DaveEFI wrote: ↑Wed Jan 06, 2021 10:00 am
Excellent progress. Is there not a spare output on Nodiz which can be configured to give the same signal as the diodes from coils? That idea is only usually needed to give a high voltage pulse to older tachometers. Dunno about later systems, but on the Flapper injection the engine tach signal is obtained via a resistor from the coil negative. Remove that resistor and it triggers from a low volt signal. I made an adaptor lead to check a 4CU ECU using a MegaSquirt JimStim. It triggers happily from that.
Cheers Dave. Only problem with that is I don’t know what is meant by “older”. Talking to some snowflakes would lead you to think that was pre-2018, to me “older” means pre 1960!
What I do know is that it has up to now both Tachometer & 14CUX picked up a signal from the -ve terminal of the single coil.
What form of signal it gets from here I do not know. I’d love to put an oscilloscope onto this to find out but don’t have access to one.
From what I’ve heard discussed I’m assuming this is a “high” voltage “spike” however I don’t know what is meant by high.
What I originally tried was linking the Nodiz Tacho output (apparently a 12v square wave) to the 14CUX (Tacho not mission critical at this point) and the 14CUX was obviously not happy with this, fuel pump didn’t restart and no RPM signal shown in Rover Gauge.
I then tried linking to the opposite side of the resistor (assuming I’m now working with a lower voltage signal, 12v), this did not work either so I moved on to the diodes.
I since realised that there are 2 feeds taken from the single cable linked to the coil (don’t know where the second one goes, need to re-check my data) and when I removed the (6k7) resistor I may have linked to the “wrong” input.
I will be re-visiting this before I make up my “production” loom as I’d rather use this, simpler, signal.
Once I had the engine running I then turned my attention to the car’s Tacho. I tried linking this to the Nodiz Tacho output and it did work BUT was reading half true speed.
There is a setting in EZ-Tune for pulse/rev’, obviously for a v8 this needs to be 4. Unfortunately I could not commit this setting to the unit, I could also not check what the current setting is, the software doesn’t make this obvious. I’m assuming it was set to 2, the standard setting for 4 cylinder.
I’ve communicated this back to Supplier. Hopefully this can be sorted but not worth trying to use this signal until I’ve got the correct frequency.
DaveEFI wrote: ↑Wed Jan 06, 2021 10:00 am
You'd normally check the actual spark timing using a timing light and scale on the pulley, etc. Adjust the offset so the true timing agrees with the software one. With wasted spark a simple basic timing light can be best - some 'smart' ones don't like wasted spark.
That’s exactly what I have done, but could only do that once I got the engine to run.
The suggestion from Nodiz is to put the unit in a mode which sets timing to constant zero degree then crank the engine (with start inhibited), watch the timing mark and tweak the base offset to get the zero point on the pulley to align with the pointer.
I had a couple of issues here. Firstly, although simple, my timing light does not flash when cranking, only when running so no way of working as per instructions.
Second issue was that the value for this base offset did not work as I expected so the setting I started with did not allow the engine to start.
Thirdly, although I can see the BO setting in EZ-Tune I could not set it, comm’s issue again, so had to set using the buttons on the unit. What I did was keep shifting the value 10* until the engine ran (just) at which point I could correct it using the (now working) timing light.
Now my zero degrees is correct any angle output by Nodiz will also be correct.
Hope that makes sense!