- Thu Feb 20, 2020 1:12 am
#41029
I've been chasing a hard starting issue on my car these past few days, and got it narrowed down to one issue. The car sync-losses during cranking, so it's extremely hard to start. Once it's running it doesn't ever lose sync at all.
Car is a 97 Miata with a fishdog board and pnp harness from speedyefi installed early 2019. Looking at my logs from back when I first installed it, the car never lost sync during cranking. There were plenty of other issues, but sync loss wasn't one of them. The only big electrical modifications I've made since then have been converting to coil-on-plug ignition, converting to an NB miata throttle body and idle valve, and an NB Miata starter. I have logs before and after these mods, and there was still no sync loss casued by their install.
This problem has been creeping up it seems. The past two days have been all troubleshooting. Installed a good crank position sensor, but that didn't change anything. Still lost sync on crank but never while running. Found out that if I unhook the coil packs from the spark plugs and crank the car, it never loses sync. I reinstalled stock ignition and it was the same thing. Perfect sync until the plug wires touch the spark plugs. Thought maybe the NGK BKR7E plugs were causing the issue somehow, so I bought cheap parts store copper plugs, and still had sync loss. I've had sets of Iridium BKR7E in the car since the ECU install so I don't get it.
Also I've only ever used the March 2019 firmware, because I wanted the tune really rock solid before adding features. The car went to the dyno recently, and once it fires, it runs great. Is there different electrical noise filtering on the new firmwares I'm missing? I've tried all the trigger filters, from off to aggressive and all of them still lose sync during cranking. What am I missing here? Could a driver on the board have been degraded? Some kind of grounding issue? Or the battery voltage dropping too low? I only dip to around 10v cranking. I've read a thread about a megasquirt that had this problem due to dwell correction being low at cranking, causing misfires that made bad EMF that caused sync loss. My settings seem good though. I know the car will start great once I figure this out, because when it only loses sync one time it fires right up.
I've attached my tune and 2 cranking logs . I'm currently rewriting it to the newest firmware.
Car is a 97 Miata with a fishdog board and pnp harness from speedyefi installed early 2019. Looking at my logs from back when I first installed it, the car never lost sync during cranking. There were plenty of other issues, but sync loss wasn't one of them. The only big electrical modifications I've made since then have been converting to coil-on-plug ignition, converting to an NB miata throttle body and idle valve, and an NB Miata starter. I have logs before and after these mods, and there was still no sync loss casued by their install.
This problem has been creeping up it seems. The past two days have been all troubleshooting. Installed a good crank position sensor, but that didn't change anything. Still lost sync on crank but never while running. Found out that if I unhook the coil packs from the spark plugs and crank the car, it never loses sync. I reinstalled stock ignition and it was the same thing. Perfect sync until the plug wires touch the spark plugs. Thought maybe the NGK BKR7E plugs were causing the issue somehow, so I bought cheap parts store copper plugs, and still had sync loss. I've had sets of Iridium BKR7E in the car since the ECU install so I don't get it.
Also I've only ever used the March 2019 firmware, because I wanted the tune really rock solid before adding features. The car went to the dyno recently, and once it fires, it runs great. Is there different electrical noise filtering on the new firmwares I'm missing? I've tried all the trigger filters, from off to aggressive and all of them still lose sync during cranking. What am I missing here? Could a driver on the board have been degraded? Some kind of grounding issue? Or the battery voltage dropping too low? I only dip to around 10v cranking. I've read a thread about a megasquirt that had this problem due to dwell correction being low at cranking, causing misfires that made bad EMF that caused sync loss. My settings seem good though. I know the car will start great once I figure this out, because when it only loses sync one time it fires right up.
I've attached my tune and 2 cranking logs . I'm currently rewriting it to the newest firmware.
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