EDIS LED17 SAW Flakey Spark???????

superchargingmachine · Thu Jul 20, 2006 5:18 am

Last weekend I finished the install of my daugheter board. I also moved my EDIS spark output from Fidle to LED17 so that I could use PWM idle.

Now I am having what I believe to be a spark problem. In as I approach 4000RPM the car starts to feel rough or stutter. I have pushed it to 6000RPM but it never gets better.

Is there anything I could have done wrong with the LED17 circuit to cause a flakey SAW? I will put the timing light on it in the driveway tonight and see if I have a stable spark advance at 4000 and above. I suspect either unstable spark advance or weak spark.

Megatune is showing the correct spark advance and at low speed with the timing light I am getting spark advance if I blip the throttle.

Post by **jsmcortina** » Thu Jul 20, 2006 5:26 am

Strange. You did fit the 1k pullup for the output?

Try disconnecting the SAW and seeing how it goes (it will be lame due to low advance though)

James

superchargingmachine · Thu Jul 20, 2006 5:33 am

I had to go look to be sure about the 1k. My 1K is between D17 and the CPU side R25. I will fix it tonight.

It occred to me to unhook the SAW as I hit the send button. I will also try this just to confirm that it is a SAW problem.

Post by **jsmcortina** » Thu Jul 20, 2006 6:53 am

superchargingmachine wrote:I had to go look to be sure about the 1k. My 1K is between D17 and the CPU side R25. I will fix it tonight.

If I'm reading this correctly then you will get very strange behaviour as the output will be messed up with the CPU and transistor "fighting" each other.

James

superchargingmachine · Thu Jul 20, 2006 7:45 am

I think I am having messed up behaviour.

See the picture should I be on the "Top" or "Bottom" of R3?

Post by **jsmcortina** » Thu Jul 20, 2006 8:50 am

Did you read the following in the instructions?
http://megasquirt.sourceforge.net/extra ... dware.html

(v2.2 board)
1b) If using LED17 output:
. Solder 1k resistor between the (-)leg of D17 and the right hand end of R23 (+5v). Run a length of wire from the (-) leg over to X11.
. Connect DB37 pin 25 (X11) to SAW on the EDIS module **It can be very useful to install a plug and socket in this line**

R3 and R25 have nothing to do with it.

James

superchargingmachine · Thu Jul 20, 2006 9:12 am

Yep, I'm a dumb ass. In a hurry as usual. Thats likely how I made the R25 mistake in the first place. I just glanced at the board and thought R3 was R23 then never even paid close attention while I was making the pretty picture.

I see now that R23 is between D17 and D18. I will use my meter and find the 5V side.

superchargingmachine · Thu Jul 20, 2006 4:12 pm

James, Thanks! Getting D17 and R23 properly connected fixed the problem.