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Help with building your Speeduino, installing it, getting it to run etc.
By Mancino
Don't worry, whatever info you need I'm glad to share. I know TS a bit, but I'm very new to Speedy so I need all the knowledge and expertise I can get. I've attached a few different logs. First is the log from the screenshot above. The next is from just now when I tried putting all my grounds back to the cylinder head, rather than separating them. That screenshot is shown on here...
PSIG wrote:
Tue Apr 13, 2021 3:10 pm
It's awesome that you're logging everything, as many of your clues are hiding in the logs. 8-) However, you graph differently than I do, and I can't see the relative interactions in a screen shot. Not intending to be a pain in your ass, but could you post the log file, rather than (or in addition to) a screen shot?
Sync Loss 4.13.2021.png
Sync Loss 4.13.2021.png (26.84 KiB) Viewed 491 times
(181.74 KiB) Downloaded 11 times
(168 KiB) Downloaded 10 times
By Mancino
LAV1000 wrote:
Tue Apr 13, 2021 5:04 am
Might be a bad injector or bad connection to injector.
Injectors are just small coils.
Or maybe a bad injector driver.
Does the injector wiring run close to crank sensor wiring ?
Possibly....I still get a random sync loss when they are disconnected too though. Definitely not as many, but still get some. The injector wiring meets at a section of the harness before it eventually goes to the ECU. I used STP wire for the cam/crank sensor. Those shields are grounded @ the ECU.

Something I just thought of is spark plugs...I'm using NGK BKUR7ET plugs. Looking at charts, it appears they are resistor type plugs. Am I reading this wrong? Maybe that's the problem?? :?
NGK_Plug_Chart_1.jpg (153.55 KiB) Viewed 488 times
By theonewithin
Sounds more and more like just a really bad wiring harness.

Might be best to look at building a new one or going through existing from end to end to ensure everything is good
By Mancino
theonewithin wrote:
Tue Apr 13, 2021 9:03 pm
Sounds more and more like just a really bad wiring harness.

Might be best to look at building a new one or going through existing from end to end to ensure everything is good
Not saying you're wrong, but I thought I did it all legit...

Can anyone answer me this question? For the analog sensors, the wiki page shows the grounds for them going right to battery...on my harness I ran both signal and gnd to the ECU and used the ground connections on the Speedy board IDC pins. The cam and crank sensor grounds are also tied at the ecu. From there the main ECU ground is tied to the cylinder head. The ignition grounds go to the cylinder head as well. Anything wrong with this??
By theonewithin
ECU grounds should go back to battery.

Sensor grounds you pick a pin as the sensor ground in the Speeduino.

All other grounds to battery.

Ignition grounds to head should be fine.

If ever in doubt, have a look at an OEM wiring diagram and copy it. ;)
User avatar
I created this diagram for visualizing the theme @theonewithin described. I hope it helps.


Note the WBO2 labels of H and S are Heater ground and Signal ground. Sensor grounds terminate at one point at the ECM. Power (high-current) grounds avoid this point. All control (ECM) grounds terminate as a "star" ground at a single point on the engine (typically the block). This is to avoid voltage offsets or ground loops between signal components and the processor, and to avoid using ECM ground wires to carry current to "balance" the grounds. In all cases, we try to avoid using ground wires that carry current for grounding signal components. Current affects signal accuracy.
ECM_Grounding.png (52.14 KiB) Viewed 446 times
By Mancino
I'm going to write out a wiring diagram today...maybe there is something I combined with something I shouldn't have.

Could my shield termination be the issue? Where would you guys terminate the shields? I landed them to a small ground block inside the ECU box. Of which the ECU ground hits that point. This is how we wire our controls at work.
User avatar
Typically, a signal wire with shield would route the signal to its pin and the shield to an ECM power-ground at the ECM. This is to help separation of the signal from the noisy shield, and route that noise on the shortest path from the shield through the power-ground wire to the block. This is all a bit of juggling, as all of the grounds are in-fact connected, and the effort is to create clearer paths for signals versus noise and current.

There are no clear and hard rules, but after looking at the various flows, you can begin to see how you can avoid crossing or blending the various activity, if you see what I mean. This does not guarantee that you eliminate issues, but goes a long way towards avoiding them.

I would also suggest you try "sniffing" for noise when the circuits are active. If the issue is EMI, you should be able to detect and locate it by sniffing with an AM radio or an oscilloscope probe with a short length of wire attached as an antenna. EMI issues are generally large detections and sources (fans, starters, coils, plugs and plug wires, etc). You will always find EMI, and it's up to you to determine if the source is the type or frequency to be causing your problem.

If no joy finding large EMI, then you could begin testing wiring and connections. In most cases the issue becomes fairly obvious with one test or another, and you then have some direction to go in finding the issue source and fixing it. Good luck!
By Mancino
I found a few things that are odd....can anyone just confirm something for me?

First, when I apply 12v power directly to the Speedy board while having the injector connectors installed(but no switched power to them), the LED's for injector channel 1&2 stay lit( I don't hear the injector open though). When I unplug the injectors or supply 12v to them as well, the LED's go away....Am I reading the schematic wrong? Because I don't think that should happen... :?

Second, when I first apply 12v power to everything (injectors, coils, ECU) and the USB is not connected, the injector channels (1&2) fire what I assume is the 2ms priming pulse I have set. But It will also do this when I connect the USB while 12v is supplied. And if the car is running, it will kill the engine...is that normal? Or just another problem with my noise issue?

Hopefully I explained that well enough for you guys to understand...
Yes & Yes

Very vague here, but as the injectors switch on/off on the ground side, the leds can still light with no 12v to injectors.

Yes, priming pulse.

Applying usb to an already running engine, resets the arduino and causes it to restart. You can avoid this if you wish by cutting the usb 5v supply in the cable.
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