Prior to this I have been using the megasquirt as a fuel only on my 87 TII. The car was running great before I tried to do spark control. I wired up error's board with the two condtioning circuits and connected it to the MS, as well as connected it to my CAS, and stock coils.

My biggest problem is that it doesn't want to start. I'm getting spark from the leading coils, but it's not firing at the correct time. With the crank set on the yellow mark of the pully I set the cas on the third tooth (24 wheel) past where the tooth is on the 2 wheel.

Other symptoms:
With the key on all 3 led lights are on steady. (not sure if this is normal)
The on/off idle solinoid continously cycles (this worked fine before turning on the
wheel decoder)
No trailing spark
AFR and spark advance gauges don't work in megatune (the afr gauge worked
before turning on the wheel decoder)

I 've read everything I can find on setting up the rotary with the wheel decoder and done several searches. But I still can't figure it out. I've attached my msq file and a data log of cranking. (ok for some reason it won't let me attach these). I can email them to you if you want to help.

I'm using Megatune 2.25
ms I
ms-extra 29t
stock cas and coils
error's daughter board
87 TII with 89 rotors

Thanks for any help.

JC

 

please post your msq... the bad timing is probably settings given the way you stabbed the CAS.

 

Here is my msq and the datalog in a zip file.

JC

 

Alright, I'll try to look at it today.

Ken

 

I've post some more info on the megasquirt forum if you want to take a look ken. The link is: http://www.msextra.com/viewtopic.php?p=174407#174407

Thanks
JC

 

I've been trouble shooting and chasing wires to make sure I have everything wired correctly. I found a broken wire in the trailing coil plug, so I think the I should have trailing spark now. I also found I didn't put in the 1K resistor between VR1 out and pin 6 of U4. I know I followed the directions pretty close when when I did all the modifications to the MS board so I don't think I forgot it by accident. Any reason to leave out this resistor??? It's been over a year since I soldered in the daughter board so I can't remember.

I connected the igintion system back up to the stock computer and got it running again and set the timing. Then I switched it back to the MS and after some cranking I got it to start using the wheel decoder. It started hard and ran real rough. So I know the timing isn't correct yet. I posted a datalog of it running. I am getting some rpm spikes and it is very lean (because of the timing). So am I to advance or retarded??? I'm going to play with it some more tomorrow and see if I can get it to start better and idle.

And for some reason the idle air solinoid is still cycling?????

Any insights are appreciated.

Thanks, JC

The datalogs and msq file can be found here
http://www.msextra.com/viewtopic.php?p=174818#174818

 

I'll check it out again tonight.

Ken

 

Thanks Ken.

 

I had to re-stab the cas 2 teeth counterclockwise to get the timing right but it works now. I don't understand why it works but it does. I set the fixed angle to -5 and lined the cas up to yellow mark with the timing light. then put the fixed timing back to -10.

I'm still not getting any trailing spark. I'm also getting small rpm spikes that correspond with spark angle changes. If the rpm spikes up the spark angle increase, if the rpm spikes down the spark angle decreases. I've got shielded cas wires that are grounded to grounds on the daughter board. I didn't shield the wires that trigger the coils, but I didn't think they needed to be. I have the wheel decoder routine set to 24s9 style with false trigger protection enabled. I have a good datalog that shows it but it is too big to post, but here is a link to a screen shot of it.

http://i250.photobucket.com/albums/g...g?t=1196875000

I've got some other problem (intermintent spark and afr gauge in megatune, and my fan output flickering, and the idle solinoid cycling) that leads me to believe that I may have a bad copy of the code or my main MS chip may be screwed up. I did re-flash the 29t code once, but didn't seem to help. Do you think going to the 29y4 code would help????

A review of my setup
MS1 extra 29t
error's daughter board
stock mazda rx-7 CAS and coils

Thanks for any help,
JC

 

Those RPM spikes indicate noise... how is the MS grounded?

 

The daughter board has a ground from it to the MS board. The MS board is grounded through the DB-37 to the relay board which is grounded to the chassis/body under the dash. The ground for the relay board is only a couple of feet away from the battery ground (I have the battery behing the passenger seat) which is grounded to the chassis/body. I have the shielding for the cas wires grounded to the daughter board. The cas wires are even shielded in the MS box, except for the last 1.5 inches. Should I have some other grounds??? I tried adjusting the cas signal adjusting resistors on the daughter board but that didn't have much of an effect.

JC

 

how many ground wires go from the MS to the relay board, and from there to the chassis? Usually in my experience with VR sensors, it's a bad idea to ground the computer to the chassis. You want to ground it to the engine, or to the battery. I know of some people who have had problems grounding to the battery.

Also, you should have at least 3 or 4 ground wires from the MS to the relay, and from there to whatever ground you choose.

Most likely the signal problem could also be cleaned up by adding a .01 uF cap across the G+ and G- inputs into the daughtercard. I had to do this to get a good RPM signal on my car.

Finally, when you hit the brakes or do other things that increase electrical load, do the temperature gauges or TPS fluctuate at the same time?

Ken

 

OK, the reason you had to change the CAS stab was that you're using wheel decoder settings of 1,3,7,9... With those settings, the CAS should be stabbed with the Ne sensor on the third tooth after the G tooth.

If you want to use the stock CAS stab, you need settings of 11,1,5,7. For the stock stab, you'll also want the trigger angle at 65, not 60.

Cranking timing using the stock settings seems to work better for me with time-based, and between -5 and 0 deg.

With the settings you have, cranking timing of 0 and trigger return should work fine.

Ken

 

Ken, thanks for the reply. I'll double check the grounds between the MS and relay board but I think I have at least 3 or 4. I'll also try grounding the relay board to either the engine or battery. If that doesn't work I'll try the capacitor. I also see if I get any changes with brake lights and/or headlights. I'll be out of town till mid next week so I'll check then.

Thanks again for all the help.

JC