losing rpm signal above 100 rpm

[thephoneguy]

this is what i've got

edis setup with jimstim v 1.4
1994 jdm subaru 2.0 ltr EJ20HDXAJE 160 hp N/A(if all goes well I will turbo it to 325 hp)
EDIS 4/36-1/ 305 cc/min injectors Msns 3.0, LC-1, Boost Controller, Fan Control, megatune v2.25, 029y4

you can see the input from the stimm in green on the scope pics and the output from the optoisolator in yellow right above it.

as soon as i put on some rpm the signal from the stimm gets nice and square and then i lose rpm signal at about 80 rpm.

this is mega at 50 rpm
8
this is the scope at 50 rpm notice that the green is the tach signal from the stimm and the yellow above is output from optoisolator notice that the green signal is at 5.67 volts and that the opto isolator signal in yellow above is at 1 volt


this is mega at 3000 rpm

and this is the scope at 3000 see the nice square wave from the stimm but nothing coming out from the opto isolator.
I think i may be losing the threshold unlike the lower rpm where the signal was all over the place.



i wish the scope pics were more clear. I will work on that later and maybe resubmit.

any idea would be appreciated.

[Matt Cramer]

If you're using an EDIS module, you shouldn't jumper the JimStim for missing teeth. Also, how is the output jumper itself set up? Do you have a 12 volt pull up enabled?

[thephoneguy]

If you're using an EDIS module, you shouldn't jumper the JimStim for missing teeth. Also, how is the output jumper itself set up? Do you have a 12 volt pull up enabled?

ok Jim stim is now not jumpered for missing teeth.

output jumper is setup with 12volt pull up(from jimstim)

still no injector signal or rpm signal but if i put a 2k to 68k resistor between ground and XG1 I get a beautiful signal for the injectors and the rpm works very well....

so.... unless that resistor is there i get no signal out from the opto-isolator to r13 or opto-out.

I don't know why this is so.