no rpm reading with Jimstim
 

I've nearly completed the build of my MS2E for a '00 with stock sensors.
All is working fine except that I can't get an rpm reading with the jimstim.
I'm using Abe's input circuits (on pin 24 and 25)

On the Jimstim, everything looks ok:
- dips are set for miata: 2,3,6 are on, others are off
- connected a jumper from 2nd trigger to pin 25 (IAC1A)
- primary tach jumper is in the bottom location, no other jumpers next to it

Basically like this:

http://img33.picoodle.com/img/img33/...mm_717efd5.gif


On the MS I wired the 2nd trigger input to be fed from the IAC1A terminal (pin 25 of the DB37). I have continuity between Jimstim 2nd trigger pin and the input of Abe's circuit.

I can only assume this must be a software setting ?
I selected miata 99-00, falling edge, spark output going low, wasted spark, D14.
Anything else I need to set?

When I select EDIS, I do get a reading so I assume that my primary input is ok (CKP) but that my 2nd input (CMP) must has a problem.

I still haven't figured out if I need to do the CMP and CKP input mods on diy as these instructions are for a 90-97. I'm using Abe's input circuits.

Anyone?

Abe's circuit is a substitute for the DIY circuit. One or the other, not both.

It does sound like a hardware problem. Possibly something trivial like a pullup. Eyeball the circuit, dude. That's all we can tell you.

I thought only dips 2 & 3 should be on. or is that 90-97 only.

I checked the circuits and I really think they are ok. I measure the same values on every point of both inputs circuits.
I didn't build the diy circuits, just Abe's.
With dip 6 off, I get some rpm reading. I can set the rpm with the pot and I get a corresponding rpm value in megaview, but the reading constantly drops to zero and back. Doesn't seem right.

Might wanna check the PROM rev on your JimStim. Switches 2,3,6 on is the correct setting for '99-'05 Miata, but this was only added in the latest (2.0 firmware.

I have 2 white dots, so this should be the correct firmware. Starting to think this is a JimStim problem, not a MS problem.
I'll try using the 2nd input circuit in edis mode, to make sure it's functional.

Hi Frank,

Jimstim settings are just like mine - I also run Abe's circuit.
It should be working this way.

So maybe it really is a hardware problem...

I found that the 2nd trigger output from the JimStim isn't working as it should.
Contacted Matt about this and apparently, some early JimStims had a problem with the Miata mode. I think I have one of them. Waiting for more info on this.

Edit:
Matt confirmed that the wheel pattern for the '99-up Miata was changed between the two-dot and three-dot versions of the JimStim. The two-dot processor had the wrong pattern. He's sending me an updated chip.