custom13B

Well Im hoping someone had a simular problem and can give some tips with this one. Heres the rundown on what I have and have done. I built and tested a V3 megasquirt using a MS stimulator. I read all the FAQ and followed the directions and performed the mods. I installed the 3- 4.7k pullup resistors and verified they came from a 5 volt source and went to the correct lead on the LED's. I wired the CAS and coil packs according to the FAQ I double checked it as well. I installed the jumpers on the MS board for the VR curcuit VRin to tach select and VR out jumper etc etc. I programmed megatune exactly like in the FAQ and double checked that as well. The basic problem is I get no spark. No leading or trailing spark. I have errors daughter card wired in for trailing spark as well. At this point I am not tooo concerned with trailing..just getting leading to work would be nice. When I hook up my lap top the MAP guage responds with vacuume when cranking engine and the TPS guage moves as I move the throttle...the RPM guage however does not move when cranking the engine. Im wondering if theres a feature I need to turn on or a jumper I missed? I have coil packs and a CAS from a good running engine so I know the problem dosnt lie there. I also know I have a good strong running engine from before this MS conversion. I performed Ohm tests on the sparkplug wires and they test fine and also installed new spark plugs. I am testing for spark with a snap on spark tester. I am positive there is no sparky. Any tips would be much appreciated. Thanks you

muythaibxr

first off, you need vroutinv to tsel... or you won't get an accurate trigger....

also, did you adjust the potentiometers on your v3 board all the way counterclockwise?

Also, you have to choose a good ground for the megasquirt, if you don't, you can get interference causing you not to get a tach signal.

If you're not getting a tach signal you won't get spark. So fix the tach signal problem, and see if you get spark after that.

custom13B

Thanks...wow that was fast. I definately have a good ground I made sure of that. However One jumper is wrong and not inverted could be most of the problem right there. I did adjust the pots. I understand about the tach problem hopefully when I correct the jumper I get a tach signal. Thanks again Muy.

custom13B

Well major thanks to Muy! It now runs! Leading only ignition but Im not complaining. I have Error's daughter card but have a stoopid question. Im just using it for trailing for now. On the wiring directions it says T1 goes to the CAS goes to the 2 pin wheel T5#1 ground with load resistor. and T3 conditioned output goes to pin 6 of U4on the MS board. My question is this....can I wire this to pin 11 of U1 with the load resistor of course since this is my trailing ckt? Or do I still need it to go to U4? Next stoopid question...does T5 go back to the CAS with a inline resistor? May sound dumb but just want to get it right. Many thanks to everyone on this forum for your help and time,Shawn

muythaibxr

The output of the conditioning circuit for the 2 tooth wheel should go through a 1k resistor to pin 11 on U1.

The output of the conditioning circuit for the 24 tooth wheel should go to u4 pin 6.

If you've got it running now then it should be wired right, so if you're not getting trailing, either the wiring between your ignitor and the MS is messed up, or you don't have it set up in software.

custom13B

Ok I understand about the output from the 2 tooth wheel going to pin 11. Im using a V3 board so I assume I dont need to be concerned with pin 6 of U4 at all? I already have a wire soldered to pin 11 of U1 with a inline resistor of the right value. Im basically confused about the wiring of the daughtercard. So right now Im only sure on 2 things. T1 goes to the 2 tooth wheel on the CAS I got that part. T3 is the conditioned output of the VR circuit that would go to pin 11 on U1 I got that. But the wiring directions say T5 goes to ground with a load resistor,,thats where Im lost. I would think T5 would need to go back to the CAS? nd T5 needing a load resistor is also confusing me. Any tips would be great,thanks once again.

muythaibxr

I don't remember the designations that were used for that board (the T1, T5, etc... that you keep talking about). ... but if you're using a v3 board, you don't enven really need a second vr sensor conditioner, as it already has one built in.

Since you said you were getting a tach signal and the car was running, the CAS wiring you have set up is correct.... If that wasn't set up right, you wouldn't be able to even have rpms displayed in megatune, and the engine wouldn't run.... If trailing isn't working, it's like I said before: your wiring or your software setup are incorrect (or your trailing ignitor/coils have a problem).