Help with building your Speeduino, installing it, getting it to run etc.
#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.
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#41090
Alright, so a friend and I tested all the grounds today with his multimeter. They all had good continuity and little to no resistance. Still lost sync after cleaning them. Tried the new Feb 2020 firmware and the tuner studio update, still lost sync a bunch and the car ran worse when it actually did crank over (but that's besides the point). I'm at a loss on what's left to rule out.

On the pinout I made of my ECU, I see that both the crank position sensor & cam sensor signals are used. I changed the crank sensor and nothing improved. Should I look into replacing the CAS too? I just find it weird that once cranking is over and the car is running, it doesn't lose sync even all the way to redline. I just can't think of many more possibilities that would change things. Does tuner studio work with the Speeduino to give error codes for the sync losses? I know megasquirt does so that you can see why it lost sync.
#41114
I was having problems with the engine running along happy then suddenly sync loss and die. I checked all the grounds and voltages and connectors for loose connections. Nothing seemed to help. I bought a box of ferrite noise filters and put them everywhere. Both power lines, All input and output cables and at both ends of the cable running to the crank position sensor. Don't know which one fixed it but now it runs fine.

https://www.amazon.com/gp/product/B07ZQ ... UTF8&psc=1
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#41115
Theonewithin, you were pretty much right on the money. I was thinking my cam angle sensor was going bad so I was so invested in that, I didn't think of the starter. Last night I checked my logs before and after installing the starter months ago, and what you said was looking to be true. Friends and I changed starters this morning, and I went from about 40 sync losses before starting to 1 or 2. Still need to get that number to 0, but it's way more stable now.

Hello, I figured out it was a sync loss problem because it was getting hard to start lately and I didn't know why. Opened my laptop and watched the green bars at the bottom of tuner studio and saw that while I was cranking the car the sync bar was flashing on and off. Then I checked my logs and confirmed the issue.

Gpineau, I'm glad I'm not alone lol. All my grounds tested good and I still cleaned them and it didn't fix anything until changing the starter. Still get some losses though so I might get some of those noise filters. I plan on getting my ecu on my friend's car of the same year to see if it's more than just my car. I'm guessing I just have electrical gremlins somewhere that other miatas wouldn't.
#41130
[quote=Guidosaur post_id=41127 time=1582577616 user_id=2529]
Alright so the sync losses are back :lol: still much better cold starts with the different starter because it loses sync less, but still bad. Gonna use a friend's stock Miata tomorrow with a base tune and confirm it's not my ECU. If his car works I'll just be buying a bunch of ferrite rings lol. I'll add a video of the behavior when I can get to my PC. Phone is bit crunching the hell out of the video to where it's unwatchable.

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