Speeduino is now on Github Sponsors (Rather than Patreon): https://github.com/sponsors/noisymime
Any general discussion around the firmware, what is does, how it does it etc.
Hi Rowdy,

I haven't hooked it up to the jeep yet. I bought some multi color wire to make a harness but for the first go I will just be hooking up the Crank sensor and the distributor sensor and power and ground to see if RPM/sync registers.

your 94 should have the same signals as my 97. they list the distributor compatibility as 1991-1997. They 1994 flywheel should have the same notches in it as well.

I wouldn't mind adding logic level coils if I can get the crank and distributor signals to work with the speeduino.

I'll let you know once I test it.

Thanks for the reply. I was reading and realized I will need to use the custom decoder you made since we don't have an equal interval tooth pattern. Your decoder makes sense to me. Do I need to put the new decoder into the speedy loader code and compile or is there a way to load it as a configuration?
Also, I have been typing up my wiring/pin layout I will post here soon with several other questions . For example, regarding ignition wiring using existing single coil and distributor:
a) Should I use the Distributor ignition wiring model and go to the single coil from Pin 7? If so what TunerStudio settings would I use? (Note: stock Jeep coil does not have igniter, an igniter has to be to connect to Speeduino, then in TS use Single Channel Spark Output Mode)
b) Should I use the Sequential COP ignition wiring model and splice all four wires into one for coil signal wire? Will feedback into the non-firing pins on the board be a problem?

Thanks again,
Last edited by RowdyDouglas on Wed Jan 26, 2022 1:02 am, edited 1 time in total.
Hi Rowdy,

I just downloaded the latest firmware from github and loaded the speeduino.ino into the arduino ide and made those changes in the "decoders" tab in the "Jeep2000" section (not decoders.h) that should work with the 2.5 and then saved it. Then I made those changes about compiling for speed and then saved and uploaded to the mega. https://wiki.speeduino.com/en/Installing_Firmware in the "Compiling the Firmware" section.

As for the tunerstudio stuff, I havent really dived into that yet. I mean i installed tunerstudio on my raspberry pi 4 and connected it to the speeduino and hooked up some temp sensors and made sure it worked on my kitchen table but I havent ran through all the ignition settings that i will be using. I plan to start with basic single coil and use the distributor because that is what is in the vehicle. I have some BIP373 coil drivers kicking around the house somewhere and I'll probably use that for now.

you may want to search for tunerstudio and coil on plug to see what the general setup is for that. I dont think you trigger all the coils from one wire though if i understand what you wrote. there should be logic level outputs for each individual coil trigger.

Correction edit: Our coil is not "smart". It only has 2 wires: one is 12v constant and one is 5v signal wire. In other words stock 1994 Jeep coil does not have igniter.
An igniter has to be used to connect to Speeduino, then in TS use Single Channel Spark Output Mode)
Last edited by RowdyDouglas on Wed Jan 26, 2022 1:48 am, edited 3 times in total.
theonewithin wrote:
Thu Aug 05, 2021 3:50 am
Set it up as distributor in Tunerstudio.
I wish @theonewithin would say how he really feels. :lol: With single-channel output (same output as Distributor mode uses), the wiring would be like this:

Single Channel output wiring mod.jpg
Single Channel output wiring mod.jpg (65.18 KiB) Viewed 3300 times
edited for terminology
Last edited by PSIG on Fri Aug 06, 2021 2:02 am, edited 2 times in total.
Thanks for the replies @theonewithin and @PSIG. I am planning to use the modified Jeep_2000 decoder @reliant_turbo made which uses cam and crank sensors. By Distributor mode in Tuner Studio do you mean Single Channel Spark Output Mode, the wiring diagram @PSIG made and custom decoder?
@PSIG, great, thanks. Onto a different but related question: my cam sensor, crank sensor and vehicle speed (VSS) sensor are supposed to share an 8v constant. Do I have to install a transformer to get 8v out of the Speeduino? If so where on the board do you recommend and output pin?
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