JimStim

[dragbiker1]

I am a newbie using MS. I have purchased a Microsquirt with a relay board and a JimStim v1.3. Is there any documentation on how to hook up the JimStim. I am planning on using this for a dragrace motorcycle that is turbocharged and would appreciate any input from others. The Engine is a 1428cc Suzuki engine with 38mm throttle bodies off of a late model GSXR. I have been using another system, but I plan to convert to alcohol this season. I have low impedance injectors to supply 175lbs for this. With gasoline I am running 82 lbs.

[newtyres1]

Here is a link for info on the Jimstim http://www.jbperf.com/

If you are going to run low-Z inj's with Microsquirt you will proly need the peak and hold board at the same link.

The Jimstim is a nice versatile piece of gear.

To actually connect the Jimstim to the Microsquirt you will probably need to make an adapter cable with a Microsquirt connector on one end and a DB37 male on the other end. I don't think many people have connected a Microsquirt to a stim but it's a really good way to set it up and check it out.

The Jimstim, like the standard stim, was designed to plug straight into a Megasquirt which already has a DB37 female connector, so an adapter cable is not necessary. With Microsquirt, you will have to draw up a wiring diagram for the adapter cable and build it. I don't think you can just buy one, but if there is a demand I'm sure DIYAutotune or someone would come up with one for sale. Might be an idea to contact DIYAuto for connector prices or the possibility of building an adapter cable for you.

Ian.

[racingmini_mtl]

Actually there is no need to have a DB37 connector: that's what the screw terminals are for. You can just use the wires from your wiring loom (of course that would be before you put it in the car). You could make an adapter cable but that's not necessary. And the screw terminals are identified to show which signal goes to which position so if you use the Microsquirt connector schematic, you'll be able to see which wire goes where.

Jean

[24c]

... And the screw terminals are identified to show which signal goes to which position so if you use the Microsquirt connector schematic, you'll be able to see which wire goes where.

Jean, do I only use the screw connector blocks? I am struggling with this and not finding it straight forward. Any help would be appreciated, as I don't want to damage this µS or JimStim board. I have no MSII knowledge so the labelling I1A...I2B is confusing,

I must be thick

[Matt Cramer]

The Microsquirt doesn't have stepper IAC wires. You can use these screw terminals for other outputs but usually you won't need to hook them up.

[jsmcortina]

Attached is a photo of a Microsquirt hooked up to the JimStim. That's what the screw terminals are provided for.

If you still need assistance on what goes where I'm sure the main JimStim site can be updated with Microsquirt specific connection instructions.

James

jimstim_microsquirt.jpg

[racingmini_mtl]

I have added a page to the web site to show how to connect the Jimstim to the MicroSquirt : http://jbperf.com/JimStim/JimStim_Micro ... ction.html.

Jean

[MK_Micro]

Cool stuff. Just received my MicroSquirt and tried to hook it to my JimStim.
At least it connected to the PC, but there was no rpm or other sensor signal coming through.
After checking the MicroSquirt wiring help I saw that I forgot to connect sensor ground ....

I wasn't sure about OptoIn- - the link showed what I would have tried next (ground).

I'm still not 100% sure about the Vref cable coming out of the MicroSquirt. What I understand was that this is a 5V supply coming FROM the MS-PCB to feed the TPS and MAP sensor.
Now the JimStim also has a 5V supply and in the linked document you suggest to connect these two 5V sources. Wouldn't that damage either one or both of them ?

[racingmini_mtl]

The JimStim has a 3.3V supply to power it's own CPU. The 5V supply (Vref) from the Microsquirt is used to power all the LEDs and TPS signal on the JimStim. There is no conflict with the power supply on both boards because they are not connected together since the JimStim is designed to get its 5V from the Microsquirt (or the MegaSquirt).

Just connect the Microsquirt wires as per the instructions and everything will be fine. If you still don't get the sensor signals or any RPM, post here and I'll do my best to help you out. By the way, there is no dedicated MAP pot on the JimStim but you can use the SPARE pot as mentioned in the instruction. Just connect a wire jumper from the spare pot pin header to the SPR2 pin on the 19-pin header (if you connected the Microsquirt MAP wire to the SPR2 screw terminal as per the instructions).

Jean