Zmanco Posted May 28, 2007 Share Posted May 28, 2007 I'm installing MS1 v3.0 with MSnS fuel-only on my N/A L28. I suspect I am not getting any fuel dispensed by the injectors. I've confirmed I have spark and fuel pressure to the rail. If I pull the plugs after cranking, there is absolutely no smell of gasoline. Now and then if the engine has sat for a few minutes, when I first crank it, it acts like it just might start, but that only lasts for about 1 second and then it's back to the usual crank and no start. Another clue: none of the 3 LEDs on the MS box ever light. I've confirmed that the flat side is towards the DB9 connector. I have the 6 injectors split into 2 banks and neither appears to be firing, or at least not enough. I thought maybe there is an issue with the FET on the main board, but it seems unlikely both are bad. I've check my soldering for bridges and cold joints and all looks good there. All the sensors show normal readings in Megatune. I've attached a few screenshots showing the cranking settings. I've experimented with changing the pulse widths on the cranking table, but that doesn't seem to make any difference. I also tried connecting my DVM to one of the injectors wires to see if I could measure any voltage while cranking, but I'm not getting anything. Unfortunately I don't have access to a scope. At this point I'm pretty tired and keep thinking there must be something simple I'm missing. Suggestions? Quote Link to comment Share on other sites More sharing options...
bryan01 Posted May 28, 2007 Share Posted May 28, 2007 did you test it out on a stim board? if so did it work on that? have you checked your RPM signal? i had a problem w/ that when i started, see my posts below. w/o a good rpm signal it wont squirt fuel. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted May 28, 2007 Author Share Posted May 28, 2007 I don't have a stim board and was hoping to not need to buy one. Just hate to buy it and use it once. But that may my next step. How would you check the tach signal? I am running off the negative side of the coil. I did temporarily route some shielded line to see if there was maybe interference, but it didn't make any difference. Quote Link to comment Share on other sites More sharing options...
bryan01 Posted May 29, 2007 Share Posted May 29, 2007 i'd get a stim board to test it out first. and if you have a single coil setup it's a lot easier for you to get a tach signal than i. i had to make a circuit to read 6 coils ... but yeah, it sounds like you have it hooked up correctly as far as that goes. i'd test the megasquirt and go from there. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted May 29, 2007 Author Share Posted May 29, 2007 Update: I went back out in the garage, and with the dimmer light, I can see the injector LED flash twice when I turn the ignition on, just as it should. I heard the injectors firing twice too. I also found out that if turn the ignition on, wait for it prime the injectors and let them fire, then turn it off, and then repeat a few times, that when I try to crank, it almost starts. I don't think I have any hardware issues - I think I must have some setting incorrect. I'm attaching the msq file. Anyone with MS experince mind taking a look through it and see what might be causing me to not have enough fuel be injected? I feel like I am so close!!! megasquirt200705281127.zip Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted May 29, 2007 Share Posted May 29, 2007 Yes you are probably getting the Priming Pulse when you turn the key but the ECU is not getting a timing signal to keep firing. A stim board would really help you narrow it down here. Is your TPS calibrated and wired correctly? You might be invoking flood clear mode. "The 12 volt supply for MegaSquirt MUST supply power in both the RUN and CRANK positions" double check this. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted May 29, 2007 Author Share Posted May 29, 2007 I think you are correct, I think there is a problem with tach input circuit. That is the only thing so far that explains everything. I've confirmed I have continuity from the negative side of the coil to the tachselect jumper on the main board, so I'm pretty sure my wiring is ok. Power to the MS is solid - I used Megatune to monitor the battery voltage during cranking and it stays above 10v. I've got the board out of the car and have gone over the assy instructions and can't find any mistakes yet. I followed instructions 50b and 52 for the Hall sensor. For those of you still with me, does that seem right for triggering off the coil? Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted May 29, 2007 Share Posted May 29, 2007 You'll need to follow the specific instructions for triggering off the negative terminal of the coil, including using the reversed Zener diode. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted May 30, 2007 Author Share Posted May 30, 2007 After further email with Matt, turns out it's not possible to use the Hall input off the negative coil with an MSD. I guess I should have realized because: a) the coil is floating (electrically) with the MSD box (neither side is referenced to ground) with its multiple sparks at lower rpms it wouldn't have worked anyway. I changed the board for a points trigger and connected to the MSD's tach output and she runs! Now I need to tune. Wow, glad that part is behind me PS. Nowhere in the MS documentation is this covered. Is there some place on this site where we can list this sort of thing? I'd hate for someone else to have to go through this. Quote Link to comment Share on other sites More sharing options...
bryan01 Posted May 30, 2007 Share Posted May 30, 2007 yeah my tach signal problem was the same way, it took several sleepless nights to find a solution, and it was hard b/c i didnt know what i was looking for until i found it. just post a good write up and maybe it'll be stickified congrats on getting it running Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted May 30, 2007 Share Posted May 30, 2007 Daniel congrats on fixing the problem yes you can post your findings on MSefi.com which is the megasquirt forum Quote Link to comment Share on other sites More sharing options...
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