Help with building your Speeduino, installing it, getting it to run etc.
By Zipdrive
Hello all,

We have just embarked on another project for my son's 95 XJ. The original problem was that the ECU was bad and causing random stalls and hard starts afterwards. After replacing the 3 caps with new ones on the original ECU and getting the same behavior, my son had paid for diagnostics to tell us what else it could be. They confirmed the ECU, and after buying a second factory ECU, had the same problems. We even bypassed the Auto Shut Down relay and still had the same issues.

Our goal is to create a new ECU, V0.4.3d, and a new wiring harness which lays along side of the old one, vs tearing out the old one and trying to merge the two together. I've spent more than a few hours reading the wiki, looking through the forum, but very little time on discord. Its not intuitive for me and I find it difficult to comb through it.

* Does anyone know what brand / series of connectors were used on the 90s Mopars, explicitly Jeeps?
* I think I've found new fuel injector connectors, Standard Motor Products, HP3980. Can anyone confirm?
* for all of the sensors that use 2 or 3 wires, would the Aptiv (Delphi) Metri pack 150 series work?
* Dropbear uses a set of Delphi Sicma 24 pin connectors. Does anyone know where to buy these with flying leads attached already? If not, where is the best place to by the shells, pins / sockets, and tools to build up the connectors? Has anyone put together a parts list of items needed to build these connectors from parts?

* To wire up the injectors correctly, do I tie Pin 1 and 40 together (say inside the ECU housing), and then wire them to Inj 1 and Inj 6 in series, OR, do I wire pin 1 to Inj 1, and pin 40 to Inj 6?
* Grounding - is the best grounding scheme to tie all of the ground points on the ECU to one isolated ground inside the chassis, and then take a single large ground wire back to the neg of the battery?
* wiring is all 20 gage currently. Is this sized adequately?

I'm sure I'll have a lot of questions as I continue developing the wiring diagram. Thank you for your help and time.
By dazq
The injector outputs on the idc 40 are paired and should be joined , eg pin 1 and 40 are both injector 1 channel . If you examine the PCB you will see they are joined together.
Injectors should NOT be wired in series!
Is you original loom damaged? Many people use the original loom without modification by fitting a socket from a old spare ECU onto the speeduino.
By brainz
doing the same here shortly (v4.3 turbo 4.0) ill try 3-1 , 3-3. and eventually 6-6 full.
i harvested original connector from old scrap ecu and for now will use idc40 breakout as connection.

ive found ms3 maps which i havnt tested but ??
update progress
By Zipdrive
Dazq: Well... I was thinking of making a new harness as it seemed "easier" and less potential for problems since it would all be new. Some of our connectors are missing parts of their shells and are held together by floss and zip ties. Don't you have to re-wire the injectors to run with the speeduino correctly? I did not think that the V0.4.3d would allow sequential injection.

I'll take the suggestion to simplify integration, and pull the connector from the old board and try it first and see if it runs If I don't have to re-wire anything in the original harness.

Brainz, are you referring to the injection sequence, with 3-1, 3-3, and 6-6? I'm not sure what these mean. I'll be using the 3 injector drivers to run each pair of injectors. i.e. inj driver 1 runs inj 1 and 6, inj driver 2 runs inj 2 and 5, and inj driver 3 runs inj 3 and 4.
By dazq
If each injector is separately connected to the OEM ECU via its own wire then it will be easy to pair up after the OEM socket to connect to the speedy board.

Injectors are generally wired as one side to ignition switched live the other to the ECU outputs.
If this is how yours are then they will work fine with speedy.
User avatar
A 4-channel ECM cannot fire fully sequential without modification to create two additional INJ channels. However, as you have wired your injectors paired the same as waste-spark, it can inject 3 pairs in quasi-sequential, also known as double-shot sequential. This requires a cycle (cam) signal.

As sequential is considered as injecting on a cylinder with consistent repetitive timing each cycle, e.g., Cyl5 is always injected at 120° every cycle (720°); quasi does the same but half the fuel twice on each cycle (once every crankshaft revolution) at 120° and 480° . Some factory ECMs today use double-shot sequential for improved efficiency, so the concept is not lame. :lol:
By Zipdrive
Build Update - hence, more questions...

Is the orientation of the stepper driver correct for the install into the main board, per the picture? I have not found any documentation that has a corresponding pin 1 on the main board or the driver board.

Speaking of documentation. I have only found the one video of by DCWrex. And it is of the 4.c and not the 4.d (version that I have). Is there any other instructions on building the board? I found a pdf titled v0.4.4d, useful, but not helpful (where is pin 1, how does that correspond to the layout on the board?).

There is a small spot on the board, JP11. What goes here? What is is used for?

Out of curiosity, why was IDC cabling suggested to be the interface cable from the main board to the car's harness? IDC is typically like 32 AWG and has low current carrying ability vs, the cars wiring harness. I found a 26 AWG as a quick solution for testing and checkout, but still not a good final solution (as in I think it should be closer to the wire gage that the harness uses, but that's my opinion). What are others typically doing for the interface between the main board and the harness?
What component goes here?
What component goes here?
JP11 - ECU.jpg (111.02 KiB) Viewed 2931 times
Orientation of the step dvr CCA, correct?
Orientation of the step dvr CCA, correct?
Stepper Idle Driver orientation - ECU.jpg (111.2 KiB) Viewed 2931 times
User avatar
Go to the Speeduino Hardware page to find info on your board. Not all boards have PDF schematics or PCB images. Without info, you can see a resistor is connected to JP11, and that resistor should tell you what circuit the JP is involved-with. I can't see the resistor number, so that's for you to find.

For the DRV8825 driver placement, the instructions are on the PCB. Read and follow those words, as in your image below.
044d_DRV_words.jpg (113.58 KiB) Viewed 2733 times
You can use junk wiring and connectors or good stuff with the IDC. ;) Some use standard 22AWG jumpers in the IDC connector. I have found 24AWG ribbon cable that I use, that has high-amp terminals. Some also do not use the IDC connector at all, and simply solder 20 or 22 AWG directly into the connector pin holes, which is very robust. While the wires are light, they are short, and higher-amp circuits are double-pinned for current capacity. @noisymime did an IDC current test video that goes a long way to calm concerns. I hope that helps.
By Zipdrive
Oh, that's a little embarrassing... should have 'read / seen' a little more on the module position. :(

I'll have to dig into the JP11 on the hardware page. Thank you for the direction to look.

Good to know that others have had good success with short thin gauge wiring.
Ground question: Tie all grounds to one isolated point (inside the housing) and tie that single point back to the neg of the battery vs. "chassis" ground on the engine block?
By Zipdrive
Ground - further look...

I have 4 ground pins on the engine harness. I don't think I should tie them one to one, engine harness to ecu grounds, but all together at a common isolated point, and not to the battery, yes?

Thank you.

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