OhBilly Posted November 14, 2012 Share Posted November 14, 2012 I've already posted the following on MSEFI, but thought I'd give it a shot here as well: Running MS1 V3.0 with Extra 029y3 code. Installed on a Datsun 240Z with an L28ET, with the following relevant setup info: * Using Megasquirt Relay Board * Innovate LC-1 getting power from the +12V switched terminal on the Megasquirt relay board * LC-1 is wired to a relay so it cuts power to it during cranking * All sensors (except CLT), injectors and the Megasquirt board are all grounded to the same location on the engine block * Using stock single wire coolant sensor * Low impedance injectors utilizing PWM on the MS board Car runs very well once I get it started, but getting it started is next to impossible. It starts easier when it is warm out, but it is still difficult. I'm getting resets during the transition from cranking to running, and I suspect it is due to the way I have wired up my LC-1. If you look at the datalog, you'll see that during cranking the O2 sensor voltage goes to zero (like it should because of the relay), then when the engine fires and I release the ignition key to running position, I get a spike in the O2 sensor voltage and battery voltage, followed by an ECU reset. You'll also notice a corresponding spike in the coolant temperature. Now I don't really know which is happening first, the resets or the spikes. In most cases it looks like the spikes happen, followed by the resets, but a few of them are reversed. My theory is that when I release the key from cranking, the LC-1 is immediately switching on and creating noise that is causing the ECU to reset, but I'd like some expert opinions before I make any changes. I plan to try to start the car without the LC-1 hooked up and see if I get the same result, but I haven't tried it yet. Hoping someone can chime in first. MSQ and datalog are attached. Thanks for the help. Bill rustbucket_11-14-12.zip Quote Link to comment Share on other sites More sharing options...
BLOZ UP Posted November 14, 2012 Share Posted November 14, 2012 I would try with the LC-1 disconnected first.... I have the same issue, not related to my LC-1, I think. It's more of a trigger noise issue AFAIK. But I haven't seen my car in months, so maybe I'm remembering wrong. Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted November 15, 2012 Share Posted November 15, 2012 Also, be sure the ignition key doesn't cut off power when moving from Start to Run. Had that issue crop up on my Dodge Dart. Quote Link to comment Share on other sites More sharing options...
rossman Posted November 15, 2012 Share Posted November 15, 2012 Also, be sure the ignition key doesn't cut off power when moving from Start to Run. Had that issue crop up on my Dodge Dart. Exactly. I believe all 240/260 ignition switches have separate electrical contact pads for cranking and running. There is a momentary cut in power when the ignition switch translates over the pads. I installed a 280 ignition to solve the issue. Quote Link to comment Share on other sites More sharing options...
OhBilly Posted November 15, 2012 Author Share Posted November 15, 2012 I tested it last night, and the ignition switch isn't causing the problem. I disconnected the starter solenoid and datalogged multiple "fake" starts, turning the key back and forth between Start and Run and it never caused a reset. At this point it looks like the starter solenoid is causing the problem when power gets cut to it going from Start to Run. Someone on msextra.com suggested the hold-in coil is causing the problem and advises to install a diode from the start terminal to ground. Does this sound like a good plan? Thanks. Quote Link to comment Share on other sites More sharing options...
motomanmike Posted November 16, 2012 Share Posted November 16, 2012 (edited) If this is a new issue and you've narrowed it down to a starter why wouldn't you just replace the starter? Also many solenoid issues stem from weak batteries arcing the contacts which can cause electrical noise especially during the release of it. Get the battery tested, sounds basic but I see $$$ thrown away daily from people trying to get cars running on weak batteries. If at fully charged it can't hold 10v with a 300 amp load I'd replace it. Weak batteries eat starters and also cause very odd issues especially with relays. Makes them stick, or hang longer than they should mostly. Using a relay board and a relay on the LC-1 you've got relays between every signal the ECU is looking for. Just a thought. Edited November 16, 2012 by motomanmike Quote Link to comment Share on other sites More sharing options...
OhBilly Posted November 16, 2012 Author Share Posted November 16, 2012 I did some more testing with it last night and it doesn't look like the resets are being caused by feedback from the starter solenoid. I installed a relay on the starter circuit and I still got the same effect: reset during transition from cranking to running. But I also noticed something else: if I crank it just momentarily, not giving it enough time to attempt to start, I do not get a reset. I only get a reset when the RPMs get above my cranking threshold, which is set at 300 RPM in my case. I am using Supra 440cc low impedance injectors and driving them utilizing PWM on the MS board. Perhaps something is goofy with the injector flyback circuit, but keep in mind that if I can actually get it to start, it runs very good with no resets. Also, when I do happen to get it started and let it warm up, if I shut it down it will restart again without difficulty. Could it be that my cold cranking PWs are so off that it's just not getting a good clean "kick" to get it going, and the subsequent engine stumbling is causing the resets? Could it be that the starter is not disengaging cleanly when it tries to start, and that's causing something to go amiss? Mike, the issue isn't really new, at least I don't think. I just got the soldering on the board fixed up a few months ago (shorted transistors), and I've only had the car started a few times since then. The first time I got it started the outside temp was about 65 degrees, but it took me a long time to get it going. I got it started again last week but it was also on a warmer day, about 60 or so. But each time I've got it started and warmed up, it restarted easily after turning it off. Last week I ran the car, warmed it up and turned it off. Three hours later I went out and bang, the car fired right up. Also, the battery is new but I have had to recharge it multiple times due to many failed start attempts. Attached are screenshots of my constants, cranking, after start and warm up tables. If anybody sees anything suspect here, let me know. Any ideas would be very helpful. Thanks. Quote Link to comment Share on other sites More sharing options...
motomanmike Posted November 16, 2012 Share Posted November 16, 2012 What distributor and coil set up are you using? Quote Link to comment Share on other sites More sharing options...
OhBilly Posted November 16, 2012 Author Share Posted November 16, 2012 What distributor and coil set up are you using? 83 ZXT distributor and coil, running it in MSnS mode. Quote Link to comment Share on other sites More sharing options...
OhBilly Posted November 19, 2012 Author Share Posted November 19, 2012 Another update: I've reflashed the firmware in the hopes of that solving something but didn't have any luck. Spent about 5 minutes cranking on it and got over 100 resets during that time. Resets almost always correspond to when the RPMs get above my cranking threshold. Even if I hold the ignition in the "start" position when it tries to start, I still get a reset so I'm sure it isn't due to the starter. What happens inside of MS when it transitions from cranking mode to running mode? Since I'm running PWM on my low impedance injectors, could it have something to do with the flyback circuit? Getting very frustrated... Quote Link to comment Share on other sites More sharing options...
NewZed Posted November 19, 2012 Share Posted November 19, 2012 (edited) Could just be electrical noise causing resets. Check the shielding on the shielded wires that go to the ECU. Make sure the shielding is grounded correctly, you might have a ground loop setup. Most shielding should only be grounded on one side. Move the lines away from any wires connected to the coil or spark plugs. A voltage spike can be induced in a wire just by being close to another wire with high voltage. Stuff like that. Pretty sure it's described in the Megamanual somewhere. Edited November 19, 2012 by NewZed Quote Link to comment Share on other sites More sharing options...
motomanmike Posted November 19, 2012 Share Posted November 19, 2012 (edited) Your pulsewidths and dwell would change quite drastically from cranking to run, maybe getting some feedback during that transition with the coil? One way you could narrow it down is to pull the fuses for the injectors, crank and see if you get resets. Install the fuses back and pull the coil trigger wire and crank and see if you notice any changes. Do you have a stim? Edited November 19, 2012 by motomanmike Quote Link to comment Share on other sites More sharing options...
OhBilly Posted November 19, 2012 Author Share Posted November 19, 2012 I've cranked it with the fuel pump fuse pulled and I did get resets because it tried to start on residual fuel in the cylinder. I haven't tried pulling the injector fuses yet but will definitely do so and try it out. Regarding the coil, one thing I have done recently is hook my stock current sensing tach back up. Right now I have the stock black/white wire that comes from the stock tach feeding the positive side of the coil, rather than feeding power to the coil directly from Megasquirt via the fuel pump output on the relay board. Although the car is almost impossible to start, when it does start it seems to run just fine after that. Perhaps I should change this back to the way it was. Another thing I just realized this morning is that I could have created some bad grounding issues. When I had the car starting halfway reliably, I just had the MS box sitting on the passenger seat. Now it is attached to the transmission tunnel in the passenger compartment with screws going into the sheetmetal there. This is grounding the case, very poorly, through this attachment and likely creating a ground loop. I'm sure this isn't good so will try fixing this first and see what happens. Thanks for the help. Quote Link to comment Share on other sites More sharing options...
motomanmike Posted November 19, 2012 Share Posted November 19, 2012 Did the car start ok before you wired up the tach and coil the way it is now? Quote Link to comment Share on other sites More sharing options...
OhBilly Posted November 19, 2012 Author Share Posted November 19, 2012 Unfortunately Mike, I don't really have enough data to tell. Here's the history of it best I can remember: * Summer time, nice and warm. Stock tach not hooked up. Positive side of coil fed from fuel pump output on the MS relay board. MS box sitting on the seat of the car. LC-1 not installed. First start attempt, got it running and idling without much trouble but only one bank of injectors were firing, so the car was running horribly on three cylinders. I didn't datalog a start, but I did datalog once I got it running... no resets. Didn't notice any resets on cranking, but I wasn't really looking for them. * Pulled the MS board out and found bad solders (shorts) on a few of the tiny transistors that are part of the injector driver circuit. Pulled the resistors, cleaned up the excess solder and put them back on. * September, outside temp about 60 degrees. Everything still hooked up the same as before. Still no LC-1. Took a while to get it started by messing with the cranking pulsewidths and after start enrichment. Once it started the engine ran nice and smooth. Took it out for a drive around the neighborhood and it ran good. Parked it back in the garage, shut it off and started it back up to make sure it would restart (started right away, no stumbles). Didn't datalog a start, but did datalog while running. No resets during running, and didn't notice any during cranking but again, I wasn't looking for them. * Hooked stock tach and coil up the way it is now. Mounted MS box the way it is now. Wired in the LC-1 but didn't hook up power to it. * October, temp in the 50s. Tried like hell to start it but it wouldn't go. Best I could get was a few seconds of running. Fuel pump was randomly turning on and off and the readout in Megatune was very erratic. Didn't datalog anything. Turned out I messed up my grounds when wiring in the LC-1, so I pulled the grounds and cleaned them up real nice and reinstalled everything. LC-1 still wired in, but no power going to it yet. Didn't attempt to start it yet, but verified the strange fuel pump behavior and erratic readings in Megatune were fixed. * Late October, temp in the 50s. Spent about 5 minutes cranking on it until it finally fired up. Didn't drive it but I let it completely warm up. Idled nice and smooth. Didn't even start up the laptop so I didn't notice or suspect anything was wrong, but I did have a really hard time getting it to go. * Early November, temp in the 50s. Finished hooking up the LC-1 and calibrated it. Spent a bunch of time getting the car started, but she finally fired up and idled nice. During my start attempts, I notice the CLT and TPS readouts jumping wildly when it would try to start, and noticed the red flashing in the lower right corner of the Megatune screen indicating resets. But no resets after it got started up and idling. No datalogs. LC-1 was working and reading about 12.5 AFR at idle. Turned off the car and let it sit for about 3 hours. Went out to start it and it fired right up without any stumbling and idled very nice. And here we are now, with several days behind me trying to get it started. Had temps in the 50s yesterday and I tried to start it without any luck. Got it to try to run but my best was about 3 or 4 seconds. When the car tries to run, it throws resets like crazy. But it's very rare that I get a reset during cranking, I'd say 95% of them occur when it tries to start and I let off the key. The LC-1 is disconnected, and it doesn't seem to make any difference in the number of resets I see. I plan to try it again with the MS box lying on the seat like before, and eliminate the potential ground loop I caused by mounting the case to the transmission tunnel. If it still gives me fits, I'll eliminate my stock tach and wire the coil as I had it before. Thanks for the help. Quote Link to comment Share on other sites More sharing options...
motomanmike Posted November 19, 2012 Share Posted November 19, 2012 (edited) Sounds like a good plan to start. Just curious, have you tried starting the car jumping the starter solenoid to get it to crank to rule out totally that roll back of the key under load? I know you said you check for resets with the key switch wire off the starter and didn't experience a reset but the key may act funny with the 3-7 amps a solenoid will draw from the switch wire. Just another easy to try thought. Edited November 19, 2012 by motomanmike Quote Link to comment Share on other sites More sharing options...
OhBilly Posted November 19, 2012 Author Share Posted November 19, 2012 Sounds like a good plan to start. Just curious, have you tried starting the car jumping the starter solenoid to get it to crank to rule out totally that roll back of the key under load? I know you said you check for resets with the key switch wire off the starter and didn't experience a reset but the key may act funny with the 3-7 amps a solenoid will draw from the switch wire. Just another easy to try thought. Nope, haven't tried that but it's a great idea! I have a remote starter thingy so it will be easy to try out. Quote Link to comment Share on other sites More sharing options...
OhBilly Posted November 21, 2012 Author Share Posted November 21, 2012 Some success. Un-grounded the case and I got it to fire up fairly quickly. Far less resets but at least it was running. RPMs would surge, then I'd get a reset, it would stumble and repeat over and over. So, I disconnected the stock tach and fed the coil via the fuel pump output on the MS relay board and tried it out... she fired right up, idled nice with no resets. For now I'll call the problem solved. Hopefully you don't hear back from me for the same problem in a few days. Thanks for all of your help. Quote Link to comment Share on other sites More sharing options...
motomanmike Posted November 21, 2012 Share Posted November 21, 2012 Thats really cool. I'm glad you got it half way narrowed down. I would dare say you'd be ok mounting it back it really sounds as if the issue was in the coil wiring. Two of us on the same day back running today. I had a fuel issue I got straight today and FINALLY got to drive my car. It still has a very rough tune but man it runs and pulls in boost with low AFR's so i'll gradually lean it out. Good luck with the rest of the project. Quote Link to comment Share on other sites More sharing options...
FricFrac Posted November 22, 2012 Share Posted November 22, 2012 Sounds like grounding and noise issues - possibly ground loops. What is your grounding setup? Quote Link to comment Share on other sites More sharing options...
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