All Z's Posted July 30, 2008 Share Posted July 30, 2008 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 Quote Link to comment Share on other sites More sharing options...
All Z's Posted July 30, 2008 Author Share Posted July 30, 2008 Anyone think it could have anything to do with corupted firmware? Would it be advisable to try that just in case? Kyle Quote Link to comment Share on other sites More sharing options...
Zmanco Posted July 30, 2008 Share Posted July 30, 2008 I had occasional resets (not 120 per minute!) that I thought were noise related and tried most of the electrical filtering and wiring solutions with no success. Then I read about someone who had found that their spark plug wires had degraded and were emitting more EMI. Apparently the best wires for minimizing EMI are from Magnecor and so I tried a set. I haven't had a single reset since. I can't say this is the source of your customer's problem, but failing wires would explain how it's getting worse and might explain why it happens when heat builds up under the hood. FWIW, I went with their racing set which has the best suppression - their part number 6524. They weren't cheap, but they're supposed to last longer as well. So far I have 5k miles, too soon to tell... Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted July 30, 2008 Administrators Share Posted July 30, 2008 When I was working through my MS reset issue, in my research on the subject I did find where others have found a noisy alternator will cause MS resets. Could it possibly the alternator took dump, i.e. bad diode/s, regulator, etc? Just a thought... Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted July 30, 2008 Share Posted July 30, 2008 I dont get resets but I have had my car stop running with strange tach behaviors only to go back to running normally after a 25 minute cool down period. Sounds similar and I have a similar setup. It happened with a noise filter and without. Happened only twice in about 5000 miles with MSII. Best clue so far is that mine could be due to a failing pickup inside the dist. It could be plug wires going bad with heat also. Mine is so intermittent that I can't diagnose it. To circumvent, I am in the process of switching to Ford EDIS-6 ignition. Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted July 30, 2008 Share Posted July 30, 2008 If the main relay (as opposed to the fuel pump relay) is clicking on and off, there's only three things that can cause that. Check the grounding, the 12 volt switched power wire, and the relay itself. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted July 30, 2008 Share Posted July 30, 2008 If it is the FP relay and not the main power you might also check that the processor is all the way in the socket on the MS board. Also check solder joints for the processor socket if the solder job is in question. My friend had one that he didn't get the processor plugged in all the way and it had what appeared to be noise related resets until it was pushed in the socket properly. Quote Link to comment Share on other sites More sharing options...
All Z's Posted July 31, 2008 Author Share Posted July 31, 2008 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 Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted July 31, 2008 Share Posted July 31, 2008 I might be worth trying new relays. Slight possibility of a bad connection inside a relay causing it to become high resistance once it gets too hot. Quote Link to comment Share on other sites More sharing options...
SidWell Posted July 31, 2008 Share Posted July 31, 2008 It only acts up under load for the most part too. Under load, eh? That is when the injector drivers are working the hardest. The power transistors for the injectors could be heating up and failing. You might want to replace them. Do you have access to any Freeze Spray? Open the MS box locate the suspect transistors and when the unit fails, spray the suspect transistors and see if the car starts again. Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted July 31, 2008 Share Posted July 31, 2008 I have verified that both the main relay and fuel pump relay cycle on and off together. In that case, the Megasquirt's resets are symptoms of the main relay cycling off, not the cause. There is nothing inside the Megasquirt that can turn the main relay off (unlike many Bosch systems where the ECU can do this). The problem is either on the relay board or on whatever is powering it. Quote Link to comment Share on other sites More sharing options...
All Z's Posted August 1, 2008 Author Share Posted August 1, 2008 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 Quote Link to comment Share on other sites More sharing options...
SidWell Posted August 1, 2008 Share Posted August 1, 2008 Are you hooked up per the latest drawing info at http://www.megamanual.com/v22manual/mwire.htm#rb ? External Wiring with a V3.0 Main Board Because of the added stepper IAC, ignition control, and PWM idle capabilities of the MegaSquirt-II, the V3.0 main board has been designed with these functions in mind. As a result, five additional connections are made at the DB37 connector. These are shown below: Note that you should read the appropriate section of the MS-IITM EFI Controller manual for the V3 board - it contains much more wiring information that may be important for your installation: Quote Link to comment Share on other sites More sharing options...
All Z's Posted August 3, 2008 Author Share Posted August 3, 2008 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 Quote Link to comment Share on other sites More sharing options...
SidWell Posted August 4, 2008 Share Posted August 4, 2008 You can try flashing the processor firmware again. That would be the easiest thing to do. The only other option if you do not want to go romping around inside the ms is to veryify all your grounds. A bad ground can cause many different issues. Go to the latest documentation and verify your grounds on the relay board are set up exactly like the drawing shows. Quote Link to comment Share on other sites More sharing options...
evildky Posted August 7, 2008 Share Posted August 7, 2008 I think moby and matt made it clear that if the main relay is cycling off and on it's a problem independent of the megasquirt, your problem going away with the alternator unplugged further proves this, sounds like you are alternator is overcharging and overheating the relay and or the megasquirt, the electrical systems in these old cars suck, I suggest you pull all non critical fuses, I've had overcharge issues due to horn and wiper circuits Quote Link to comment Share on other sites More sharing options...
All Z's Posted August 7, 2008 Author Share Posted August 7, 2008 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 Quote Link to comment Share on other sites More sharing options...
Zmanco Posted August 7, 2008 Share Posted August 7, 2008 FWIW, the resets I experienced due to EMI from plug wires never occurred when the engine was cold although I wasn't able to isolate the conditions with the same degree of repeatability that you have. I can say that it usually occurred under hard acceleration. If you have a spare set of known-good plug wires it might be worth doing a test with them and seeing if/how the symptoms change. Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted August 7, 2008 Share Posted August 7, 2008 Take a data log and post it - this will include a record of your battery voltage and other things the Megasquirt records that will provide good clues. If your voltage wasn't steady enough to control an analog relay, it's definitely not going to be good for digital circuitry. Quote Link to comment Share on other sites More sharing options...
All Z's Posted August 7, 2008 Author Share Posted August 7, 2008 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 Quote Link to comment Share on other sites More sharing options...
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