify later if MS is counting resets or not and let you guys know what I find. As far as the grounding goes I have checked and rechecked the grounds and they all seem to be in ggod shape. I have multiple ground straps from engine and battery to the chassis and a good ground for MS directly to the chassis with less than .05 ohms of resistance showing on my meter. I have not checked the relay yet but will first thing tommorow. I will also double check that the switched 12v does not drop out at all. The thing that makes me wonder is that the car runs just great for the first 10 minutes down the highway and then will suddenly start having fits. Also, it did just fine for several months after the install and is just now acting up. It seems as if there is an electrical component involved that is acting up when it gets hot. Thanks, Kyle

Anyone think it could have anything to do with corupted firmware? Would it be advisable to try that just in case? Kyle

First, sorry for the long post but I want to be very complete in my description. I am working on a MSII install for a customer that has had a problem occur just recently. He has been successfully driving the car w/ MS for the past 6 months or so with no problem. A couple months ago the car quit on him and didn't restart for about 30 minutes. I found no faults and the car ran fine again for another month and did it again. The problem has now progressed to the point that it happens within 10 minutes of driving. The car resets rapidly on and off, you can hear and feal the main relay firing like a machine gun. I would guess that it is reseting 120 time or so a minute (~2 per sec). It only acts up under load for the most part too. Sometimes when it resets on the highway you can pull over on the shoulder and it will immediately free rev perfectly (not always, though). Then if you give it a 10 min rest (car turned off) on the shoulder it will drive again for a little while and repeat the above senario. In playing with the car I have noticed that with the alternator disconected completey I do not seem to have the problem, although I can only drive so far on the battery alone. I have changed the alternator already w/ a new Nissan OE unit for a 280ZX. I already plan on getting noise filters for the power wires going in to MS. Anyone have advice here? I just have this feeling that there is something more to my problem than a dirty power source. Here is a little info on the car: '77 280Z, N/A 280ZX engine with only minor mods, '83ZX-T distributor Info on the MS setup: DIY Autotune v3.57 board with MSII processor, MS relay board, VB921 firing coil directly, v2.6 software (have tried MS extra as well), board is jumped for optical input. Thanks, Kyle

The pots are completely open already. I changed the distributor pickup and now the tach signal seems to be pretty clean. It still acts up a little but is not nearly as bad. Thanks again for the input and I will keep eneryone posted on my progress. Kyle

The green wire is in fact connected to the shielding for the tach signal wire. Red wire connected directly to pin #24. And the shielding is in turn grounded inside the car very near the point where the tach signal wire is connected to the relay board. It shares a ground point with the main ground for MS. Grounds have been checked and rechecked for continuity and show 0.1 or less ohms of resistance. Thanks for the suggestion though, Kyle

Sorry to not get back to you sooner Matt, been very busy w/ school. I will try to post an msq for you asap. I now have the trigger offset set so that my timing is accurate w/ a timing light vs. MS readout. My offset ended up being -59. Seems strange to me but it works so far as I can tell... The only problem is that I am still losing a clean tach signal at anything over 3k rpm. On occasion it will rev past there nearly to redline but 9 times out of 10 it doesn't. When the car will not rev the tach is not dropping out to 0 rpm but is bouncing between 3k and 10k+ rpm. Any thoughts? Thanks, Kyle

I have a customer's car at my shop that I can not set the trigger offset angle on properly. My problem is that when I adjust the trigger angle it does not change the engine's ignition timing. This can be verified using a timing light with the engine running. I have tried offsets from -10 to 180 and everything inbetween with absolutely no effect on timing at all. The only way for me to get the car to run properly is to set the entire timing map in MS to 55 degrees of timing or more. 55 degrees in the timing map will get me to about 15 degrees of actual timing verified using a timing light with the engine running. With the timing set like this the car runs great until 3k rpm and then the tach input goes crazy. Anything over 3k will make the tach (in Megatune) jump wildly between 3 and 14k rpm. I believe this problem to also be related to my offset angle too. Here is my theory why. Anything below 3k gives me a perfect steady tach input signal. Also, if I take timing out of megasquirt (from 55 deg to about 40) the car will run poorly due to low ignition timing but it will then rev past 3k rpm without losing it's tach signal. This is very frustrating to me and my customer. It is my third install in a Z and I have worked with several other systems in early Z's and have never encountered a problem like this one. Here is a little info on the car: '77 280Z, N/A 280ZX engine with only minor mods, '77 VR distributor (green wire grounded and red connected to pin #24 via shielded wire) Info on the MS setup: DIY Autotune v3.57 board with MSII processor, MS relay board, VB921 firing coil directly (spark output is inverted), v2.6 software (have tried MS extra as well), board is jumped for VR input and I am triggering off the rising edge of the tach signal. I have followed all instructions for setting up the VR distributor on megamanual and on this site as well. If I have left out any helpful info let me know and I will post it up. Any advice on where to start on this problem would be greatly appreciated. If you are local (DFW area of TX) I would be glad to buy anyone who helps a few beers to show my appreciation.... Thanks, Kyle (w/ All Z Car Specialist)