Megasquirt timing issue

[Edub1]

MSII board 3.75 version 2.68

1989 Nissan 240sx KA24E - stock dizzy

Seems like as soon as the skip pulses are done and I get my first spark it comes way early and stops the motor from even cranking. I tried adjusting the offset from -15 to 180 and several points in between with ne luck. I increased the skip pulses to 10 and it cranked until that first spark. I also lowered my table to some low numbers with no luck. What could be causing this?

[480sx]

Dude, this was the exact same issue i had that crushed my MS2 experience(and my starter..). I was thinking it was because i had my dizzy rotated as far advanced as it could be in the TDC position, but i never had time to test my theory. I tried everything i could think of to fix it. I tried using the cold advance table to retard timing when the engine was cold, a crap load, still, barely any change. I tried pulling timing from the timing map at start up pressures. I had the timing map turned down to like 4(100kpA), 4(95), 5(90), 7(85), 10(80), ect ect. Something close to that at least, but you get the idea. That would cure the problem, but only on hot starts. On cold starts, no mater what i did, i couldnt get the fking thing to stop doing that.

I didnt post about it because i was thinking it was just a dumb *** mistake of having the dizzy all the way advanced, and no one else would have that problem.

Do me a favor, try rotating your dizzy all the way to the furthest point towards you, when your in front of your engine bay. In another way of saying, rotate the dizzy as far as you can to the left, as your looking at it from the driver side fender. Then, recalibrate using the trigger wizard to deal with the change.

Damn that makes me feel like **** i should have posted that i had that issue, so you guys would have been atleast warned.

EDIT - First however, you need to get your offset dialed in. Have you used the trigger offset wizard? Its really easy to do, make sure you have done this. Start at 72, get the car running, and use the wizard to do the rest.

Oh, and the stock starter is pretty resilient to that kind of abuse, it took me over three months of......... Reeearr reearrr clunk... you get the idea.. befor it finaly took a dump.

[Edub1]

Wow, so it's not just me. My dizzy should be stock +15. I could try messing with it but I hate to change more than 1 thing at a time.

I'll try it at 72 and I didn't think about the cold advance. Plus, I need to calibrate my coolant temp sensor.

In the end what was it that solved the problem?

[Edub1]

I tried setting the trigger to 72, checked the cold advance and collant temp sensor. I also set my advance map values to -10 with no luck.

WTF is going on here? Should I try rotating the dizzy before getting it running? I hate introduce a new variable.

[neverlift]

mark dizzy with sharpie then adjust one way or the other. try it try the other way too if it doesnt help then adjust back to mark

the dizzy stuff they couldnt explain is why I passed on the m/s

[480sx]

Haha, what solved the problem eh? The VB fried itself when i left my ignition on overnight, fixed my problem right up. Now my MS unit is sitting in a box in my shop lmao, and i got an Enthalpy. Mmmm sure is nice to have a running car! Lol ill stop.

I mean if i had fixed it, i would tell you what i did to fix it, but, like i said it was one of the main reasons i put MS2 on the back burner. I plan on picking it back up this winter, i have a new, front wrecked s14 to play with. Maybe by then we can work this issue out, would be nice....

No, dont rotate the dizzy until you have it running. Get your car idling, im assuming you have it to where it idles well by now? Then, loosen your dizzy bolts and rotate it just enough to start hearing a difference. When you do, use the trigger offset wizard in Megatune and recalibrate your Trigger offset to deal with the new dizzy position. You know how to use the trigger offset wizard right? Have you used it yet?

Basically, just keep doing that till you have the dizzy rotated all the way twords the front of the engine bay. Thats my theory of how to fix it... I tried everything else i can think of. Also, remember to use the Ignition table to pull timing from the start up bins. With those, i was able to get it to stop doing that on hot starts.

If it hadn't of fried my starter and the VB itself i was going to drive down to GA and get the guys from DIY Autotune to figure it out, i was at my end with the damn thing. Worse comes to worst ill do that sometime this winter if we cant figure it out by then. The bad news, is your stuck with a hacked up wiring harness and a car thats embarrassing to start.. Unless we can figure the beast out. Ill try to help as much as i can, just stay calm and patient with it.

[neverlift]

lol patient edub pppppphhhhhhhhhhssssssssst why you think he is on m/s? I'm playing dub.

check out the ka forum IIRC a couple guys are running the ms on n/a ka's I think a write up even exists for the install and basic setup, not sure what all its been too long... just search on nicoI'll see if I can find it later today since its rainly like a fat chick drips drops of sweat while eating. sorry had to say it its a noreaster=ghey

[neverlift]

kat my bad zerothread?id=221623

[krazydriver]

edub i'm in the process of actually building my MS2, although i am planning on running the ms2 extra code.

i know you want the distributor clocked to full advance, and i read somewhere on the megasquirt forums that 78 degrees is a good starting point for the trigger offset.

you are getting the proper tach readout for cranking right? you may have some noise on the tach input circuit that's messing things up.

either way hope you figure this out, cuz in about a week i'm gonna be in the same boat.

[krazydriver]

think i may have found the problem.

the simple false trigger prevention method will not allow my engine to start. It just kicked back and would never quite catch. I put my poor starter through a beating!

I ended up configuring the Advanced false trigger prevention time mask setting to 10-30%. The defualt 50% time mask would also not allow my engine to start.

Jsmcortina wrote "I need to look into this - the "simple" mode was supposed to be a copy of the built-in settings on all MS1 variants, that seems to work for everyone. I must have made an error somewhere."

There is some info on Advanced trigger options. simple mode does not allow my Nissan CAS equipped vehicle to start. I do believe others had problems with simple mode aswell.

Only MS2 has the false trigger setting so that would explain why people aren't running into it with ms1. that and megatune defaults the false trigger to simple. Try this out and let us know if it works!! if that's the solution i should be all set to install my MS2 next weekend.

[480sx]

Damn i played with that setting too but i couldnt get any results out of it. That sounds like it would fix it, dude your the man!

I cant wait till we get some feedback on this, it feels like thats the fix. I cant believe theres nothing in the MS2 tuning section of the mega manual.. Wow that gives me hope for MS. Good work!

[Edub1]

Ok, got a reply on the MS board. The guy says that the trigger offset is ignored unless I select calculated trigger. I don't understand how the motor would ever start without that info. I've asked and await his responce.

http://msefi.com/viewtopic.php?t=28633&highlight=

[480sx]

Dude your supposed to have your ignition set to falling edge, not rise... Is that guy just making an assumption or do you really have it set to rising?

Did you try fixing it with the above advice, crazy's?

[krazydriver]

480sx,Grippo checked the MSQ he posted. I opened it up and input trigger is set to falling edge like it's supposed to. The cranking trigger is set to trigger rise.

Under the ignition options though, the next pulse tolerance is set to 50%. Basically this is the same setting as the false trigger for MS2 extra, as i mentioned in my previous post. Just because of the fact that the symptoms of the false trigger seem to match what your having i would at least try to start it up with that setting lowered to maybe 15% or so.

[480sx]

Ah right, i was to lazy to check his MSQ, and just skimmed over the post. My real question for Edub though is if he's tried messing with the pulse tolerance's.

[Edub1]

I haven't messed with them too much. I think I set them to 10. Playing with the dizzy allowed it to crank and even sputter a bit. I'll be playing a bit more soon.